Primary cataract as a key to recognition of myotonic dystrophy type 1

Abstract

Purpose: Primary cataract is often the initial manifestation of the adult-onset type of myotonic dystrophy type 1 (DM1), the most common muscular dystrophy in adults. It is caused by a CTG repeat expansion within the DMPK gene, and anticipation may cause earlier onset and more severe symptoms in subsequent generations.

Methods: We report a family with hereditary cataract, which was initially classified as primary hereditary cataract. After presentation of 2 children with motor development delay and behavioral changes, DM1 was diagnosed. Subsequently, various DM1 features were recognized in older family members.

Conclusions: This report aims to increase awareness among ophthalmologists of the high prevalence of DM1 among young primary cataract patients. Ophthalmologists can play a significant role in early diagnosis, since cataract frequently is the first occasion that patients seek medical attention. Early recognition is crucial since it enables adequate cardiac follow-up and allows counseling of couples of childbearing age.