151. Novel mutations in the XLRS1 gene may be caused by early Okazaki fragment sequence replacement.
- Author
-
Rodriguez IR, Mazuruk K, Jaworski C, Iwata F, Moreira EF, and Kaiser-Kupfer MI
- Subjects
- Adult, Base Sequence, Child, DNA Mutational Analysis, Electrophoresis, Polyacrylamide Gel, Exons, Female, Genetic Linkage, Humans, Infant, Newborn, Male, Molecular Sequence Data, Pedigree, Polymerase Chain Reaction, Polymorphism, Single-Stranded Conformational, X Chromosome genetics, DNA analysis, Eye Proteins genetics, Mutation, Retinal Diseases genetics, Sequence Deletion
- Abstract
Purpose: To determine whether two families diagnosed with X-linked retinoschisis contained mutations in the XLRS1 gene., Methods: DNA from the patients was obtained from blood lymphocytes using commercially available kits. Single-strand conformation assay was performed in an electrophoresis apparatus using 10% acrylamide TBE gels at 10 degrees C. The gels were stained with SYB green II and were scanned in a phosphoimager. DNA was sequenced using an automated fluorescence sequencer., Results: A deletion that eliminates exon 2 was found in one family. An abnormal sequence replacement in exon 4 was found in the other family. Both mutations have severe effects in the coding region by inserting premature stop codons., Conclusions: Both of the families have mutations in the XLRS1 gene. One of these mutations points to a novel mechanism. The mutation is caused by a replacement of 17 bp of a normal sequence with 20 bp of a sequence originating from two different places in the antisense strand. This suggests that early Okazaki fragments were incorporated into the sense strand of exon 4, replacing the normal sequence.
- Published
- 1998