Background: Anti-müllerian hormone (AMH) is a surrogate marker of fertility; higher levels are associated with greater ovulatory potential. This study examined AMH levels of BRCA1 and BRCA2 mutation carriers and their non-carrier blood relatives.
Methods: Eligible women were from families segregating BRCA1 or BRCA2 mutations, enrolled in the Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer (kConFab). Each woman had been tested for the family mutation, had completed an epidemiological questionnaire and provided a blood sample at cohort entry. Women were aged 25-45 years, with no personal history of invasive cancer, had not undergone oophorectomy and were not pregnant or breastfeeding at the time of blood draw. AMH was tested on stored plasma samples using an electrochemiluminescence immunoassay platform. Associations between AMH level and carrier status were tested by linear regression, using the natural logarithm of AMH as the outcome variable, carrier status as the explanatory variable, and adjusting for age at blood draw, oral contraceptive use, BMI and cigarette smoking.
Results: AMH level was measured for 693 women, 172 carriers and 216 non-carriers from families carrying BRCA1 mutations, and 147 carriers and 158 non-carriers from families carrying BRCA2 mutations. Within both groups, mutation carriers were younger at blood draw than non-carriers (p ≤ 0.031). BRCA1 mutation carriers had, on average, 25% lower AMH levels than non-carriers (p = 0.022). There was no evidence of an association for BRCA2 mutation carriers (p = 0.94).
Conclusions: This study suggests that women with a germline mutation in BRCA1 may have reduced ovarian reserve. This could have implications for their fertility, family planning and age at menopause.