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Aims: To investigate the clinical characteristics of Leber hereditary optic neuropathy (LHON) with mtDNA primary mutations to better understand features associated with prognosis., Methods: This study enrolled 1540 LHON patients from 1516 unrelated families genetically confirmed by Sanger or whole-mitochondrial sequencing between 1997 and 2022. The spectrum of variants was summarised and compared in different ethnic groups. Clinical data from outpatients were collected, including onset age, disease course, optic disc categories and the corresponding visual acuity., Results: Of the 1516 LHON families, 13 pathogenic mtDNA variants were detected, in which the proportion of m.11778G>A, m.3460G>A and m.3635G>A was significantly different from non-East Asians (p<0.0001). About 95% (1075/1131) of patients were between 8 and 40 years old at onset, with a median onset age of 16. The eyes of m.14484T>C patients presented with better visual acuity and slower progression across patients with different onset ages and initial severity. Eyes (N=439) with available fundus images were divided into four categories (C1-C4). The progression grades were derived from the category and the corresponding time course, where a higher grade (C3-C4 within 1 year) was associated with greater visual impairment than a lower grade (C1-C2 over 1 year) (p=4.60E-05) . A prognostic matrix showed that later onset and a higher progression grade are associated with higher risk of blindness., Conclusion: Compared with non-East Asians, Chinese LHON patients had higher proportions of m.11778G>A and m.3635G>A and lower m.3460G>A mutations. A novel progression grade derived from optic disc category was proposed. The prognostic matrix indicated that lower grade and younger-onset age are the most favourable prognostic factors., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Leber congenital amaurosis (LCA) is the most severe form of retinopathy and cone/cone-rod dystrophy (CORD) is a common form of inherited retinopathy. Variants in GUCY2D constitute the most common cause of LCA and autosomal dominant CORD (ADCORD). The purpose of this study was to reveal novel variants and document associated phenotypes of patients with GUCY2D-associated retinopathy. Fifty-two potentially pathogenic variants (PPVs), including 12 novel ones (p.Gly144&#95;Ala164del, p.Trp154Glyfs*12, p.Leu186Pro, p.Ala207Pro, p.Ala229Asp, p.Ala353Glu, p.Trp372*, p.Arg528*, p.Arg660Pro, p.Ile682Thr, p.Trp788Cys, and c.1026 + 171&#95;*486del), were identified in 16 families with ADCORD and 34 families with autosomal recessive LCA (ARLCA). The novel variant c.1026 + 171&#95;*486del is a large-scale (16.3 kb) deletion involving exons 4-20 of GUCY2D, and was identified in an ARLCA family in heterozygous status mimicking a homozygous p.Trp788Cys variant. Among the detected 52 PPVs, 32 (61.5%) were missense, seven (13.5%) were splicing, six (11.5%) were nonsense, four (7.7%) were inframe indel, and three (5.8%) were frameshift deletion. The median age of examination in 27 patients with ADCORD was 21.0 years (ranges 3-54) with a median visual acuity (VA) of 0.10 (ranges 0.02-0.90). There were 48.0% of patients with macular atrophy, 86.4% with severe reduced or extinguished cone responses, 77.3% with normal or mildly reduced rod responses, and 60.9% with high myopia. Visual impairment, macular dystrophy, and cone dysfunction deteriorated with age. The median age of examination in 34 patients with ARLCA was 1.1 years (ranges 0.3-25). There were 55.9% of patients with roving nystagmus, 68.2% with VA of worse than hand motion, 59.4% with almost normal fundus, 90.6% with extinguished rod and cone responses, and 50.0% with high hyperopia. In conclusions, twelve novel PPVs in GUCY2D (including a novel large-scale deletion) were identified. Most (32/52, 61.5%) of causative GUCY2D variants were missense. Progressive development of macular atrophy, cone dysfunction, visual impairment, and myopia are four major characteristics of GUCY2D-associated ADCORD. Normal fundus, roving nystagmus, and hypermetropia in early age are common findings specific to GUCY2D-associated ARLCA. The obtained data in this study will be of value in counselling patients and designing future therapeutic approaches., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Purpose: To reveal the characteristics of ocular changes in patients with biallelic CRB1 mutations., Design: Comparative exome sequencing and retrospective case series on clinical data., Methods: Seventy-four patients from 63 families with biallelic potential pathogenic variants in CRB1 were selected from our in-house exome sequencing. The clinical data were reviewed and evaluated in detail, including best-corrected visual acuity, fundus photography, optical coherence tomography (OCT), and electroretinogram (ERG)., Results: Biallelic CRB1 variants, involving 45 variants including 23 novel, were identified in 40 novel families based on exome sequencing. Analyzing clinical data of the 74 individuals from 63 families revealed the following CRB1-associated phenotypes: (1) early-onset reduced visual acuity with congenital nystagmus; (2) 2 types of characteristic retinal changes including yellowish geographic macular degeneration (YMD) or nummular pigment deposits (NPD) at posterior retina with bone-spicule pigmentation at midperipheral retina; (3) undetectable rod and cone responses on ERG; (4) cystoid macular edema or macular atrophy on OCT. YMD and NPD are unique and CRB1-associated. Long-term follow-up examination as well as age- and variant-dependent phenotypic analysis suggested YMD is the early fundus change that would gradually progress to NPD., Conclusions: YMD and NPD are 2 major characteristic CRB1-associated fundus changes and the former one will advance to the latter with age. Recognizing such characteristic signs associated with biallelic CRB1 variants may be of value in areas without widespread access to genetic testing where a more targeted approach is needed and might be biomarkers for evaluation of effects for future intervention., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

Purpose: To describe the mutation spectrum of SPATA7 and associated ocular phenotypes., Methods: As part of a continuing examination of the genetic basis of inherited ophthalmic diseases, sequencing variations in SPATA7 were identified in sequencing data from 5,090 probands. Mutations in SPATA7 were identified in 12 Chinese patients from ten families. Family history and clinical data were examined in detail in these patients. To evaluate possible gene-specific fundus changes, the results were combined with data from 66 patients from 50 families previously reported in the literature., Results: Seven homozygous or compound heterozygous mutations, including two novel mutations (c.367C>T, p.Q123* and c.1083-2A>G) and five known mutations in SPATA7 , were identified in ten families, including six families with Leber congenital amaurosis (LCA), three families with juvenile retinitis pigmentosa, and one family with early-onset high myopia. These families accounted for approximately 2.2% (6/269) of LCA and 0.4% (10/2,252) of inherited retinal dystrophies in this case series. A combined analysis of data from the present study and data from 60 families reported in the literature showed that 93.3% (112/120) of mutant alleles were truncation mutations, whereas only about 5.0% were missense mutations, and 1.7% were non-frameshift indels. Common SPATA7 -associated fundus changes, including narrow arterioles, a relatively well-preserved macular region, and widespread RPE atrophy resulting in diffuse mottled hypopigmentation in the midperipheral retina, were identified in this cohort and in patients in the literature. Missense mutations were not associated with specific phenotypic features or severity., Conclusions: Narrow arterioles, a relatively well-preserved macular region, and widespread RPE atrophy resulting in diffuse mottling hypopigmentation in the midperipheral retina may be considered early and common fundus changes specific to SPATA7 -associated retinopathy. The fact that similar mutations result in varied phenotypes points to the existence of other potential modifiers of the disease. Uncovering the identity of these modifiers might aid the development of novel treatments., (Copyright © 2019 Molecular Vision.)

High hyperopia is a common and severe form of refractive error. Genetic factors play important roles in the development of high hyperopia but the exact gene responsible for this condition is mostly unknown. We identified a large Chinese family with autosomal dominant high hyperopia. A genome-wide linkage scan mapped the high hyperopia to chromosome 11p12-q13.3, with maximum log of the odds scores of 4.68 at theta = 0 for D11S987. Parallel whole-exome sequencing detected a novel c.3377delG (p.Gly1126Valfs*31) heterozygous mutation in the MYRF gene within the linkage interval. Whole-exome sequencing in other 121 probands with high hyperopia identified additional novel mutations in MYRF within two other families: a de novo c.3274&#95;3275delAG (p.Leu1093Profs*22) heterozygous mutation and a c.3194+2T>C heterozygous mutation. All three mutations are located in the C-terminal region of MYRF and are predicted to result in truncation of that portion. Two patients from two of the three families developed angle-closure glaucoma. These three mutations were present in neither the ExAC database nor our in-house whole-exome sequencing data from 3280 individuals. No other truncation mutations in MYRF were detected in the 3280 individuals. Knockdown of myrf resulted in small eye size in zebrafish. These evidence all support that truncation mutations in the C-terminal region of MYRF are responsible for autosomal dominant high hyperopia in these families. Our results may provide useful clues for further understanding the functional role of the C-terminal region of this critical myelin regulatory factor, as well as the molecular pathogenesis of high hyperopia and its associated angle-closure glaucoma.

Background: Leber congenital amaurosis (LCA) is the earliest and most severe form of inherited retinal dystrophies. In approximately 56% of Chinese probands, genetic defects can be detected in known LCA-causing genes. In this study, the objective was to identify pathogenic variants in two unsolved Chinese families with LCA., Methods: To identify the genetic defect, whole-exome sequencing (WES) and clinical analysis was performed in both probands with LCA as well as in 3011 in-house controls with other hereditary eye diseases. The expression profiles, as well as the phenotype analysis of knockdown zebrafish model and knockout mice model, were performed to investigate the function of USP45 in photoreceptors., Results: By analysing WES data based on allele frequencies of in-house controls, population allele frequencies and in silico prediction tools, two rare homozygous mutations in USP45 were identified in two unrelated families. Immunohistochemistry of USP45 in the human and zebrafish retinal sections revealed enriched expression in the inner segments of photoreceptors. The knockdown of usp45 transcript in zebrafish led to abnormal retinal development with effects on photoreceptors, which could be successfully rescued by wild-type usp45 mRNA. Moreover, targeted knockout of Usp45 in mice caused abnormal electroretinography responses, similar to that seen in patients with LCA., Conclusions: Our study implicates that biallelic mutations in USP45 are associated with the occurrence of LCA. Moreover, our results indicate that USP45 is indispensable to the maintenance of photoreceptor function., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose/aim of the study: To conduct a survey spectrum of the PITX2, FOXC1, and PRDM5 genes to reveal genotype-phenotype correlations in a cohort of Southeastern Chinese patients with Axenfeld-Rieger syndrome (ARS)., Materials and Methods: A total of 20 probands with ARS were recruited in Southeast China. All patients underwent full ocular and systemic examinations. Sanger sequencing was used to analyze all coding regions of and regions adjacent to PITX2, FOXC1, and PRDM5 and 13 upstream regulatory elements of PITX2. Multiplex ligation-dependent probe amplification was performed to detect gross insertions and deletions in PITX2 and FOXC1. Quantitative polymerase chain reaction was used to detect copy number variations in regulatory elements of PITX2. A bioinformatics analysis was conducted to evaluate the pathogenicity of variants., Results: Eleven mutations, including eight novel mutations, were identified in PITX2. Seven of the mutations were truncations. A genotype-phenotype correlation analysis showed that 81.8% (9/11) of patients with mutations in PITX2 developed glaucoma before reaching 10 years old. The proportion of patients without detected mutations was only 33.3% (3/9, P = 0.0399). In patient G1399, ultrasound biomicroscopy revealed that the left eye exhibited a phenotype similar to aniridia with complete angle closure and a remaining stub of iris tissue., Conclusion: This is the first genetic study of a cohort of Southeastern Chinese patients with ARS. Eight novel mutations were detected, expanding the mutation spectrum of PITX2. PITX2 may be a major candidate gene for ARS in Southeastern Chinese patients. Truncations may be the primary mutation type in PITX2. Glaucoma onset may be earlier in patients with mutations in PITX2 than in those without mutations in PITX2 and FOXC1. A block of the anterior chamber angle by the end of the iris might represent the main factor influencing the development of glaucoma in ARS patients with an asymmetric aniridia phenotype.

Purpose: Our previous study reported that 5.5% of probands with early-onset high myopia (eoHM) had mutations in COL2A1 or COL11A1 . Why were the probands initially considered to have eoHM but not Stickler syndrome (STL)?, Methods: Probands and family members with eoHM and mutations in COL2A1 or COL11A1 were followed up and reexamined based on the criteria for STL. Further comprehensive examinations were conducted for patients with eoHM and mutations in COL2A1 or COL11A1 and controls with eoHM without mutations in COL2A1 or COL11A1 . We performed comparisons between probands, affected family members with mutations in COL2A1 or COL11A1, and controls with eoHM without mutations in COL2A1 or COL11A1 ., Results: Twelve probands (8.91±4.03 years) and 14 affected family members (37.00±11.18 years) with eoHM and mutations in COL2A1 or COL11A1 , as well as 30 controls with eoHM but without mutations in COL2A1 or COL11A1 , were recruited. Among them, 25.0% of probands and 50.0% of affected family members met the diagnostic criteria for STL after reexamination. Posterior vitreous detachment/foveal hypoplasia (PVD/FH), hypermobility of the elbow joint (HJ), and vitreous opacity were more frequent in patients with eoHM with mutations in COL2A1 or COL11A1 than in the controls (p = 1.40 × 10 -5 , 3.72 × 10 -4 , 2.30× 10 -3 , respectively). HJ was more common in the probands than in the affected family members (11/12 versus 3/14; p = 3.42 × 10 -4 ), suggesting age-dependent manifestation. EoHM presented in all the probands and in 11/14 affected family members, suggesting that it is a more common indicator of STL than the previously described vitreoretinal abnormalities, especially in children. The rate of STL diagnosis could increase from 25.0% to 66.7% for probands and from 50.0% to 92.9% for affected family members if eoHM, PVD/FH, and HJ are added to the diagnostic criteria., Conclusions: In summary, it is not easy to differentiate STL from eoHM with routine ocular examination in outpatient clinics. Awareness of atypical phenotypes and newly recognized signs may be of help in identifying atypical STL, especially in children at eye clinics.

In our previous study, potential pathological mutations of RetNet genes were detected in 23.8% (71/298) of probands with early-onset high myopia (eoHM), based on whole exome sequencing (WES). The current study aimed to confirm this finding in an additional 325 probands with eoHM and to clarify its specificity by comparison of 195 probands with late-onset high myopia (loHM). Variants in the 234 RetNet genes were selected from whole-exome sequencing data and were filtered using multistep bioinformatics analyses. Potential pathological variants in 33 genes were detected in 76 of 325 (23.4%) probands with eoHM and 14 of 195 (7.2%) probands with loHM. Thirty-five of the 76 (46.1%) probands with eoHM had mutations in COL2A1, COL11A1, RPGR, and CACNAIF, while only 2/14 (14.3%) probands with eoHM were detected. The mutation frequency and spectrum of RetNet genes in the 325 probands with eoHM were similar to our previous study but were significantly different in 195 probands with loHM (P = 2 × 10 -6 and 0.04). Data from eoHM and loHM strongly suggest that a significant proportion of eoHM is caused by mutations in RetNet genes. These results also provide initial genetic evidence that eoHM is different from loHM. The presence of mutations in 7.2% probands with loHM raises questions about pathogenicity and the variable manifestation of some mutations. The functional studies of the mutations in question and more extensive investigations of related phenotypes in the mutation carriers and their family members may provide valuable information to address these questions., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The purpose of the current study was to identify novel mutations in the FRMD7 (FERM domain containing 7) gene and to characterize clinical features in Chinese patients with congenital motor nystagmus. For this purpose, 18 patients with congenital motor nystagmus were selected from the ocular genetic diseases bank of the Pediatric and Genetic Clinic of Zhongshan Ophthalmic Center (Guangdong, China). Direct sequencing was used to analyze the exons and adjacent introns of the FRMD7 gene. The heteroduplex‑single strand conformation polypeptide method was used to analyze 96 unrelated normal controls and gene‑screening positive patients. Slit lamp photography of the anterior segment, fundus photography, optical coherence tomography and electroretinogram were carried out to identify the clinical features of congenital motor nystagmus. The authors noted that in, 18 patients with congenital motor nystagmus, there were 7FRMD7 gene mutations (six new mutations). The screening rate was 38.89%, including c.41&#95;43delAGA (p.13‑15delK); c.473T>A (p.I158N); c.605T>A (p.I202N); c.580G>T (p.A194S); c.811T>A (p.C271S); c.1493insA (p.Y498X); c.57+1G>A (slice mutation). There were no such mutations in the 96 normal controls. These results enriched the gene mutation spectrum of FRMD7. The authors systematically investigated the clinical phenotype of congenital motor nystagmus in a Chinese population. The study provides further evidence for clinical diagnosis and differential diagnosis and genetic counseling.

The aim of the present study was to evaluate mutations of the G protein-coupled receptor 143 (GPR143) gene for ocular albinism type 1 (OA1) in Chinese patients. For the current study, 8 patients with OA1 were selected from the database of ocular genetic diseases. Genomic DNA of OA1 was prepared from venous leukocytes collected from the patients. Cycle sequencing was used to analyze the exons and adjacent introns of GPR143. The variation detected was analyzed by bidirectional DNA sequencing and further evaluated in 96 controls using heteroduplex‑single strand conformational polymorphism analysis. Additionally, slit lamp photography of anterior segment, fundus photography and optical coherence tomography (OCT) were performed to identify the clinical features of OA1. In five patients with OA1, 5 GPR143 gene mutations were identified and four of them there were novel mutations. The screening rate is 62.5%, including c.333G>A (p.W111X), c.353G>A (p.G118E) (known mutation), C.658+2T>G (splice mutation), c.215&#95;216insCGCTGC (p.71‑72insAA) and c.17T>C (p. L6P). These mutations were absent in the 96 normal controls. Only one patient with OA1 in the present study was female. Patients with OA1 often have congenital nystagmus, refractive error, severe decline of visual acuity (from 0.1 to 0.4) and foveal hypoplasia. Different degrees of pigment loss were evident in the patients' iris and retina, whereas macular structure was not identified in the OCT examination. The findings of the present study expanded the gene mutation spectrum of GPR143 and investigated the clinical phenotype of patients with OA1 in the Chinese population. Additional evidence for clinical diagnosis was provided along with differential diagnosis and genetic counseling.

Purpose: To identify genetic mutations in three families with early onset high myopia (eoHM) limited to female members., Methods: Genomic DNA was collected from participating members of families XF1, XF2, and XF3. Genome-wide linkage scans were performed on the largest family (XF1). Whole exome sequencing was performed on seven samples, including five samples (four affected and one unaffected) from family XF1, as well as the two probands from family XF2 and XF3. Variants were analyzed with multistep bioinformatics analyses. Sanger-dideoxy sequencing was used to verify candidate variations in families and controls., Results: The genome-wide linkage scans performed on family XF1 detected a candidate locus on chromosome Xp11.1-Xq13.3 with a maximum logarithm of the odds (LOD) score of 2.48 and 3.01 for markers DXS991 and DXS986, respectively. Parallel whole exome sequencing identified a novel c.893C>A (p.Ala298Asp) mutation in ARR3 located on Xq13.1 in family XF1, which was shared by all four affected individuals but not the unaffected individual. Two other novel mutations in ARR3 , c.298C>T (p.Arg100*) and c.239T>C (p.Leu80Pro), were detected in families XF2 and XF3, respectively. These mutations were predicted to be damaging and were not present in the normal controls and existing databases. All three mutations cosegregated with eoHM in each of the three families, in which all heterozygous female members are affected whereas all hemizygous male family members are not affected. Transmission of the mutations and eoHM in the three families demonstrates an unusual pattern of X-linked female-limited inheritance., Conclusions: These data suggest that heterozygous mutations in ARR3 might be responsible for X-linked female-limited eoHM in the three families, a pattern contrary to the standard X-linked recessive trait. To our knowledge, eoHM is the first human disease associated with mutations in ARR3 and the second X-linked female-limited disease identified thus far. Identification of ARR3 associated with X-linked female-limited trait provides not only additional evidence of this unusual hereditary pattern but also an additional model for investigating the molecular mechanism responsible for female-limited phenotypes.

Leber congenital amaurosis (LCA) is the most severe form of inherited retinal dystrophy. We have previously performed a mutational analysis of the known LCA-associated genes in probands with LCA by both Sanger and whole exome sequencing. In this study, whole exome sequencing was carried out on 66 new probabds with LCA. In conjunction with these data, the present study provides a comprehensive analysis of the spectrum and frequency of all known genes associated with retinal dystrophy in a total of 159 Chinese probands with LCA. The known genes responsible for all forms hereditary retinal dystrophy were included based on information from RetNet. The candidate variants were filtered by bioinformatics analysis and confirmed by Sanger sequencing. Potentially causative mutations were further validated in available family members. Overall, a total of 118 putative pathogenic mutations from 23 genes were identified in 56.6% (90/159) of probands. These mutations were harbored in 13 LCA-associated genes and in ten genes related to other forms of retinal dystrophy. The most frequently mutated gene in probands with LCA was GUCY2D (10.7%, 17/159). A series of mutational analyses suggests that all known genes associated with retinal dystrophy account for 56.6% of Chinese patients with LCA. A comprehensive molecular genetic analysis of Chinese patients with LCA provides an overview of the spectrum and frequency of ethno-specific mutations of all known genes, as well as indications about other unknown genes in the remaining probands who lacked identified mutations., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Purpose: To identify mutations in COL2A1 and COL11A1 genes and to examine the genotype-phenotype correlation in a cohort of Chinese patients with Stickler syndrome., Methods: A total of 16 Chinese probands with Stickler syndrome were recruited, including nine with a family history of an autosomal dominant pattern and seven sporadic cases. All patients underwent full ocular and systemic examinations. Sanger sequencing was used to analyze all coding and adjacent regions of the COL2A1 and COL11A1 genes. Multiplex ligation-dependent probe amplification was performed to detect the gross indels of COL2A1 and COL11A1. Bioinformatics analysis was performed to evaluate the pathogenicity of the variants., Results: Five mutations in COL2A1 were identified in six of 16 probands, including three novel (c.85C>T, c.3356delG, c.3401delG) mutations and two known mutations (c.1693C>T, c.2710C>T). Of the five mutations, three were truncated mutations, and the other two were missense mutations. Putative pathogenic mutations of the COL11A1 gene were absent in this cohort of patients. Gross indels were not found in COL2A1 or COL11A1 in any of the probands. High myopia was the most frequent initial ocular phenotype of Stickler syndrome. In this study, 12 Chinese probands lacked obvious systemic phenotypes., Conclusions: In this study, three novel and two known mutations in the COL2A1 gene were identified in six of 16 Chinese patients with Stickler syndrome. This is the first study in a cohort of Chinese patients with Stickler syndrome, and the results expand the mutation spectrum of the COL2A1 gene. Analysis of the genotype-phenotype correlation showed that the early onset of high myopia with vitreous abnormalities may serve as a key indicator of Stickler syndrome, while the existence of mandibular protrusion in pediatric patients may be an efficient indicator for the absence of mutations in COL2A1 and COL11A1.

Cone-rod dystrophy (CORD) is a common form of inherited retinal degeneration. Previously, we have conducted serial mutational analysis in probands with CORD either by Sanger sequencing or whole exome sequencing (WES). In the current study, variants in all genes from RetNet were selected from the whole exome sequencing data of 108 CORD probands (including 61 probands reported here for the first time) and were analyzed by multistep bioinformatics analysis, followed by Sanger sequencing and segregation validation. Data from the previous studies and new data from this study (163 probands in total) were summarized to provide an overview of the molecular genetics of CORD. The following potentially pathogenic mutations were identified in 93 of the 163 (57.1%) probands: CNGA3 (32.5%), ABCA4 (3.8%), ALMS1 (3.1%), GUCY2D (3.1%), CACNA1F (2.5%), CRX (1.8%), PDE6C (1.8%), CNGB3 (1.8%), GUCA1A (1.2%), UNC119 (0.6%), RPGRIP1 (1.2%), RDH12 (0.6%), KCNV2 (0.6%), C21orf2 (0.6%), CEP290 (0.6%), USH2A (0.6%) and SNRNP200 (0.6%). The 17 genes with mutations included 12 known CORD genes and five genes (ALMS1, RDH12, CEP290, USH2A, and SNRNP200) associated with other forms of retinal degeneration. Mutations in CNGA3 is most common in this cohort. This is a systematic molecular genetic analysis of Chinese patients with CORD., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Purpose: To investigate mutations in 234 genes associated with retinal dystrophies in a cohort of 298 probands with early-onset high myopia using whole exome sequencing., Methods: Genomic DNA from 298 probands with early-onset high myopia was analyzed by whole exome sequencing. Variants from 234 genes were selected and analyzed by multistep bioinformatics analyses., Results: Systematic analysis of variants in the 234 genes identified potential pathogenic mutations in 34 of 234 genes in 71 of 298 (23.8%) probands. Of the 71 probands, 44 (62.0%) had mutations in 11 genes responsible for ocular diseases accompanied by high myopia, including COL2A1, COL11A1, PRPH2, FBN1, GNAT1, OPA1, PAX2, GUCY2D, TSPAN12, CACNA1F, and RPGR. Initial clinical records of the 71 patients with mutations did not show recognizable signs of original diseases other than high myopia., Conclusions: Mutations in genes known to be responsible for retinal diseases were found in approximately one-fourth of the probands with early-onset high myopia. The high mutation frequency of RetNet genes in these patients can provide clues for genetic screening and further specific clinical examinations of high myopia to promote long-term follow-up assessment and prompt treatment of some diseases.

Purpose: Mutations in 60 known genes were previously identified by exome sequencing in 79 of 157 families with retinitis pigmentosa (RP). This study analyzed variants in 129 genes associated with other forms of hereditary retinal dystrophy in the same cohort., Methods: Apart from the 73 genes previously analyzed, a further 129 genes responsible for other forms of hereditary retinal dystrophy were selected based on RetNet. Variants in the 129 genes determined by whole exome sequencing were selected and filtered by bioinformatics analysis. Candidate variants were confirmed by Sanger sequencing and validated by analysis of available family members and controls., Results: A total of 90 candidate variants were present in the 129 genes. Sanger sequencing confirmed 83 of the 90 variants. Analysis of family members and controls excluded 76 of these 83 variants. The remaining seven variants were considered to be potential pathogenic mutations; these were c.899A>G, c.1814C>G, and c.2107C>T in BBS2; c.1073C>T and c.1669C>T in INPP5E; and c.3582C>G and c.5704-5C>G in CACNA1F. Six of these seven mutations were novel. The mutations were detected in five unrelated patients without a family history, including three patients with homozygous or compound heterozygous mutations in BBS2 and INPP5E, and two patients with hemizygous mutations in CACNA1F. None of the patients had mutations in the genes associated with autosome dominant retinal dystrophy., Conclusions: Only a small portion of patients with RP, about 3% (5/157), had causative mutations in the 129 genes associated with other forms of hereditary retinal dystrophy.

Purpose: To evaluate variants in the LRPAP1, CTSH, LEPREL1, ZNF644, SLC39A5, and SCO2 genes in 298 unrelated patients with early-onset high myopia (eoHM)., Methods: Genomic DNA from 298 patients with eoHM was analyzed by whole exome sequencing. Variants in LRPAP1, CTSH, LEPREL1, ZNF644, SLC39A5, and SCO2 genes were selected and analyzed with bioinformatics. Potential candidate variants were confirmed by Sanger sequencing and then validated in available family members and 192 healthy controls., Results: A total of nine variants predicted to affect the functional residues were detected. The LRPAP1 gene showed a homozygous frameshift mutation (c.199delC, p.Q67Sfs*8) in a consanguineous family. The ZNF644 gene showed five heterozygous missense mutations (c.1106A>T, p.K369M; c.1648G>A, p.A550T; c.2014A>G, p.S672G; c.2048G>C, p.R683T, and c.2551G>C, p.D851H) in five families, but the c.1106A>T, (p.K369M) and c.1648G>A, (p.A550T) in ZNF644 did not co-segregated with high myopia in the families and should be excluded as causative mutations. The SLC39A5 gene showed a heterozygous missense variant (c.1238G>C, p.G413A) in a sporadic individual. The SCO2 gene showed two heterozygous missense variants (c.334C>T, p.R112W and c.358C>T, p.R120W) in two families. None of the variants was detected in 192 healthy controls and all were predicted to be damaging by both Polyphen-2 and SIFT, except for the previously reported p.S672G mutation in ZNF644, which was predicted to be damaging by SIFT but benign by Polyphen-2. No homozygous or compound heterozygous variants were found in CTSH and LEPREL1., Conclusions: Our results provide additional evidence to support the idea that mutation in LRPAP1 is associated with high myopia. Further studies are expected to evaluate the pathogenicity of the variants in CTSH, LEPREL1, ZNF644, SLC39A5, and SCO2., (Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.)

Retinitis pigmentosa (RP) is the most common and highly heterogeneous form of hereditary retinal degeneration. This study was to identify mutations in the 60 genes that were known to be associated with RP in 157 unrelated Chinese families with RP. Genomic DNA from probands was initially analyzed by whole exome sequencing. Sanger sequencing was used to confirm potential candidate variants affecting the encoded residues in the 60 genes, including heterozygous variants from genes that are related to autosomal dominant RP, homozygous or compound heterozygous variants from genes that are related to autosomal recessive RP, and hemizygous variants from genes that are related to X-linked RP. Synonymous and intronic variants were also examined to confirm whether they could affect splicing. A total of 244 candidate variants were detected by exome sequencing. Sanger sequencing confirmed 240 variants out of the 244 candidates. Informatics and segregation analyses suggested 110 potential pathogenic mutations in 28 out of the 60 genes involving 79 of the 157 (50%) families, including 31 (39%, 31/79) families with heterozygous mutations in autosomal dominant genes, 37 (47%, 37/79) families with homozygous (9) or compound heterozygous (28) mutations in autosomal recessive genes, and 11 (14%, 11/79) families with hemizygous mutations in X-linked genes. Of the 110 identified variants, 74 (67%) were novel. The genetic defects in approximately half of the 157 studies families were detected by exome sequencing. A comprehensive analysis of the 60 known genes not only expanded the mutation spectrum and frequency of the 60 genes in Chinese patients with RP, but also provided an overview of the molecular etiology of RP in Chinese patients. The analysis of the known genes also supplied the foundation and clues for discovering novel causative RP genes.

Importance: Mutations in CNGA3 are the most common cause of achromatopsia and cone-rod dystrophies., Objective: To identify CNGA3 mutations in patients with cone dystrophies or Leber congenital amaurosis., Design, Setting, and Participants: Clinical data and genomic DNA in 267 Chinese probands from 138 families with cone dystrophies and 129 families with Leber congenital amaurosis collected at the Zhongshan Ophthalmic Center, Guangzhou, China., Main Outcomes and Measures: Variants in CNGA3 and associated phenotypes, assessed by Sanger sequencing of CNGA3, bioinformatics of variants, and segregation analysis., Results: Homozygous or compound heterozygous mutations in CNGA3, including 26 novel and 13 known mutations, were identified in 46 probands from 138 families with cone dystrophies, but none were found in any of the probands from 129 families with Leber congenital amaurosis. The 46 probands with CNGA3 mutations could be further classified as likely having achromatopsia (18 probands) and cone-rod dystrophies (28 probands) based on electroretinographic recordings. Analysis of family members in 17 of 46 families demonstrated good segregation of the disease with the CNGA3 mutations., Conclusions and Relevance: To our knowledge, this study is the first systemic analysis of CNGA3 in Chinese patients and expands the mutational spectrum and associated phenotypes. Our results suggest that CNGA3 mutations are a common cause of cone-rod dystrophies and achromatopsia in the Chinese population. These data indicate that CNGA3-associated cone dystrophies may be a common form of early-onset severe retinal dystrophies. Therapeutic potential such as gene therapy targeting this gene may benefit some children with early-onset severe retinal dystrophies.

Purpose: To identify the spectrum and frequency of five candidate genes in Chinese patients with congenital ectopia lentis (EL)., Methods: Forty consecutive and unrelated congenital probands with EL were collected and underwent ocular, skeletal, and cardiovascular examinations. Sanger sequencing was used to analyze all of the coding and adjacent regions of five candidate genes: FBN1, ADAMTS10, ADAMTSL4, TGFBR2, and CBS. Mutation analysis was performed to evaluate the pathogenic variants and to identify the cause of congenital EL., Results: The FBN1 gene screen revealed 25 pathogenic variants in 34 of the 40 families with congenital EL, including three novel (c.1955G>T, c.2222delA, and c.4381T>C) and 22 known mutations. The ADAMTSL10 gene screen revealed a compound heterozygous variant (c.1586G>A and c.2485T>A) in a family with Weill-Marchesani syndrome (WMS). In the remaining five probands, no pathogenic variant was detected in any of the five screened genes., Conclusions: In this study, we identified three novel and 22 known mutations in FBN1 in 34 of 40 EL families. The results expand the mutation spectrum of the FBN1 gene and suggest that FBN1 mutations may be the major cause of congenital EL in Chinese patients.

Purpose: To evaluate mutations in the MYOC, WDR36, OPTN, OPA1, NTF4, CYP1B1, and LTBP2 genes in a cohort of Chinese patients with primary glaucoma., Methods: Genomic DNA was prepared from 683 unrelated patients, including 50 with primary congenital glaucoma, 104 with juvenile open-angle glaucoma (JOAG), 186 with primary open-angle glaucoma (POAG), and 343 with primary angle-closure glaucoma (PACG). Mutations in the seven genes in 257 patients (36 with JOAG, 89 with POAG, and 132 with PACG) were initially analyzed by exome sequencing and then confirmed by Sanger sequencing. In addition, Sanger sequencing was used to detect MYOC mutations in the remaining 426 patients., Results: Exome sequencing identified 19 mutations (6 in MYOC, 9 in WDR36, 3 in OPA1, and 1 in OPTN) in 20 of 257 patients, including 4 patients with JOAG, 8 patients with POAG, and 8 patients with PACG. No mutation was detected in the other three genes. In addition, Sanger sequencing detected additional MYOC mutations in 5 of the remaining 426 patients, including 3 patients with JOAG and 2 patients with POAG., Conclusions: Twenty-two mutations in MYOC, WDR36, OPA1, and OPTN were detected in 25 of the 683 patients with primary glaucoma, including nine MYOC mutations in 11 patients, nine WDR36 mutations in 11 patients, three OPA1 mutations in 3 patients, and one OPTN mutation in a patient who also carried a MYOC mutation. Eight mutations in MYOC, WDR36, and OPA1 in 8 of the 343 PACG patients are of uncertain significance and need to be analyzed further., (Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.)

Objective: The goal of this study was to identify mutations in 25 known causative genes in 47 unrelated Chinese families with cone-rod dystrophy (CORD)., Methods: Forty-seven probands from unrelated families with CORD were recruited. Genomic DNA prepared from leukocytes was analyzed by whole exome sequencing. Variants in the 25 genes were selected and then validated by Sanger sequencing., Results: Fourteen potential pathogenic mutations, including nine novel and five known, were identified in 10 of the 47 families (21.28%). Homozygous, compound heterozygous, and hemizygous mutations were detected in three, four, or three families, respectively. The 14 mutations in the 10 families were distributed among CNGB3 (three families), PDE6C (two families), ABCA4 (one family), RPGRIP1 (one family), RPGR (two families), and CACNA1F (one family)., Conclusions: This study provides a brief view on mutation spectrum of the 25 genes in a Chinese cohort with CORD. Identification of novel mutations enriched our understanding of variations in these genes and their associated phenotypes. To our knowledge, this is the first systemic exome-sequencing analysis of all of the 25 CORD-associated genes.

Purpose: Dominant optic atrophy (DOA) is the most common form of autosomal inherited optic neuropathy, mainly caused by mutations in the optic atrophy 1 (OPA1) gene. The purpose of this study was to detect OPA1 gene mutations and associated phenotypes in Chinese patients with suspected hereditary optic neuropathy., Methods: A cohort of 193 Chinese families with suspected hereditary optic neuropathy was collected, which had been excluded from the three common primary mitochondrial DNA mutations associated with Leber hereditary optic neuropathy in our prior screening. Sanger sequencing was used to analyze variants in the coding and adjacent regions of OPA1., Results: In this study, 11 heterozygous OPA1 mutations, among which eight were novel and three were known, were identified in 12 of the 193 families (6.2%) but in none of the 192 control individuals. These novel mutations consisted of two nonsense mutations (p.E707* and p.K797*), two missense mutations (p.T330S and p.V377I), two deletions (p.S64fs and p.L331fs), one small insertion (p.L17fs), and one splice site mutation (c.2614-2A>G). Of the 12 families, three had a family history of optic neuropathy while nine were sporadic cases. Analysis of the family members in the two sporadic cases demonstrated that one parent in each of the two families had the OPA1 mutation and mild phenotype of optic atrophy. A 4-year-old boy with severe ocular phenotype was found to be compound heterozygous for two OPA1 mutations, a p.S64fs frameshift deletion and a p.V377I missense mutation, possibly implying an additive effect., Conclusions: This study implies that the frequency of DOA is much lower than that of Leber hereditary optic neuropathy in Chinese compared with other ethnic groups. Lack of awareness of the mild phenotype of DOA may contribute to the low frequency of OPA1-related DOA in Chinese. The phenotype associated with compound heterozygous OPA1 mutations may suggest a possible addictive effect.

Background: Leber hereditary optic neuropathy (LHON) is a mitochondrial disorder with gender biased and incomplete penetrance. The majority of LHON patients are caused by one of the three primary mutations (m.3460G > A, m.11778G > A and m.14484T > C). Rare pathogenic mutations have been occasionally reported in LHON patients., Methods: We screened mutation m.10680G > A in the MT-ND4L gene in 774 Chinese patients with clinical features of LHON but lacked the three primary mutations by using allele specific PCR (AS-PCR). Patients with m.10680G > A were further determined entire mtDNA genome sequence., Results: The optimal AS-PCR could detect as low as 10% heteroplasmy of mutation m.10680G > A. Two patients (Le1263 and Le1330) were identified to harbor m.10680G > A. Analysis of the complete mtDNA sequences of the probands suggested that they belonged to haplogroups B4a1 and D6a1. There was no other potentially pathogenic mutation, except for a few private yet reported variants in the MT-ND1 and MT-ND5 genes, in the two lineages. A search in reported mtDNA genome data set (n = 9277; excluding Chinese LHON patients) identified no individual with m.10680G > A. Frequency of m.10680G > A in Chinese LHON patients analyzed in this study and our previous studies (3/784) was significantly higher than that of the general populations (0/9277) (P = 0.0005)., Conclusion: Taken together, we speculated that m.10680G > A may be a rare pathogenic mutation for LHON in Chinese. This mutation should be included in future clinical diagnosis.

Mitochondrial transfer RNA (mt-tRNA) mutations have been reported to be associated with a variety of diseases. In a previous paper that studied the mtDNA background effect on clinical expression of Leber's hereditary optic neuropathy (LHON) in 182 Chinese families with m.11778G>A, we found a strikingly high frequency (7/182) of m.593T>C in the mitochondrially encoded tRNA phenylalanine (MT-TF) gene in unrelated LHON patients. To determine the potential role of m.593T>C in LHON, we compared the frequency of this variant in 479 LHON patients with m.11778G>A, 843 patients with clinical features of LHON but without the three known primary mutations, and 2374 Han Chinese from the general populations. The frequency of m.593T>C was higher in LHON patients (14/479) than in suspected LHON subjects (12/843) or in general controls (49/2374), but the difference was not statistically significant. The overall penetrance of LHON in families with both m.11778G>A and m.593T>C (44.6%) was also substantially higher than that of families with only m.11778G>A (32.9%) (P = 0.083). Secondary structure prediction of the MT-TF gene with the wild type or m.593T>C showed that this nucleotide change decreases the free energy. Electrophoretic mobility of the MT-TF genes with the wild type or m.593T>C transcribed in vitro further confirmed the change of secondary structure in the presence of this variant. Although our results could suggest a modest synergistic effect of variant m.593T>C on the LHON causing mutation m.11778G>A, the lack of statistical significance probably due to the relatively small sample size analyzed, makes necessary more studies to confirm this effect.

Leber hereditary optic neuropathy (LHON) is the most common cause of sudden blindness in young adults and is caused by mtDNA mutations. At least 30 mutations have been identified but only the three common mutations (m.3460G>A, m.11778G>A, and m.14484T>C) have been extensively studied. Most other mutations, including m.3635G>A, are considered as potential candidate LHON mutations due to a lack of enough evidence. The frequency of these potential candidate mutations in populations has not been determined. In this study, we performed a comprehensive survey of m.3635G>A in 1398 unrelated probands suspected to have LHON and detected the m.3635G>A mutation in 8 cases, including 4 probands with a family history of LHON. The mutation in 7 cases was homoplasmic, but the mutation in one patient was heteroplasmic. Patients with the m.3635G>A mutation demonstrated the typical phenotype of LHON. Our results provide strong evidence that similar to m.3460G>A, m.3635G>A is a pathogenic and common LHON mutation in the Chinese population., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Purpose: To identify novel mutation in the PAX6 (paired box gene 6) gene and characterize new clinical features of severe ocular malformation in a Chinese patient with Peters' anomaly., Methods: A 10-month-old male infant, who presented with corneal opacity and nystagmus, was referred to our pediatric clinic and underwent a complete general physical and ophthalmological examination, including anterior segment and retinal evaluation with slit-lamp microscopy, an A/B ultrasonic scan, and electroretinography (ERG). Genomic DNA was prepared from venous leukocytes. The coding regions and the adjacent intronic sequence of PAX6 were amplified by a polymerase chain reaction, and subsequently analyzed by direct sequencing. The variation detected was further evaluated in 100 controls using heteroduplex- single strand conformational polymorphism (SSCP) analysis., Results: The patient had bilateral Peters' anomaly showing congenital nystagmus, corneal leukoma with anterior synechia, anterior polar cataract, and his pupils could not be dilated because of posterior synechia. Electroretinography (ERG) demonstrated retina hypogenesis and an A/B ultrasonic scan showed microphthalmus. A novel mutation: C.51C>A (P. N17K) was identified in PAX6 while this mutation was absent in 100 normal controls. This mutation, which affects highly conserved amino acid, has not been previously reported., Conclusions: PAX6 mutations cause ocular malformations that vary considerably in pattern and severity. In this study, we identified one novel mutation in PAX6 in a patient with severe ocular clinical features of Peters' anomaly. This finding expands the mutation spectrum in PAX6 and enriches our knowledge of genotype-phenotype relations due to PAX6 mutations.

Purpose: To test the association of the X-chromosome regions (Xp21.1-q21.2 and Xq25-27.2) with Leber hereditary optic neuropathy (LHON) in Chinese patients., Methods: One hundred and seventy-five male LHON patients with the G11778A mutation and 100 unrelated normal males participated. Twelve microsatellite markers and four single-nucleotide polymorphisms (SNPs) were genotyped for patients and controls. A chi(2) or Fisher's exact test was used to compare the frequencies of genotypes as well as haplotypes in the two groups., Results: Significant differences between patients and controls were found in two isolated microsatellite markers (DXS6803: chi(2)=37.17, p=2.45 x 10(-5); DXS984: chi(2)=33.88, p=1.66 x 10(-6)) based on genotype frequencies. However, no significant differences for genotype and haplotype frequencies were found in the other 14 markers located in the two reported regions of Xp21.1-q21.2 and Xq25-27.2., Conclusions: Our results provide suggestive evidence of X-linked modifiers on the expression of LHON. Further studies are needed to identify the exact nuclear genes that might affect LHON expression.

Leber hereditary optic neuropathy (LHON) was the first disease to be linked to the presence of a mitochondrial DNA (mtDNA) mutation. Nowadays over 95% of LHON cases are known to be caused by one of three primary mutations (m.11778G>A, m.14484T>C, and m.3460G>A). Reports for other (rare) primary mutations in LHON patients are not infrequent. Among those is the mutation m.3635G>A in the MT-ND1 gene which was reported to be pathogenic in a Russian LHON family. In this study, we report on a Chinese family with clinical features of LHON but without any of the three well-known primary mutations. Analysis of the complete mitochondrial genome in the proband revealed the presence of m.3635G>A and m.6228C>T, along with a full array of other variants that suggest the haplogroup M7b1. Evolutionary analysis indicates that site 3635, but not 6228, is highly conserved in vertebrates. Protein secondary-structure modeling for the MT-ND1 protein harboring amino acid change S110N indicates that mutant m.3635G>A decreases the protein hydrophobicity. Our current observations provide further support for a pathogenic role of m.3635G>A in patients with LHON.

Purpose: This study was conducted to investigate the mutation spectrum of the cytochrome P450 gene (CYP1B1) in Chinese patients with primary congenital glaucoma (PCG)., Methods: The coding regions of CYP1B1 from 41 Chinese PCG patients were analyzed using polymerase chain reaction (PCR) and heteroduplex analysis-single strand conformation polymorphism (HA-SSCP) followed by subsequent cloning and bidirectional sequencing. New variants were confirmed by restriction fragment length polymorphism (RFLP) analysis in 80 normal Chinese controls., Results: Six distinct mutations, four of which are novel, were identified in 14.6% (6/41) of all patients. The CYP1B1 mutations in two patients were homozygous, and the other four patients were compound heterozygous. Beyond the four novel mutations (g.4531&#95;4552del22bp, g.4633delC, p.S336Y, and p.I471S), two reported missense mutations (R469W and R390H) were also identified. The missense mutation, R390H, was involved in 9.8% (4/41) of patients in our study. None of the novel mutations was observed in any of the 80 controls., Conclusions: Our results support the premise that CYP1B1 is a major gene for PCG, appearing to be responsible for the disease in roughly one in six Chinese PCG patients. The R390H mutation was identified as a predominant CYP1B1 allele among the Chinese PCG patients in our study. This observation emphasizes the importance of mutational screening of CYP1B1, especially for the R390H mutation in Chinese patients.

Leber hereditary optic neuropathy (LHON) is the most extensively studied mitochondrial disease, with the majority of the cases being caused by one of three primary mitochondrial DNA (mtDNA) mutations. Incomplete disease penetrance and gender bias are two features of LHON and indicate involvement of additional genetic or environmental factors in the pathogenesis of the disorder. Haplogroups J, K, and H have been shown to influence the clinical expression of LHON in subjects harboring primary mutations in European families. However, whether mtDNA haplogroups would affect the penetrance of LHON in East Asian families has not been evaluated yet. By studying the penetrance of LHON in 1859 individuals from 182 Chinese families (including one from Cambodia) with the m.11778G-->A mutation, we found that haplogroup M7b1'2 significantly increases the risk of visual loss, whereas M8a has a protective effect. Analyses of the complete mtDNA sequences from LHON families with m.11778G-->A narrow the association of disease expression to m.12811T-->C (Y159H) in the NADH dehydrogenase 5 gene (MT-ND5) in haplogroup M7b1'2 and suggest that the specific combination of amino acid changes (A20T-T53I) in the ATP synthase 6 protein (MT-ATP6) caused by m.8584G-->A and m.8684C-->T might account for the beneficial background effect of M8a. Protein secondary-structure prediction for the MT-ATP6 with the two M8a-specific amino acid changes further supported our inferences. These findings will assist in further understanding the pathogenesis of LHON and guide future genetic counseling in East Asian patients with m.11778G-->A.

Co-occurrence of double pathogenic mtDNA mutations with different claimed pathological roles in one mtDNA is infrequent. It is tentative to believe that each of these pathogenic mutations would have its own deleterious effect. Here we reported one three-generation Chinese family with a high penetrance of LHON (78.6%). Analysis of the complete mitochondrial genome in the proband revealed the presence of the LHON primary mutation G11778A in the NADH dehydrogenase 4 (ND4) gene and a deafness-associated mutation A1555G in the 12S rRNA gene. The other mtDNA variants in this family suggested a haplogroup status G2b. Although A1555G has long been confirmed to be a primary mutation for aminoglycoside-induced and non-syndromic hearing loss, none of the maternally related members in this family showed hearing impairment. It thus seems that the occurrence of A1555G in this family had no pathological manifestation. However, whether A1555G has a synergistic effect with G11778A and contribute to the high penetrance of LHON remained an open question. To our knowledge, this is the first report that identified the co-existence of a deafness mutation A1555G and a primary LHON mutation G11778A in one family.

The penetrance of Leber's hereditary optic neuropathy (LHON) in families with primary mitochondrial DNA (mtDNA) mutations is very complex. Matrilineal and nuclear genetic background, as well as environmental factors, have been reported to be involved in different affected pedigrees. Here we describe two large Chinese families that show a striking difference in the penetrance of LHON, in which 53.3% and 15.0% of members were affected (P<0.02), respectively. Analysis of the complete mtDNA genome of the two families revealed the presence of the primary mutation G11778A and several other variants suggesting the same haplogroup status G2a. The family with higher penetrance contained a previously described secondary mutation G13708A, which presents a polymorphism in normal Chinese samples and does not affect in vivo mitochondrial oxidative metabolism as described in a previous study. Evolutionary analysis failed to indicate any putatively pathogenic mutation that cosegregated with G11778A in these two pedigrees. Our results suggest that the variable penetrance of LHON in the two Chinese families is independent of both their mtDNA haplotype background and a secondary mutation G13708A. As a result, it is likely that unknown nuclear gene involvement and/or other factors contribute to the strikingly different penetrance of LHON.

Purpose: There are few genetic studies and clinical descriptions of Asian patients with X-linked ocular albinism (OA1). In the present study, the mutation analysis of G protein-coupled receptor 143 gene (GPR143) and clinical characteristics were assessed in Chinese patients with OA1., Methods: Six families with OA1 were recruited from our pediatric and genetic eye clinic. Genomic DNA was prepared from venous leukocytes. The coding regions of GPR143 were amplified by polymerase chain reaction, and subsequently analyzed by direct sequencing. The variations detected were further evaluated in available family members as well as controls., Results: Mutations in GPR143 were identified in each of the six families: c.849delT (p.Val284SerfsX15); c.238&#95;240delCTC (p.Leu80del); c.658+1G>A, c.353G>A (p.Gly118Glu); g.1103&#95;7266del6164 (p.Gly84AlafsX65), which resulted in a deletion of exons 2 and 3; and g.25985&#95;26546del562 (p.Gly296ValfsX26), which resulted in a deletion of exon 8. Of these six, c.353G>A is a known mutation, while the other five are novel. All affected patients had nystagmus, poor visual acuity, and foveal hypoplasia. However, hypopigmentation of the iris and fundus was very mild in these patients., Conclusions: Five novel mutations and one known mutation were identified in six Chinese families with OA1. These results expand the mutation spectrum of GPR143, and demonstrate the clinical characteristics of OA1 among the Chinese.

Purpose: High myopia is a common genetic variant that severely affects vision. Genes responsible for myopia without linked additional functional defects have not been identified. Mutations in the nyctalopin gene (NYX) located at Xp11.4 are responsible for a complete form of congenital stationary night blindness (CSNB1). High myopia is usually observed in patients with CSNB1. This study was designed to test the possibility that mutations in the NYX gene might cause high myopia without congenital stationary night blindness (CSNB)., Methods: The genomic sequence of NYX in 52 male probands with high myopia but without CSNB was analyzed through direct DNA sequencing. Variations in the NYX were verified by analyzing available family members and 232 controls., Results: Two unrelated male individuals with high myopia but without night blindness were found to have novel Cys48Trp and Arg191Gln mutations in NYX. The mutations were found to be located in distinct regions, different from the locations of mutations known to cause congenital stationary night blindness with myopia (CSNB1)., Conclusions: Mutations in NYX may cause high myopia without CSNB. The observations suggest that NYX may have independent effects on myopia and night blindness.

Purpose: The 208delG (c.72delG, p.Thr25GlnfsX120) mutation in the FSCN2 gene was reported to cause autosomal dominant retinitis pigmentosa (ADRP) and autosomal dominant macular degeneration (ADMD). The purpose of this study was to detect the 208delG mutation in Chinese individuals, with or without hereditary retinal degeneration., Methods: DNA fragments encompassing the 208delG mutation were amplified by polymerase chain reaction (PCR). The amplicons were analyzed by sequencing or/and heteroduplex- single-strand conformational polymorphism (SSCP) analysis. An ophthalmic evaluation was conducted in those individuals with the 208delG mutation., Results: The 208delG mutation was detected in 8 of 242 unrelated probands: 175 with retinitis pigmentosa (RP), 20 with Leber congenital amaurosis (LCA), and 47 with cone-rod dystrophy (CORD). Of the eight, the retinal diseases were RP in six probands, LCA in one proband, and CORD in one proband. The disease was transmitted as an autosomal dominant (one family), autosomal recessive (two families), or sporadic (five families) trait. The mutation did not cosegregate with retinal degeneration in three families, whereas five normal family members also had the mutation. In addition, this mutation was also detected in 13 of 521 unrelated control subjects., Conclusions: The 208delG mutation in FSCN2 is not associated with hereditary retinal degeneration in the Chinese individuals examined, which contradicts the original report about mutation in FSCN2 as a cause of ADRP and ADMD. This finding reminds us that great care is needed in making mutation-disease associations.

Purpose: Mutations in PAX6 are the major cause of aniridia. Only a few PAX6 mutations in Chinese have been reported. This study is to identify novel mutations in PAX6 of Chinese patients with aniridia., Methods: Aniridia patients were collected from 11 Chinese families, and genomic DNA was prepared from venous leukocytes. The coding regions of PAX6 were analyzed by direct sequencing of PCR products. Variations detected were further evaluated in available family members as well as in controls by using heteroduplex-SSCP analysis., Results: Four novel mutations including c.141+1G>A, c.184-3C>G, c.542C>A (Ser181X), and c.562C>T (Gln188X) and one known mutation c.120C>A (Cys40X) were identified in PAX6 of five unrelated patients with aniridia. All five mutations are expected to generate null alleles of PAX6. Varied ocular phenotypes were observed in different patients within families., Conclusions: We identified four novel mutations and 1 known mutation in the human PAX6 gene. These results expand the mutation spectrum in PAX6 and enrich our knowledge of genotype-phenotype relation due to PAX6 mutations.

We report the molecular epidemiology of three primary mutations in mitochondrial DNA (mtDNA) responsible for Leber hereditary optic neuropathy (LHON) based on analysis of probands suspected with LHON from 903 Chinese families. Most of them had optic neuropathy of unknown cause, and only 128 had a family history of optic neuropathy. Mutations in the mtDNA were detected in 346 probands. Of the 346 cases, 340 were homoplasmic and only six were heteroplasmic; 284 were male and 62 were female; 120 had a family history and 226 were sporadic. G11778A, T14484C and G3460A mutations were detected in 312 (90.2%), 30, and four families, respectively. The majority (226/346, 65.3%) of all LHON cases in Chinese are sporadic. These 226 probands (29.2%) were identified from 775 probands with sporadic optic neuropathy. Affected male-to-female ratio was 4.6:1 for all probands but was 2.2:1 for family members. Average age at onset was 18.5 years, ranging from 4.5 to 47 years old.

X-linked congenital stationary night blindness (CSNB) and NYX mutation have not been reported in Chinese. Here, two Chinese families with the complete form of CSNB (CSNB1) are presented. Linkage analysis of one family mapped the disease to Xp11-Xq13 where NYX is located. Sequence analysis of NYX identified two novel mutations, c.281G>C and c.302T>C, which would result in missense changes of p.Arg94Pro and p.Ile101Thr in the encoded protein. These two mutations were not found in 96 controls. The c.281G>C mutation cosegregated with nyctalopia and myopia. Our results expand the mutation spectrum of NYX and enrich the clinical information related to NYX mutation. The importance of associated myopia with NYX mutations is discussed.

Purpose: To describe the clinical characteristics of a Y-sutural cataract associated with myopia in a large Chinese family and to identify the causative gene and mutation., Methods: An autosomal dominant Y-sutural cataract and myopia were identified in members of a large family of Han ethnicity living in southern China. Ophthalmological examinations were performed and a medical history was taken. Blood samples were collected for DNA isolation. A genome wide scan was performed using markers spaced at about 10 cM intervals for genotyping and two point linkage analysis. Candidate genes were sequenced., Results: Bilateral lens opacities, the only sign of cataract in early childhood and the most prominent sign in all affected individuals, involved the entire anterior Y and posterior inverted Y sutures, showing a feather duster like appearance. The Y-sutural cataract in this family mapped to an 11.4 cM (13.5 Mb) region between D3S3606 and D3S1309 on chromosome 3q22 with a maximum lod score of 5.7 at theta=0 for D3S1292. Sequence analysis of the beaded filament structural protein 2 (BFSP2) gene identified a previously described c.697&#95;699delGAA (E233del) mutation which was present in all individuals with Y-sutural cataract but not in unaffected individuals and controls. Myopia, observed in 10 out of 12 cataract patients and significantly higher than that in unaffected offspring and siblings (1 out of 8), was independently mapped to a 61.2 cM (59 Mb) region between D3S3606 and D3S1262 on 3q21.3-q27.2 with maximum lod score of 3.79., Conclusions: This Y-sutural cataract is caused by an E233del mutation in BFSP2 which provides additional evidence supporting mutations in BFSP2 as a cause for cataract and demonstrates phenotypic variability in cataracts caused by BFSP2. The Y-sutural opacity in the lens might be the typical and earliest sign for cataract caused by the BFSP2 mutation. In addition, these results demonstrate a myopia susceptibility locus in this region, which might also be associated with the mutation in BFSP2.

Leber hereditary optic neuropathy (LHON) and dominant optic atrophy (DOA), the most common forms of hereditary optic neuropathy, are easily confused, and it is difficult to distinguish one from the other in the clinic, especially in young children. The present study was designed to survey the mutation spectrum of common pathogenic genes (OPA1, OPA3 and mtDNA genes) and to analyze the genotype-phenotype characteristics of Chinese patients with suspected childhood-onset hereditary optic neuropathy. Genomic DNA and clinical data were collected from 304 unrelated Chinese probands with suspected hereditary optic neuropathy with an age of onset below 14 years. Sanger sequencing was used to screen variants in the coding and adjacent regions of OPA1, OPA3 and the three primary LHON-related mutation sites in mitochondrial DNA (mtDNA) (m.3460G>A, m.11778G>A and m.14484T>C). All patients underwent a complete ophthalmic examination and were compared with age-matched controls. We identified 89/304 (29.3%) primary mtDNA mutations related to LHON in 304 probands, including 76 mutations at m.11778 (76/89, 85.4% of all mtDNA mutations), four at m.3460 (4/89, 4.5%) and nine at m.14484 (9/89, 10.1%). This result was similar to the mutation frequency among Chinese patients with LHON of any age. Screening of OPA1 revealed 23 pathogenic variants, including 11 novel and 12 known pathogenic mutations. This study expanded the OPA1 mutation spectrum, and our results showed that OPA1 mutation is another common cause of childhood-onset hereditary optic neuropathy in Chinese pediatric patients, especially those with disease onset during preschool age. [ABSTRACT FROM AUTHOR]

Abstract: Ten mutations in the guanylate cyclase activator 1A (GUCA1A) have been previously identified and reported in patients with retinal degeneration, including patients from 12 families with cone-rod dystrophy (CORD) and in an isolated patient with retinitis pigmentosa (RP). In this study, the coding exons and adjacent regions of GUCA1A were evaluated in 130 probands with CORD from 130 unrelated Chinese families using Sanger sequencing. A novel heterozygous c.464A>C (p.Glu155Ala) mutation was detected in a proband from a large family. The mutation presented in all nine patients examined in that family, but it was absent in six unaffected family members and 192 normal controls. All the nine patients in that family expressed typical CORD in eight cases and atypical CORD in one case. The results of this study suggested that the GUCA1A mutation only contributes to a small portion of CORD in people of Chinese descent. [Copyright &y& Elsevier]

Abstract: Mutations in the cone–rod homeobox gene (CRX) are associated with cone–rod dystrophy (CORD), Leber congenital amaurosis (LCA), and, in rare cases, retinitis pigmentosa (RP). In this study, three variations were detected in 3 of 130 families with CORD, including two novel mutations, c.239A>G (p.Glu80Gly) and c.362C>T (p.Ala121Val). So far, 49 mutations in CRX were reported, affecting about 2.35% of LCA, 4.76% of CORD, and 0.80% of RP. These mutations can be classified as missense (38.78%), nonsense (4.08%), deletion (36.73%), insertion (16.33%), and indel (4.08%). They distributed in the three coding exons without mutation hot spots. No clear genotype–phenotype correlation could be established so far. [Copyright &y& Elsevier]