Maternal transmission of Alzheimer disease

Some researchers propose maternal Alzheimer disease (AD) inheritance. We compared dementia family histories in AD cases and cognitively normal controls. We expected more mothers to have AD in both groups. If maternal risk was not only due to female longevity, more AD cases' than controls' mothers should have dementia. We matched 196 AD cases to 200 controls by sex and age. We obtained parent dementia status and age of death for 348 AD and 319 control parents. Twenty-four (12%) controls' fathers, 26 (13%) AD patients' fathers, 58 (29%) controls' mothers, and 55 (28%) AD mothers had memory difficulty. More mothers than fathers had memory problems in both groups and the statistical significance persisted after adjusting for parent age at death and APOE for controls [odds ratios (OR)=2.40, P=0.004] but not cases (OR=1.63, P=0.14), although the results are qualitatively similar. There was no evidence of a real difference between the 2 groups in interaction analysis (P=0.41). Mothers of both cases and controls were more often affected than fathers, even after adjusting for age. Cases' mothers no more often had dementia than controls' mothers, which does not support maternal AD transmission. Rather, the increased number of affected mothers relates, at least in part, to female longevity.