Identification of the p. R116H mutation in a Chinese family with novel variable cataract phenotype: evidence for a mutational hot spot in αA-crystallin gene

Detection of TORCH pathogens in children with congenital cataracts

The aim of the present study was to investigate the correlation between infection rates with TORCH pathogens including toxoplasma, rubella virus, cytomegalovirus, and herpes simplex virus (HSV) I and II and congenital cataracts. In total, the data from 69 children with congenital cataract treated at the Children's Hospital of the Zhejiang University School of Medicine between May 2006 and September 2013 were examined, including the complete serum test results for immunoglobulin (Ig)G and IgM that target TORCH pathogenic antibodies. These results were compared with the antibody levels of 5,914 children in a control group. Using SPSS 19.0 software, variance equation Levene tests, mean equation t tests, and completely randomized design of four tables χ² tests were applied. The HSV II IgG positivity rates significantly differed between the cataract and control groups. These results suggested that HSV may be one of the pathogenic viruses that leads to congenital cataracts.

Recurrent mutation in the crystallin alpha A gene associated with inherited paediatric cataract

Background

Cataract is a major cause of childhood blindness worldwide. The purpose of this study was to determine the genetic cause of paediatric cataract in a South Australian family with a bilateral lamellar paediatric cataract displaying variable phenotypes.

Case presentation

Fifty-one genes implicated in congenital cataract in human or mouse were sequenced in an affected individual from an Australian (Caucasian) family using a custom Ampliseq library on the Ion Torrent Personal Genome Machine. Reads were mapped against the human genome (hg19) and variants called with the Torrent Suite software. Variants were annotated to dbSNP 137 using Ion Reporter (IR 1.6.2) and were prioritised for validation if they were novel or rare and were predicted to be protein changing. We identified a previously reported oligomerization disrupting mutation, c.62G > A (p.R21Q), in the Crystallin alpha A (CRYAA) gene segregating in this three generation family. No other novel or rare coding mutations were detected in the known cataract genes sequenced. Microsatellite markers were used to compare the haplotypes between the family reported here and a previously published family with the same segregating mutation. Haplotype analysis indicated a potential common ancestry between the two South Australian families with this mutation. The work strengthens the genotype-phenotype correlations between this functional mutation in the crystallin alpha A (CRYAA) gene and paediatric cataract.

Conclusion

The p.R21Q mutation is the most likely cause of paediatric cataract in this family. The recurrence of this mutation in paediatric cataract families is likely due to a familial relationship.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-016-1890-0) contains supplementary material, which is available to authorized users.

A R54L mutation of CRYAA associated with autosomal dominant nuclear cataracts in a Chinese family

PURPOSE

To identify the genetic defect in a three-generation Chinese family with congenital cataracts.

METHODS

The phenotype of a three-generation Chinese family with congenital cataract was recruited. Detailed family history and clinical data of the family were recorded. Candidate genes sequencing was performed to screen out the disease-causing mutation. Bioinformatics analysis was performed to predict the function of mutant gene.

RESULTS

The phenotype of the family was identified as nuclear cataract. Direct sequencing revealed a c.161 G > T transversion in exon 1 of crystallin alpha-A (CRYAA). This mutation co-segregated with all affected individuals in the family and was not found in unaffected family members nor in the 100 unrelated controls. Bioinformatics analysis indicated that the 54th amino acid position was highly conserved and the mutation R54L caused an increase of local hydrophobicity around the substitution site.

CONCLUSIONS

This study identified a novel disease-causing mutation c.161 G > T (p.R54L) in CRYAA in a Chinese family with autosomal dominant nuclear cataracts, this is the first report relating a G > T mutation in CRYAA leading to congenital nuclear cataract.