Myotonic dystrophy type 1 in cataract patients: Molecular diagnosis for screening and genetic counseling

Abstract

Purpose: To detect MD1 premutation and full mutation carriers among cataract patients and offer familial genetic counseling. Methods: We studied the DNA of 60 selected cataract patients through polymerase chain reaction analysis. This study was performed at the "Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto" where selected patients had been examined at the Cataract Outpatient Clinic from 01/01/1982 to 30/06/1995. Selection criteria were age under 55 with no obvious precipitating factor, except diabetes mellitus type 2, with or without neuromuscular signs suggestive of myotonic dystrophy. Results: Three patients were found to have a full mutation corresponding to 5% of the group. Additional affected individuals were found among patients' relatives. No premutation was found. Conclusions: These results emphazise the importance of screening for MD1 gene carriers among cataract patients, and further genetic counselling.