RESUMEN
The gene for human apolipoprotein CII (APOCII) is located on the proximal long arm of chromosome 19. It has been established as a closely linked marker for myotonic dystrophy (DM), the most common form of adult muscular dystrophy. In the present linkage study, we have analysed 6 APOCII RFLPs in 213 haplotypes: TaqI, 3.8/3.5 kb; BgII, 12.0/9.0 kb; BanI, 2.5/1.6 kb; BamHI, 6.0/4.9 kb; NcoI, 14.5/11.5 kb, and AvaII, 0.6/0.4 kb. The polymorphic enzyme sites were determined to be present at the following frequencies: TaqI, 0.43; BglI, 0.51; BanI, 0.25; BamHI, 0.99; NcoI, 0.51, and AvaII, 0.52. Ordering of the polymorphic sites, 5'----3', has been determined to be (NcoI-BglI)-AvaII-BanI-TaqI. Significant disequilibrium was seen between 5 of the APOCII RFLPs.