The use of apolipoprotein CII as a genetic marker for myotonic dystrophy.

In five families we have confirmed the close linkage between the genes for myotonic dystrophy and apolipoprotein CII. The total maximum lod (log of the odds) score was 3.32 at 0 recombination. We demonstrate that the use of a Ban I restriction site polymorphism for apolipoprotein CII adds additional useful information when combined with the more commonly used Taq I polymorphism. The potential practical clinical use of these markers for the prenatal diagnosis of myotonic dystrophy is demonstrated.