Geriatric Neurogenetics: Oxymoron or Reality?

Background Primary genetic diseases are generally associated with pediatric and young adult populations. Little information is available about the occurrence of single-gene mendelian diseases in elderly populations. Objective To describe the occurrence of single-gene neurogenetic disorders in a group of elderly patients. Design Retrospective review of neurogenetic cases in an academic medical center. Setting Academic university and Veterans Affairs medical centers. Patients Eight elderly patients with single-gene neurogenetic diseases were studied. These patients included an 87-year-old man and an 85-year-old man with Huntington disease, an 84-year-old woman with limb-girdle muscular dystrophy type 2A, a 78-year-old man with spinocerebellar ataxia type 14, an 86-year-old man with spinocerebellar ataxia type 5, an 85-year-old man with a presenilin 1 familial Alzheimer disease mutation, an 87-year-old man with autosomal dominant hereditary neuropathy, and a 78-year-old man with spinocerebellar ataxia type 6. Three patients had no family history of neurologic disease. Main Outcome Measures Medical histories, physical examination results, and genetic testing results. Conclusions Single-gene mendelian neurogenetic diseases can be found in the oldest old population (> 85 years). Such cases are currently underrecognized and will become more commonly observed in the future. This phenomenon is a result of (1) the aging of the general population, (2) better recognition of the highly variable ages at onset of genetic diseases, and (3) the availability of specific DNA-based genetic testing.