[Anticipation in patients with iridescent multicoloured posterior capsular lens opacities ("Christmas tree cataract") : The Role in the diagnosis of myotonic dystrophy].

Der Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft

PubMedID: 19326122

Reiter C, Gramer E. [Anticipation in patients with iridescent multicoloured posterior capsular lens opacities ("Christmas tree cataract") : The Role in the diagnosis of myotonic dystrophy]. Ophthalmologe. 2009;106(12):1116-20.
BACKGROUND
Myotonic dystrophy (DM type 1) is the most common type of muscular dystrophy in adults, accompanied by myotonia, iridescent multicoloured posterior capsular lens opacities ("Christmas tree cataract", CTC), and, for example, cardiac arrhythmias and respiratory failure. A further feature is anticipation, which is the occurrence of increasing disease severity and decreasing age of onset in successive generations, depending on inherited unstable DNA sequences that become larger with each generation.

AIM
To evaluate the frequency of clinically manifest DM in patients with CTC and the age at diagnosis of CTC.

METHODS
Retrospective analysis of ophthalmologic, neurologic, and internal findings in 18 consecutively diagnosed patients with CTC.

RESULTS
Three of 18 CTC patients showed clinical signs of DM. The mean age at diagnosis was 72,8+/-16,5 years (range 36-94 years).

DISCUSSION
A relationship existed between CTC and manifest DM in 16.7% of the patients with CTC. A hypothesis states that the other 83.3% might have premutations in the DMPK gene, which might lead to a complete mutation after transmission through subsequent generations. In the meantime, molecular genetic DM tests are available. Because of clinical heterogeneity and the anticipation phenomenon in DM, confirmation with such molecular genetic DM tests should be obtained.