Heredity and dementia

This is a study on the heredity of dementia in the ageing of the Alzheimer, vascular and Pick types. The incidence of the same type of dementia among parents, siblings and offspring of the probands is higher than that in the general population. Alzheimer dementia (AD): Presenile familial AD follows a dominant mode of inheritance: many pedigrees with numerous cases in successive generations, and higher incidence of AD among the parents than among the siblings. Senile familial AD seems to follow a recessive mode: pedigree with 2 or more cases usually in only one generation, and higher incidence of AD among the siblings than among the parents. Yet presenile and senile AD cases are sometimes found in the same family. The heredity factors involved in AD may be partially common for the presenile and senile forms. Vascular dementia (VD): In families of VD probands, the incidence of VD and brain strokes is higher in parents than in siblings, and familial vascular cases are more numerous in two generations than in one. A familial diathesis seems to exist for VD, following a dominant mode of inheritance. Pick dementia (PD): The form of brain lobar atrophy of PD with gliosis, argyrophilic inclusions (AI) and/or ballooned neurons (BN), when it is familial, follows a dominant mode of inheritance: many pedigrees with numerous cases in successive generations. The form of PD without AI or BN, but with only gliosis, when it is familial, seems to follow a recessive mode: some pedigrees with 2 or more cases in only one generation.