Genetic factors have been suggested to contribute to the etiology of moyamo
ya disease. The authors have previously reported an association between moy
amoya disease and several alleles for human leukocyte antigens (HLA). To fu
rther specify the genetic component of moyamoya disease, a linkage study of
moyamoya disease using markers on chromosome 6, where the HLA gene is loca
ted, was performed. The 15 microsatellite markers of chromosome 6 were stud
ied in 20 affected sibling pairs. From an identical-by-descent analysis of
these markers, an allele with possible linkage to moyamoya disease was iden
tified. Sharing of the allele among affected members in 19 families was inv
estigated, considering the haplotype. The marker, D6S441, might be linked t
o moyamoya disease. Considering the haplotype, the allele was shared among
the affected members in 16 (82%) of the 19 families, but not in two others.
In one family, sharing of the allele could not be determined because of lo
w heterozygosity. Further studies are necessary to clarify multiple genetic
factors that are definitely linked with moyamoya disease.