Abstract
To identify the genetic defect associated with autosomal dominant congenital nuclear cataract in a Chinese family, molecular genetic investigation via haplotype analysis and direct sequencing were performed Sequencing of the CRYGD gene revealed a c.127T>C transition, which resulted in a substitution of a highly conserved tryptophan with arginine at codon 43 (p.Trp43Arg). This mutation co-segregated with all affected individuals and was not observed in either unaffected family members or in 200 normal unrelated individuals. Biophysical studies indicated that the p.Trp43Arg mutation resulted in significant tertiary structural changes. The mutant protein was much less stable than the wild-type protein, and was more prone to aggregate when subjected to environmental stresses such as heat and UV irradiation. © 2010 Wiley-Liss, Inc.
Highlights
Cataract, characterized by opacification of all or part of the eye’s crystalline lens (Reddy, et al, 2004) and one Received 7 May 2010; accepted revised manuscript 29 August 2010.E1940 Binbin Wang et al.of the most common treatable cause of visual loss in humans, can be generally categorized as early onset and age-related (Vijaya, et al, 1997)
Affected status was determined by a history of cataract extraction or ophthalmologic examination, and the affected individuals all presented with bilateral congenital nuclear cataracts, which consisted of a central nuclear opacity affecting the embryonic and fetal nucleus of the lens, while the cortex remained transparent (Figure 1b, the proband)
Eight genes for nuclear cataract have been identified (CRYBA1, CRYAA, and CRYGD, which are related with the nuclear phenotype but not the pulverulent, and CX46, CX50, CRYBB2, CRYBB3 and CRYGC, which are candidates for nuclear pulverulent only)
Summary
Cataract, characterized by opacification of all or part of the eye’s crystalline lens (Reddy, et al, 2004) and one Received 7 May 2010; accepted revised manuscript 29 August 2010.E1940 Binbin Wang et al.of the most common treatable cause of visual loss in humans, can be generally categorized as early onset (congenital or juvenile) and age-related (Vijaya, et al, 1997). Cataract, characterized by opacification of all or part of the eye’s crystalline lens (Reddy, et al, 2004) and one Received 7 May 2010; accepted revised manuscript 29 August 2010. There are over eleven crystallin genes, encoding over 95% of the water-soluble structural proteins present in the crystalline lens and representing over 30% of its mass. The crystallin family can be divided into three distinct groups, including α-crystallins (CRYAA and CRYAB), β- and γ-crystallins (CRYBA1/A3/A4/B1/B2/B3 and CRYGA/B/C/D/S), which are included in a superfamily of microbial stress proteins and share a common twodomain structure, composed of four “Greek-key” motifs. The unique spatial arrangement and solubility of crystallins are essential to the optical transparency and high refractive index of the lens. Modification of crystallins can disrupt their normal structure in the lens and cause cataracts (van Rens, et al.., 1991)
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