Screening Of The XLRS1 Gene Mutation Of X-linked Congenital Retinoschisis

Objective:To identify the XLRS1 gene mutations and analyze genotype in three clinically diagnosed retinoschisis families (including 4 patients), supply consultation for the families.Methods:Comprehensive eye examinations on retinoschisis patients including biomicroscopy, best-corrected visual acuity(BCVA) examination, fundus examination, color fundus photography, optical coherence tomography(OCT), and fluorescence fundus angiography(FFA), electroretinogram (ERG) examination. Members of the family received best corrected visual acuity, slit lamp microscopy, fundus examination, OCT, FFA, ERG and other tests needed. Blood samples from 4 patients and family members were collected. Genomic DNA was isolated from the blood samples using standard protocols. Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method was used for detect mutations in the XLRS1 gene and adjacent intron sequence. PCR-DNA sequence was performed to identify the mutation compared with XLRS1 reference sequences(MIM:312700).Results:Four male patients(from 8 years old to 16 years old, average 10.75 years) from three families were diagnosised retinoschisis clinically, consistent with X linked heredity characteristics. Their mean visual acuity was 0.22. OCT show retinal cystoid changes. ERG show decreased b wave, a wave slightly decreased or normal. Two types of mutations,missense mutation and frame shift were identified in the three families.Missense mutation:c.625C>T (p.R209C) in Family 1 and c.002T> C (p.M1T) in Family 3. Base loss of the first exon was detected in Family 2. There were 3 carriers in Family 1 and 5 carriers in Family 3.Conclusions:1. Patients participating in this experiment are have XLRS1 gene mutation or deletion.2. Eight carriers in the three families existent are very significance for genetic counseling.