X-linked juvenile retinoschisis associated with a 4-base pair insertion atcodon 55 of the XLRS1 gene

X-linked juvenile retinoschisis (RS) is a bilateral vitreoretinal disorder with no known cure. The gene responsible for the disease was recently isola ted by positional cloning methods and a spectrum of mutations has been desc ribed in families with RS pathology. In this report, we screened six sporad ic cases of RS for mutations in the RS gene to understand the etiology of i solated cases. Our extensive studies revealed a novel 4 bp insertion in one family and the remaining families did not show mutations in the RS gene. T his mutation altered the reading frame including codon 55 resulting in nine aberrant amino acid residues. The unaffected mother did not contain this m utation. Additionally, it was not found in 60 normal control chromosomes, s uggesting that the insertion mutation is disease related in the family anal yzed. (C) 2000 Academic Press.