Evidence of different complementation groups amongst human genetic disorders characterized by radiosensitivity

The genetic diversity of a clinically heterogeneous group of ionizing radiation-sensitive human mutants has been examined. In this group, the relationship between ataxia telangiectasia (A-T), Alzheimer's disease (AD) and Down's syndrome (DS) was studied, on the basis of their cellular radiosensitivity. Cell-fusion analysis was used to determine the presence of different complementation groups. In a series of 4A-T, 5AD and 4DS cell lines, 8 complementation groups were documented. These findings suggest that this group of primary neuronal degenerative disorders might have some overlap in their genetic defects.