A chromosome 19 clone from a translocation breakpoint shows close linkage and linkage disequilibrium with myotonic dystrophy.
The gene for myotonic dystrophy (DM), the most common form of adult muscular dystrophy, is situated on the proximal long arm of chromosome 19. Although there exist markers that are tightly linked to the DM locus, its precise location is unknown. The identification and characterization of additional DNA probes closely linked to the DM locus continue to be priorities. In this study, we report on the linkage between a new DNA marker, designated p alpha 1.4P, and the DM locus in 50 families. The probe p alpha 1.4P was derived from a cloned breakpoint junction fragment from the chromosomal translocation t(14;19)(q32;q13.1). This translocation has been previously described in some cases of chronic lymphocytic leukemia. We have identified a BanI restriction fragment length polymorphism that is detected by p alpha 1.4P. Segregation analysis between this RFLP and DM revealed close linkage between the two loci (lod = 10.95, theta = 0). Furthermore, statistical evidence for linkage disequilibrium between p alpha 1.4P and the DM locus in a French Canadian population was found. Finally, by means of a somatic cell hybrid mapping panel, p alpha 1.4P was sublocalized to 19q12----19q13.2.
Korneluk
R G
RG
Division of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Canada.
MacLeod
H L
HL
McKeithan
T W
TW
Brooks
J D
JD
MacKenzie
A E
AE
D000483:Alleles; D002874:Chromosome Mapping; D002888:Chromosomes, Human, Pair 19; D015252:Deoxyribonucleases, Type II Site-Specific; D008040:Genetic Linkage; D005819:Genetic Markers; D006801:Humans; D009136:Muscular Dystrophies / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D014178:Translocation, Genetic
D005819:Genetic Markers; C051612:endodeoxyribonuclease BanI; D015252:Deoxyribonucleases, Type II Site-Specific