Deletion of Huntington's disease-linked G8 (D4S10) locus in Wolf-Hirschhorn syndrome.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized by progressive involuntary movements and dementia. The symptoms of the disease, although devastating in severity, do not usually appear until the third to fourth decade of life. The gene defect is highly penetrant, and results in the loss of neurones in the basal ganglia, globus pallidus, and more diffusely in the cortex. A DNA marker, G8 (or D4S10), is tightly linked to Huntington's disease and this gene has been localized to chromosome 4 (ref. 3). The discovery of this linkage marker raises the possibility of developing a presymptomatic test for the disorder, and of eventually isolating the disease gene based on its map position. We have now regionally localized the DNA marker G8 to the terminal band of the short arm of the chromosome, a region representing approximately 0.5% of the total human genome. The assignment was made by examining DNA from patients with Wolf-Hirschhorn syndrome, a birth defect resulting from partial heterozygous deletion of the short arm of chromosome 4.