Screening of pathogenic mutation in a Chinese family with congenital pulverulent cataract / 中华实验眼科杂志

Objective To analysis the pathogenic mutation and the clinical characteristics of a three generation family with congenital pulverulent cataract. Methods A congenital cataract family was chosen from the First Affiliated Hospital of AnHui Medical University,5 ml peripheral blood was obtained from each family member to extract genomic DNA. Next generation sequencing was used to detect the mutation in proband (Ⅱ5),Ⅱ6 and Ⅲ8, and Sanger sequencing was applied to verify pathogenic mutation in the whole family members. The mutation site was compared with the gene sequence of 10000 normal Chinese. PolyPhen-2 and SIFT were applied to analysis the alteration on the protein structure and function and its possible pathogenesis. This study followed the Declaration of Helsinki and was approved by the Ethics Committee of AnHui Medical University ( NO. PJ2017-5-17 ) . All patients signed informed consent. Results The pedigree consisted of 19 members of three generations,including 10 patients and 9 normal family members. Heterozygous mutation of GJA3 gene c. 427G>A ( p. G143R) was detected in all patients of the pedigree,but was not found in normal members of the pedigree and 10000 normal Chinese. The score calculated from SIFT and PolyPhen-2 indicated that the mutation probably had malignant effect on normal protein structure,Swiss-model website analysis showed that the mutation likely altered the secondary structure of the protein CX 46 by reducing anα-helix between 107-115 amino acids. Meanwhile,c. 1325-1G>T mutation of HSF4 gene were detected in Ⅱ5 and Ⅲ8, which was not found in other family members and 10000 normal Chinese. HSF and MaxEntScan results showed that the mutation probably had serious effect on the splicing of mRNA. The cataract development rates of Ⅱ5 andⅢ8 were faster than that of the same age in the same generation of the pedigree,and the morphology of lens opacity was changed. Conclusions The heterozygous c. 427G>A mutation in GJA3 gene is responsible for pulverulent cataract in this family,meanwhile the c. 1325-1G>T mutation in HSF4 gene may change the type of phacoscotasmus and accelerate the progress of disease.

Screening of pathogenic mutation in a Chinese family with congenital pulverulent cataract / 中华实验眼科杂志

Objective@#To analysis the pathogenic mutation and the clinical characteristics of a three generation family with congenital pulverulent cataract.@*Methods@#A congenital cataract family was chosen from the First Affiliated Hospital of AnHui Medical University, 5 ml peripheral blood was obtained from each family member to extract genomic DNA.Next generation sequencing was used to detect the mutation in proband (Ⅱ5), Ⅱ6 and Ⅲ8, and Sanger sequencing was applied to verify pathogenic mutation in the whole family members.The mutation site was compared with the gene sequence of 10 000 normal Chinese.PolyPhen-2 and SIFT were applied to analysis the alteration on the protein structure and function and its possible pathogenesis.This study followed the Declaration of Helsinki and was approved by the Ethics Committee of AnHui Medical University (NO.PJ2017-5-17). All patients signed informed consent.@*Results@#The pedigree consisted of 19 members of three generations, including 10 patients and 9 normal family members.Heterozygous mutation of GJA3 gene c. 427G>A (p.G143R) was detected in all patients of the pedigree, but was not found in normal members of the pedigree and 10 000 normal Chinese.The score calculated from SIFT and PolyPhen-2 indicated that the mutation probably had malignant effect on normal protein structure, Swiss-model website analysis showed that the mutation likely altered the secondary structure of the protein CX 46 by reducing an α-helix between 107-115 amino acids.Meanwhile, c.1325-1G>T mutation of HSF4 gene were detected in Ⅱ5 and Ⅲ8, which was not found in other family members and 10 000 normal Chinese.HSF and MaxEntScan results showed that the mutation probably had serious effect on the splicing of mRNA.The cataract development rates of Ⅱ5 and Ⅲ8 were faster than that of the same age in the same generation of the pedigree, and the morphology of lens opacity was changed.@*Conclusions@#The heterozygous c. 427G>A mutation in GJA3 gene is responsible for pulverulent cataract in this family, meanwhile the c. 1325-1G>T mutation in HSF4 gene may change the type of phacoscotasmus and accelerate the progress of disease.

Identification of a GJA3 mutation in a Chinese family with congenital nuclear cataract using exome sequencing.

Congenital cataract, a clinically and genetically heterogeneous lens disorder is defined as any opacity of the lens presented from birth and is responsible for approximately 10% of worldwide childhood poor vision or blindness. To identify the genetic defect responsible for congenital nuclear cataract in a four-generation Chinese Han family, exome and direct Sanger sequencings were conducted and a missense variant c.139G>A (p.D47N) in the gap junction protein-alpha 3 gene (GJA3) was identified. The variant co-segregated with patients of the family and was not observed in unaffected family members or normal controls. The above findings indicated that the variant was a pathogenic mutation. The mutation p.D47N was found in the first extracellular loop (E1) domain of GJA3 protein. Our data suggest that exome sequencing is a powerful tool to discover mutation(s) in cataract, a disorder with high genetic heterogeneity. Our findings may also provide new insights into the cause and diagnosis of congenital nuclear cataract and have implications for genetic counseling.