The Change of Grip Strength in a Patient with Congenital Myotonic Dystrophy Over a 4-year Period.

Myotonic dystrophy(MyD) is a neuromuscular diseasethat is autosomal dominant and the most common form of muscular dystrophy affecting adults. The clinical features of MyD include a multisystemic disorder characterized by myotonia, progressive muscle weaknessand wasting, cataracts, premature balding and mental retardation. The most severe type of MyD is classified as congenital MyD (CMyD). The muscle weaknessin CMyD is very severe, but muscle development can be observed in the period of growth. However, no clinical case of this type has been reported yet. Therefore, we report on a girl with CMyD who had an increase in muscle strength over a four-year period. The girl with CMyD participated in this study from the age of 9 to the age of 12. The measurement of muscle strength was recorded as the maximum score of grip strengthwith the use of dynamometers. Grip strengthwas assessed once a year by the same two physical therapists. Grip strengthof CMyD for each year was markedly weak when compared with the normal controls, but muscle strength changed within some specific growth areas. The muscle weaknessin CMyD was remarkable, but the result showed that specific muscle strength of CMyD in childhood was actually increased.