[The search for a mutation in the gene coding the beta-amyloid protein precursor gene in patients with Alzheimer-type dementias].

Missence mutation in codon 717 of the amyloid precursor protein (APP) gene that codes for the precursor to the beta-protein found in the amyloid deposits of Alzheimer disease was recently shown to be segregated with this disease in some kindreds. The following study aimed to determine the frequency of the codon 717 mutation in familial and "sporadic" cases of dementia of the Alzheimer type has been performed in Russian patients. 62 patients with senile dementia and the Alzheimer disease with early and late onset and 43 normal controls were tested for this mutation. None of them were positive. Thus this mutation is considered to be rare in studied population though in some cases it may be the cause of the disease.