Myotonic dystrophy is closely linked to the gene for muscle-type creatine kinase (CKMM).

We have studied genetic linkage between the gene for creatine kinase muscle type (CKMM) and the gene for myotonic dystrophy (DM). In a panel of 65 myotonic dystrophy families from Canada and the Netherlands, a maximum lod score (Zmax) of 22. 8 at a recombination frequency (theta) of 0. 03 was obtained.
Tight linkage was also demonstrated for CKMM and the gene for apolipoprotein C2 (ApoC2). This establishes CKMM as a useful marker for myotonic dystrophy 
