least ∼1.5 kb upstream of c.217_218 delGA to include rs2066734. This result also confirms that the maternal allele, containing the c.217_218 delGA deletion as well as the minor rs2066734 allele, is lost in Q3SC and is replaced by a copy of the paternal allele sequence, explaining the absence of mutation at this position. Because mutation at c.7792 is heterozygous, reversion of c.217_218 delGA to wild-type sequence would be sufficient to produce a genotype of ATM+/−.
