Abstract
Purpose:
X-linked retinoschisis (XLRS) is a retinal dystrophy caused by mutations in the RS1gene in Xp22.1, which leads to schisis (splitting) of the neural retina leading to reduced visual acuity in affected men (OMIM #312700). The aim of this study was to identify the RS1 gene mutations in a small cohort of Chinese patients with X-linked retinoschisis, and to describe the associated phenotypes.
Methods:
Detailed ophthalmic examinations were given to the patients and unaffected individuals from the nine unrelated families. After informed consent was obtained, genomic DNA was extracted from the venous blood of all participants. All exons including the splicing region of the RS1 gene was amplified by polymerase chain reaction (PCR). The PCR products were analyzed using direct sequencing. Long-range PCR followed by DNA sequencing was used to define the breakpoints of the large deletion.
Results:
By clinical examination, ten male individuals from nine families were diagnosed of retinoschisis. The median age at review was 12.4 years (range from 5-34 years); the median best-corrected visual acuity upon review was 0.22 (range 0.02-0.5). Typical foveal schisis was found in 83.3% eyes examined (15/18) while peripheralschisis was present in 33.3% of eyes (6/18). Six novel mutations including: two nonsense c.370C>T(p.Q124X) and c.98G>A(p.W33X), one missense c.581T>A(p.I194N), one small deletionc.330delT (p.C110fs) , and one splicing mutation c.113G>T, and one large deletion, and three recurrent missens mutations were identified.
Conclusions:
The mutations found in our study broaden the spectrum of RS1 mutations. The identification of each pedigree’s specific mutation allows future determination of female carrier status for genetic consulting purposes.
Keywords: 604 mutations •
696 retinal degenerations: hereditary