Discordant clinical outcome in myotonic dystrophy relatives showing (CTG)n > 700 repeats.

A myotonic dystrophy (DM) family is described in which discordant DM phenotypes were found in the children of two affected sisters with similar CTG expansion and clinical manifestations.
In this family, congenital as well as early severe childhood and later childhood onset DM coexist.
This observation strengthens the limited ability of lymphocytes CTG repeat number analysis in predicting genotype-phenotype correlations in DM patients.. 
