Fig 1.
Schema for X-linked inheritance when cancer status is specific to women (all carrier men are effectively disease censored). Two family patterns with a pair of first-degree affected women are the maternal grandmother (MGM) family and the paternal grandmother (PGM) family. Stratton’s paradox implies that PGM families are more likely under X-linkage because a father must pass the variant to all of his daughters. The rates are equal if the variant is autosomal.
Table 1.
Cancer rates given an affected daughter or sister.
Table 2.
Rates of granddaughter cancer in grandmother-granddaughter pairs.
Fig 2.
Representative registry pedigrees.
Ovarian cancers are represented by teal circles, breast cancers by pink circles, prostate cancers by blue squares and prophylactic oophorectomies by grey circles. The earliest of age of onset, prophylaxis, death or last follow up is indiciated below individuals as well as oophorectomies (ooph.) and one heterozygous variant carrier (A/G).
Table 3.
Age-of-onset by genotype and familial pattern.