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Purpose: The PROM1 p.Arg373Cys variant has been reported to cause dominant Stargardt disease, cone-rod dystrophy, and occasionally retinitis pigmentosa. This study aimed to evaluate the common phenotype associated with this variant in Chinese patients., Methods: Variants in PROM1 were collected from in-house exome data. Potential pathogenic variants were selected, verified, and then confirmed by Sanger sequencing and co-segregation analysis. Ocular phenotypes were reviewed and further clarified by ophthalmologic examinations., Results: The heterozygous c.1117C>T (p.Arg373Cys) variant was identified in four unrelated families, and biallelic variants were detected in three families. Of the 10 patients from four families with the p.Arg373Cys variant, six patients from three families who underwent full fundus examination demonstrated various degrees of macular dystrophy, as well as typical bone-spicule pigment deposits in the peripheral retina. The remaining four patients did not undergo a full dilated fundus examination. A relatively preserved zone was observed between the macular and peripheral lesions. Electroretinography results showed cone and rod involvement in three patients., Conclusions: Unlike Stargardt disease alone, which was considered to be the main phenotype of the p.Arg373Cys variant, all patients with full-field fundus examination in our study presented with macular dystrophy plus peripheral retinopathy resembling retinitis pigmentosa. Different phenotypes associated with the p.Arg373Cys variant may actually reflect different stages of the same disease: a predominant central cone phenotype at an early stage and peripheral rod involvement as degeneration progresses. Evaluation of the full fundus, especially the peripheral region in additional patients, is expected to confirm our findings.

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_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.

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., Competing Interests: The authors have declared that no competing interests exist.

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.

Purpose: Mutations in MFRP have been reported to cause autosomal recessive posterior microphthalmia, nanophthalmos, and an ophthalmic syndrome characterized by posterior microphthalmia, high hyperopia, retinitis pigmentosa, foveoschisis, and optic disc drusen. High hyperopia is a consistent sign of this syndrome. The purpose of this study was to detect MFRP mutations in 46 unrelated Chinese probands with high hyperopia., Methods: Clinical data and genomic DNA were collected from 46 Chinese probands diagnosed as having high hyperopia. Genomic DNA from 42 probands was initially analyzed by whole exome sequencing. MFRP variants were confirmed by Sanger sequencing. The coding sequence of MFRP for four additional probands was also analyzed by Sanger sequencing. Candidate MFRP variants were further validated in available family members and 192 normal individuals., Results: Potential pathogenic compound heterozygous mutations, including c.287_291del (p.P96Lfs*6), c.1615C>T (p.R539C), c.664C>A (p.P222T), c.1150dup (p.H384Pfs*8), and c.1549C>T (p.R517W), were detected in three of the 46 probands included in this study. The clinical data revealed that all patients in this study had high hyperopia of +13.50D or higher and an eye axial length of 16.78 mm or less. Electroretinography showed normal responses in a patient with missense mutations and reduced rod responses in another patient with missense and truncation mutations in whom optical coherence tomography showed developmental cystoid macular degeneration in both eyes., Conclusions: The current study expands our knowledge of the mutation spectrum of MFRP and its associated phenotypes. To our knowledge, this is the first report of MFRP mutations in a Chinese cohort.

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: Mouse serine protease 56 (Prss56) mutants show a phenotype of angle-closure glaucoma with a shortened ocular axial length. Mutations in the human PRSS56 gene are associated with posterior microphthalmia and nanopthalmos. In this study, variations in PRSS56 were evaluated in patients with either primary angle-closure glaucoma (PACG) or high hyperopia., Methods: A total of 561 participants were enrolled in this study, including 189 individuals with PACG, 110 individuals with simple high hyperopia (sphere refraction ≥+5.00 D), and 262 normal control subjects (-0.5 D

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 © 2013 Elsevier Ireland Ltd. All rights reserved.)

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.

Purpose: The majority of Leber hereditary optic neuropathy (LHON) cases are caused by one of three mitochondrial DNA (mtDNA) primary mutations (m.3460G>A, m.11778G>A, and m.14484T>C). In recent studies, we and others have shown that mutation m.3635G>A is a primary LHON mutation, particularly in Chinese. The purpose of this study was to perform a thorough analysis for the complete mtDNA genome sequence variation in Chinese patients with m.3635G>A and to identify potentially functional variants cosegregated with m.3635G>A., Methods: The complete mtDNA genomes of five Chinese patients with LHON carrying m.3635G>A were determined. A phylogenetic tree was constructed to distinguish the private and ancestral mtDNA variants in each lineage. Previously unreported variants in each mtDNA were defined with a web-based and database search. mtDNA variants that changed the structure of the membrane-spanning region of the protein were also evaluated, together with evolutionary conservation analysis, to predict their potential pathogenicity., Results: The five patients with LHON sequenced in this study belonged to haplogroups M7b4 (Le131), F1a (Le329 and Le337), B5b (Le569), and M7b6 (Le834), which suggested multiple origins of m.3635G>A. Private variants m.12811T>C, m.14063T>C, m.15237T>C, and m.9071C>T in these patients were predicted to change the structure of the membrane-spanning region of the respective proteins., Conclusions: Mutation m.3635G>A had multiple origins in Chinese patients with LHON. We also identified several potentially functional variants cosegregated with m.3635G>A.

Purpose: A genome-wide association study (GWAS) of high myopia found that five single nucleotide polymorphisms (SNPs) in 4q25 were associated with high myopia. The original study suggested replication studies were needed to validate these results. The aim of our study was to examine if these SNPs are associated with myopia in a different set of samples., Methods: Genomic DNA was collected from 2307 unrelated individuals, including 1052 university students without myopia and 1255 university students with myopia (615 students with moderate myopia and 640 students with high myopia). Four of the five reported SNPs at 4q25, rs2218817, rs10034228, rs1585471 and rs6837348, were genotyped using SNaPshot. The genotype and allele frequencies of the SNPs between myopias and controls were compared by chi-squared test., Results: Genotype and allele frequencies of the four SNPs showed significant differences between the myopia and control groups (rs2218817: genotype p = 0.009, OR = 1.18; rs10034228: genotype p = 0.009, OR = 1.18; rs1585471: genotype p = 0.007, OR = 1.19 and rs6837348: genotype p = 0.012, OR = 1.18)., Conclusions: Our results support the association between the four SNPs and myopia, suggesting a myopia predisposing locus at 4q25 that deserves further study., (Ophthalmic & Physiological Optics © 2011 The College of Optometrists.)

Purpose: To identify the genetic defect in a large Chinese family with autosomal dominant cerulean cataract., Methods: Genomic DNA and clinical data were collected from the family. Candidate gene sequencing and genome-wide linkage analysis were used to disclose the molecular basis responsible for cerulean cataract in the family., Results: Initially, sequencing analysis of the three genes (beta-B2-crystallin [CRYBB2], gamma-D-crystallin [CRYGD], and V-MAF avian musculoaponeurotic fibrosarcoma oncogene homolog [MAF]) known to cause cerulean cataract failed to find any mutation. Then, genome-wide linkage analysis mapped the disease to chromosome 12q13-q22 between D12S85 and D12S351, with a maximum lod score of 4.10 at θ=0. Sequence analysis of the major intrinsic protein of lens fiber gene (MIP), a gene known to cause other types of cataract in the linkage interval, detected a novel heterozygous initiation codon mutation, c.2T>C (p.Met1?). This mutation was present in all patients with cerulean cataract but was not present in any of the 13 unaffected family members nor in 96 control individuals., Conclusions: Cerulean cataract was found in a large family and is caused by a novel initiation codon mutation in MIP. This study adds a new member in the existing list of genes causing cerulean cataract and expands the mutation spectrum and phenotypic association of MIP mutations.

Background: Leber congenital amaurosis (LCA) is the earliest onset and most severe form of hereditary retinal dystrophy. So far, full spectrum of variations in the 15 genes known to cause LCA has not been systemically evaluated in East Asians. Therefore, we performed comprehensive detection of variants in these 15 genes in 87 unrelated Han Chinese patients with LCA., Methodology/principal Findings: The 51 most frequently mutated exons and introns in the 15 genes were selected for an initial scan using cycle sequencing. All the remaining exons in 11 of the 15 genes were subsequently sequenced. Fifty-three different variants were identified in 44 of the 87 patients (50.6%), involving 78 of the 88 alleles (11 homozygous and 56 heterozygous variants). Of the 53 variants, 35 (66%) were novel pathogenic mutations. In these Chinese patients, variants in GUCY2D are the most common cause of LCA (16.1% cases), followed by CRB1 (11.5%), RPGRIP1 (8%), RPE65 (5.7%), SPATA7 (4.6%), CEP290 (4.6%), CRX (3.4%), LCA5 (2.3%), MERTK (2.3%), AIPL1 (1.1%), and RDH12 (1.1%). This differs from the variation spectrum described in other populations. An initial scan of 55 of 215 PCR amplicons, including 214 exons and 1 intron, detected 83.3% (65/78) of the mutant alleles ultimately found in these 87 patients. In addition, sequencing only 9 exons would detect over 50% of the identified variants and require less than 5% of the labor and cost of comprehensive sequencing for all exons., Conclusions/significance: Our results suggest that specific difference in the variation spectrum found in LCA patients from the Han Chinese and other populations are related by ethnicity. Sequencing exons in order of decreasing risk is a cost-effective way to identify causative mutations responsible for LCA, especially in the context of genetic counseling for individual patients in a clinical setting.

Recent studies have shown that mtDNA background could affect the clinical expression of Leber hereditary optic neuropathy (LHON). We analyzed the mitochondrial DNA (mtDNA) variation of 304 Chinese patients with m.11778G>A (sample #1) and of 843 suspected LHON patients who lack the three primary mutations (sample #2) to discern mtDNA haplogroup effect on disease onset. Haplogroup frequencies in the patient group was compared to frequencies in the general Han Chinese population (n = 1,689; sample #3). The overall matrilineal composition of the suspected LHON population resembles that of the general Han Chinese population, suggesting no association with mtDNA haplogroup. In contrast, analysis of these LHON patients confirms mtDNA haplogroup effect on LHON. Specifically, the LHON sample significantly differs from the general Han Chinese and suspected LHON populations by harboring an extremely lower frequency of haplogroup R9, in particular of its main sub-haplogroup F (#1 vs. #3, P-value = 1.46×10(-17), OR = 0.051, 95% CI: 0.016-0.162; #1 vs. #2, P-value = 4.44×10(-17), OR = 0.049, 95% CI: 0.015-0.154; in both cases, adjusted P-value <10(-5)) and higher frequencies of M7b (#1 vs. #3, adjusted P-value = 0.001 and #1 vs. #2, adjusted P-value = 0.004). Our result shows that mtDNA background affects LHON in Chinese patients with m.11778G>A but not suspected LHON. Haplogroup F has a protective effect against LHON, while M7b is a risk factor.

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.

Purpose: Mitochondrial DNA (mtDNA) haplogroups affect the clinical expression of Leber hereditary optic neuropathy, age-related macular degeneration, and other diseases. The objective of this study is to investigate whether an mtDNA background is associated with myopia., Methods: Blood DNA was obtained from 192 college students, including 96 individuals with moderate-to-high myopia and 96 controls without myopia. All the subjects were from a well-known isolated population living in the Chaoshan area of east Guangdong Province and speaking one of the four major dialects in southern China. The mtDNA haplogroups in the 192 subjects were determined by sequencing the mtDNA control region and partial coding regions as well as by analysis of restriction fragment length polymorphisms. Each mtDNA was classified according to the updated version of the Eastern Asian haplogroup system., Results: Sixteen mtDNA haplogroups were recognized in the 192 subjects. The overall matrilineal structures of the samples with and without myopia were similar and had genetic imprints showing their ethno-origin. There was no statistical difference in frequencies of haplogroup distribution between subjects with and without myopia (chi(2) test, p=0.556)., Conclusions: We failed to identify clues that suggest an involvement of mtDNA background in the predisposition to myopia.

Purpose: To screen ten genes for mutations in 32 Chinese patients with microphthalmia and/or coloboma., Methods: Genomic DNA was prepared from 32 unrelated patients with microphthalmia (nine probands) and uveal coloboma (23 probands). Cycle sequencing was used to detect sequence variations in ten genes, including BMP4, VSX2, CRYBA4, GDF6, OTX2, RAX, SIX3, SIX6, SOX2, and LRP6. Variations were further evaluated in 96 unrelated controls by using restriction fragment length polymorphism (RFLP) or heteroduplex-single strand conformation polymorphism (HA-SSCP) analysis., Results: In the ten genes, a novel c.751C>T (p.H251Y) in BMP4 was detected in a patient with bilateral microphthalmia and unilateral cataract. The c.751C>T variation is also present in his healthy brother (and possibly one of the normal parents). In addition, a novel c.608G>A (p.R203Q) in SIX6 was identified in an internal control for optimizing experimental conditions. The internal control was from a girl with typical aniridia and an identified c.718C>T (p.R240X) mutation in PAX6, suggesting the c.608G>A variation in SIX6 was unlikely to play a role in her ocular phenotype. The c.751C>T in BMP4 and the c.608G>A in SIX6 were not present in the 96 normal controls. In addition, 16 nucleotide substitutions, including eight known SNPs and eight new synonymous changes, were detected., Conclusions: Although the genetic etiology for microphthalmia and/or coloboma is still elusive, rare variations in the related genes, such as c.608 G>A in SIX6 and c.751C>T in BMP4, may not be causative. These results further emphasize the importance of careful clinical and genetic analysis in making mutation-disease associations.

Purpose: To study the association of the single nucleotide polymorphisms (SNPs) rs17576 and rs2250889 in the extracellular matrix metalloprotease-9 (MMP-9) gene with primary angle closure glaucoma (PACG) in southern Chinese patients., Methods: DNA samples were obtained from 211 adult patients with PACG and 205 control subjects to study the relationships between SNPs in MMP-9 and PACG. Polymorphism analyses of rs17576 and rs2250889 in MMP-9 were performed using the polymerase chain reaction,restriction fragment length polymorphism (RFLP), and direct DNA sequencing techniques. The association between genetic polymorphisms and the risk of PACG were estimated by chi2 test and logistic regression., Results: Genotyping of the MMP-9 site (rs2250889) was significantly different between the two groups (P=0.004), and the odds ratio was OR=1.76 (95%CI: 1.264-2.449). The frequencies of the G/G genotype in the PACG and control groups were 9% and 2.9%, respectively. However, there were no significant differences between these two groups in the frequencies of the genotypes and alleles for rs17576 in MMP-9., Conclusion: The SNP rs2250889 located in MMP-9 might be associated with PACG among southern Chinese people, and people with the G/G genotype are likely more susceptible to PACG. In contrast, the SNP rs17576 in MMP-9 might not be related to PACG in the same population.

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.

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.

Mitochondrial DNA background has been shown to be involved in the penetrance of Leber's hereditary optic neuropathy (LHON) in western Eurasian populations. To analyze mtDNA haplogroup distribution pattern in Han Chinese patients with LHON and G11778A mutation, we analyzed the mtDNA haplogroups of 41 probands with LHON known to harbor G11778A mutation by sequencing the mtDNA control region hypervariable segments and some coding region polymorphisms. Each mtDNA was classified according to the available East Asian haplogroup system. The haplogroup distribution pattern of LHON sample was then compared to the reported Han Chinese samples. Haplogroups M7, D, B, and A were detected in 11 (26.8%), 10 (24.4%), 8 (19.5%), and 5 (12.2%) LHON families, respectively, and accounted for 82.9% of the total samples examined. For the remaining seven mtDNAs, six belonged to M8a, M10a, C, N9a, F1a, and R11, respectively, and one could only be assigned into macro-haplogroup M. The LHON sample was distinguished from other Han Chinese samples in the principal component map based on haplogroup distribution frequency. Our results show that matrilineal genetic components of Chinese LHON patients with G11778A are diverse and differ from related Han Chinese regional samples. mtDNA background might affect the expression of LHON and the G11778A mutation in Chinese population.

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.

Six males in a Chinese family affected by congenital cataracts, cerebellar ataxia, short stature, and mental retardation, which were tentatively named CASM syndrome. Eight female carriers in the family had cataracts alone. Linkage analysis demonstrated that the disease is transmitted through X-linked inheritance, either by setting the syndrome in males as an X-linked recessive trait, or by setting cataracts in the family as an X-linked dominant trait. The gene responsible for the syndrome is mapped to Xpter-Xq13.1, with the highest lod score of 3.91 for DXS1226, DXS991, and DXS1213 at theta = 0. Haplotype analysis identified that the allele harboring the disease gene co-segregated with all female carriers as well as affected males in the family. Clinically and genetically, the disease in this family is different from any known disease. Major features of CASM syndrome that distinguish it from other diseases are X-linked inheritance and cataracts in carrier females.