BACKGROUND AND PURPOSE: Moyamoya disease is a cerebrovascular disease of unknown 
cause that mainly affects Japanese children. The incidence of familial 
occurrence accounts for 9% of cases. The characteristic lesions of moyamoya 
disease are occasionally seen in neurofibromatosis type 1, of which the 
causative gene (NF1) has been assigned to chromosome 17q11.2.
METHODS: To determine whether a gene related to moyamoya disease is located on 
chromosome 17, we conducted microsatellite linkage analyses on 24 families 
containing 56 patients with moyamoya disease. Leukocyte DNA extracted from the 
family members was subjected to polymerase chain reaction for a total of 22 
microsatellite markers on chromosome 17. The amplified polymerase chain reaction 
fragments were analyzed with GeneScan on an automated sequencer.
RESULTS: Two-point linkage analysis gave a maximum log(10) odds (LOD) score of 
3.11 at the recombination fraction of 0.00 for the marker at locus D17S939. The 
affected pedigree member method also showed a significantly low P value (<1. 
0x10(-5)) for the 5 adjacent markers at 17q25. Multipoint linkage analysis also 
indicated that the disease gene is contained within the 9-cM region of D17S785 
to D17S836, with a maximum LOD score of 4. 58.
CONCLUSIONS: A gene for familial moyamoya disease is located on chromosome 
17q25.