Only three cases of congenital myotonic dystrophy type 2 (DM2) have been reported so far. In all cases, the disease was transmitted from the mother and the children had bilateral club feet or unilateral club feet.
- A Dutch team reports a case of an 8-year-old girl with DM2 who was born with a valgus flat foot with unilateral equinus.
- Her mother and grandmother were diagnosed with DM2 with proximal muscle weakness, pain and myotonia at the age of 32 and 62 years respectively.
- There was no family history of foot deformity.
- The size of the CCTG expansion in all affected family members ranged from 250 to over 2000 repetitions.
The phenomenon of clinical anticipation of DM2 does not appear to be correlated with an increase in expansion size. It would be associated with maternal transmission of the disease.
