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Mol Vis. 2007 Jul 13;13:1154-60.

Two Chinese families with pulverulent congenital cataracts and deltaG91 CRYBA1 mutations.

Author information

1
Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital-Solna, Stockholm, Sweden.

Abstract

PURPOSE:

To characterize the disease-causing mutations and related phenotypes in two Chinese families with autosomal dominant congenital cataract.

METHODS:

Family members were clinically characterized by a complete eye examination. Genome-wide linkage screening was performed in Family 1 using a 10K single nucleotide polymorphism approach followed by genotyping of microsatellite markers from the regions with highest support for linkage. The candidate gene, betaA1-crystallin (CRYBA1), was sequenced in both families.

RESULTS:

Lens examinations in three affected phakic members showed bilateral pulverulent nuclear cataracts in two subjects of Family 1 while another subject of Family 2 displayed bilateral pulverulent lamellar cataract. Linkage analysis in 14 individuals (eight affected, three unaffected and three of their spouses) of Family 1 gave a maximum logarithm of odds score of 2.41 for D17S1294 in chromosomal region 17q11.12 that includes the CRYBA1 gene. In both families in-frame deletions of three bp were detected in exon 4 of CRYBA1 leading to loss of a guanine residue (deltaG91). The mutations cosegregated completely with the cataract phenotype in both families but were associated with distinct haplotypes suggesting that they had occurred independently.

CONCLUSIONS:

The previously described CRYBA1 mutation deltaG91 was demonstrated in two Chinese families with distinct phenotypes of congenital cataract, suggesting a lack of genotype-phenotype correlation. The findings also raise the possibility that the delta91 mutation arise in a relatively mutation-prone sequence of the CRYBA1 gene.

PMID:
17653060
[Indexed for MEDLINE]

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