How Does Myotonic Dystrophy Type 2 Differ From Type 1

How does Myotonic dystrophy type 2 differ from type 1

In DM2, muscle weakness is usually proximal and facial weakness is minimal. Myotonia is usually absent on examination but is present on EMG testing.

There is no congenital form. Systemic involvement closely resembles DM1.

The mutation is due to a CCTG expansion in a specific zinc-finger gene ( ZNF9 ) localized to chromosome 3q.

Anticipation is less marked when compared to DM1. DM2 should be considered in any atypical progressive disorder with proximal muscle weakness.