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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.)

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.

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: To identify null mutations in novel genes associated with early-onset high myopia using whole exome sequencing., Methods: Null mutations, including homozygous and compound heterozygous truncations, were selected from whole exome sequencing data for 298 probands with early-onset high myopia. These data were compared with those of 507 probands with other forms of eye diseases. Null mutations specific to early-onset high myopia were considered potential candidates. Candidate mutations were confirmed with Sanger sequencing and were subsequently evaluated in available family members and 480 healthy controls., Results: A homozygous frameshift mutation (c.39dup; p.L14Afs*21) and a compound heterozygous frameshift mutation (c.39dup; p.L14Afs*21 and c.594delG; p.Q199Kfs*35) in LOXL3 were separately identified in two of the 298 probands with early-onset high myopia. These mutations were confirmed with Sanger sequencing and were not detected in 1,974 alleles of the controls from the same region (507 individuals with other conditions and 480 healthy control individuals). These two probands were singleton cases, and their parents had only heterozygous mutations. A homozygous missense mutation in LOXL3 was recently reported in a consanguineous family with Stickler syndrome., Conclusions: Our results suggest that null mutations in LOXL3 are likely associated with autosomal recessive early-onset high myopia. LOXL3 is a potential candidate gene for high myopia, but this possibility should be confirmed in additional studies. LOXL3 null mutations in human beings are not lethal, providing a phenotype contrary to that in mice.

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: 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.

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: Two previous genome-wide association studies (GWAS) of high myopia in a Japanese population found several single nucleotide polymorphisms (SNPs) associated with the disease. The present study examined whether these markers are associated with myopia in a Chinese population., Methods: Individuals with or without complex myopia were recruited from Chinese university students, and probands with early onset high myopia were identified in the Pediatric and Genetic Eye Clinic of the Zhongshan Ophthalmic Center. DNA was prepared from venous leukocytes. Three SNPs, rs577948 and rs11218544 at chromosome position 11q24.1 and rs2839471 at chromosome position 21q22.3, were genotyped. The allele and genotype frequencies of these SNPs were compared between the myopia cases and controls using a χ(2) test., Results: A total of 2,870 subjects were examined in this study, including 1,255 individuals with complex myopia (-10.00 diopter (D)

Purpose: To identify the genetic locus and mutation responsible for autosomal dominant cone dystrophy (adCOD) in a large Chinese family and to describe the phenotypes of the patients., Methods: Genomic DNA and clinical data were collected from the family. Genome-wide linkage analysis was performed to map the disease locus, and Sanger dideoxy sequencing was used to detect the mutation in a candidate gene., Results: Initially, genome-wide linkage analysis mapped the disease to 17p13.1 between D17S831 and D17S799, with a maximum lod score of 2.71 for D17S938 and D17S1852 at theta=0. Sequence analysis of the guanylate cyclase 2D gene (GUCY2D) in the linkage interval detected a recurrent heterozygous mutation, c.2513G>A (p.Arg838His). This mutation was present in all eight patients with adCOD, but neither in any of the six unaffected family members nor in 192 control chromosomes., Conclusions: adCOD in this family is caused by a recurrent mutation in GUCY2D. adCOD can be detected in the first few years after birth in the family by fundus observation and electroretinogram recordings.

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.

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: 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_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.

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: 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.

Purpose: Myopia is the most common visual problem in the world. High myopia, the extreme form of myopia that can be complicated by retinal detachment and macular degeneration, affects 1%-2% of the general population. The genes responsible for nonsyndromic high myopia have not been identified although several chromosome loci have been suggested. Additional loci for the majority of high myopia, especially in Asian populations, await discovery. A large Chinese family with autosomal dominant high myopia was collected in order to map the genetic locus as an initial step towards identifying the genetic cause of high myopia in this family., Methods: A Chinese family with 12 individuals affected with high myopia was ascertained from a small village in central China. Phenotypic information and DNA samples were collected from 18 individuals, including 11 affected and 7 unaffected individuals. A genome-wide scan was performed using markers spaced at about 10 cM intervals for genotyping and two-point linkage analysis was carried out. Candidate genes were sequenced., Results: High myopia, ranging from -5.00 D to -20.00 D with typical fundus changes, is transmitted as an autosomal dominant trait in this family. High myopia in this family shows linkage to markers in a 20.4 cM region between D4S1578 and D4S1612, with maximum lod scores of 3.11 and 3.61 at theta=0 by D4S1564 and by the D4S2986-D4S1572-D4S1564-D4S406-D4S1580-D4S402 haplotype, respectively. Sequence analysis of the retinal pigment epithelium-derived rhodopsin homolog (RRH; OMIM 605224) gene inside the linked region did not identify any causative mutations., Conclusions: A novel locus (MYP11) for autosomal dominant high myopia in a Chinese family maps to 4q22-q27 but is not associated with mutations in RRH.

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_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.