Genetic variations in the hotspot region of RS1 gene in Indian patients with juvenile X-linked retinoschisis.
OBJECTIVE
X-linked juvenile retinoschisis (XLRS) is the leading cause of macular degeneration in males. This condition is caused by mutations in the RS1 gene and is, characterized by schisis within the retina. The purpose of this study was to identify the mutations in the RS1 gene associated with XLRS in an Indian cohort.


METHODS
The coding region of RS1 was analyzed for mutations by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) and restriction fragment length polymorphism (RFLP) analysis in six unrelated subjects clinically diagnosed as having XLRS and in their available family members. Direct sequencing was performed for all samples that displayed an electrophoretic mobility shift in SSCP gel.


RESULTS
Mutation analysis of RS1 gene revealed five mutations in exon 6 like c.574C>T, c.583A>G, c.608C>T, c.617G>A, and c.637C>T, respectively, among them four missense mutations, one nonsense mutation, and two novel sequence variations. These mutations were found in individuals who exhibited clinical features of bilateral foveal and peripheral retinoschisis consistent with XLRS. The mutations were absent in the 100 age matched control samples analyzed.


CONCLUSIONS
This is the first report of mutations in RS1 to be associated with XLRS in the Indian population. The identified genetic variations, phenotype and genotype correlations were consistent with other studies. Identification of the causative mutation in patients with XLRS is helpful in confirming the diagnosis and in counseling of family members.
Suganthalakshmi
Balasubbu
B
Department of Genetics, Aravind Medical Research Foundation, Madurai, India.
Shukla
Dhananjay
D
Rajendran
Anand
A
Kim
Ramasamy
R
Nallathambi
Jeyabalan
J
Sundaresan
Periasamy
P
D000293:Adolescent; D000328:Adult; D044466:Asian People / Q000235:genetics*; D002648:Child; D018389:Codon, Nonsense; D004252:DNA Mutational Analysis; D004591:Electrophoresis, Polyacrylamide Gel; D005091:Exons; D005136:Eye Proteins / Q000235:genetics*; D014644:Genetic Variation; D006801:Humans; D007194:India; D008297:Male; D020125:Mutation, Missense; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D018807:Polymorphism, Single-Stranded Conformational; D017434:Protein Structure, Tertiary; D041441:Retinoschisis / Q000235:genetics*
D018389:Codon, Nonsense; D005136:Eye Proteins; C108726:RS1 protein, human