Detection of linkage disequilibrium between the myotonic dystrophy locus and a new polymorphic DNA marker.
We have examined the linkage of two new polymorphic DNA markers (D19S62 and D19S63) and a previously unreported polymorphism with an existing DNA marker (ERCC1) to the myotonic dystrophy (DM) locus. In addition, we have used pulsed-field gel electrophoresis to obtain a fine-structure map of this region. The detection of linkage disequilibrium between DM and one of these markers (D19S63) is the first demonstration of this phenomenon in a heterogeneous DM population. The results suggest that at least 58% of DM patients in the British population, as well as those in a French-Canadian subpopulation, are descended from the same ancestral DM mutation. We discuss the implications of this finding in terms of strategies for cloning the DM gene, for a possible role in modification of risk for prenatal and presymptomatic testing, and we speculate on the origin and number of existing mutations which may result in a DM phenotype.
Harley
H G
HG
Institute of Medical Genetics, University of Wales College of Medicine, Cardiff, United Kingdom.
Brook
J D
JD
Floyd
J
J
Rundle
S A
SA
Crow
S
S
Walsh
K V
KV
Thibault
M C
MC
Harper
P S
PS
Shaw
D J
DJ
D002888:Chromosomes, Human, Pair 19; D005819:Genetic Markers; D005838:Genotype; D006801:Humans; D015810:Linkage Disequilibrium / Q000235:genetics*; D009223:Myotonic Dystrophy / Q000235:genetics*; D011110:Polymorphism, Genetic; D012984:Software
D005819:Genetic Markers