ATM and breast cancer: While not all studies of ATM gene mutations demonstrate an excess risk of breast cancer (FitzGerald et al, 1997; Bebb et al, 1999; Shafman et al, 2000), studies that have screened for missense mutations (Athma et al, 1996; Teraoka et al, 2001) and those that have examined risk among family members of A-T patients (obligate heterozygotes) (Swift et al, 1987, 1991; Pippard et al, 1988; Borresen et al, 1990; Inskip et al, 1999; Olsen et al, 2001) have consistently found an elevated risk.