A guide to fragile sites on human chromosomes.

This is a guide to 107 fragile sites, all those considered at the most recent International Workshop on Human Gene Mapping, HGM 9.5, held in 1988. The chromosome band locations of all 107 fragile sites are given, together with their gene symbols, frequency, mode of induction, and status. The majority of these fragile sites are common ones induced to expression by aphidicolin. Fragile sites are nonrandomly distributed within the genome. Chromosome 3 is especially short of known fragile sites. Chromosome 21, the chromosome triplicated in Down syndrome, has no known fragile sites.