Huntington Disease in Finland: Linkage Disequilibrium of Chromosome
4 RFLP Haplotypes and Exclusion of a Tight Linkage Between the
Disease and D4S43 Locus
E. Ikonen, J. Palo, J. Ott, J. Gusella,
H. Somer, L. Karila, A. Palotie, L. Peltonen
American Journal of Human Genetics , 46(1), 5--11 (1990 Jan)
Abstract
The question about heterogeneity of Huntington disease (HD) at the
DNA level can be approached by analyzing the RFLP haplotypes formed
by several RFLP loci of the diseased chromosome in different
populations. In genetically isolated populations such as Finland, it
is further possible to use this approach to test the hypothesis of a
single mutation enriched in this population demonstrating an
exceptionally low prevalence of HD. In this study covering 70% of
all diagnosed HD cases in Finland, linkage disequilibrium of RFLP
haplotypes of D4S10 and D4S43 loci polymorphisms was found. This
phenomenon, not so far reported in any other population, could
support the hypothesis of one ancestor HD mutation in the Finnish
population. Despite the lower heterozygosity obtained with some RFLP
markers, the proportion of individuals receiving informative DNA
test results did not significantly differ from that reported in more
mixed populations. In one HD family we established a recombination
event between HD and the D4S43 locus, an event which can be highly
useful in the more precise mapping of the HD gene.
