The effect of the apolipoprotein E (APOE) epsilon 4 allele on age of onset was analyzed in two groups of families with early-onset Alzheimer's disease (AD), (1) Volga German (VG) kindreds, in which AD is caused by an unknown locus and (2) early-onset non-VG families showing evidence of linkage to chromosome 14.
Several missense mutations causing early-onset Alzheimer's disease (AD) have been described in the gene coding for the beta-amyloid precursor protein (beta APP).
We have recently determined the intron/exon structure of the PS-1 gene and this information has been used to identify a mutation in the splice acceptor site for exon 9 in a family with early onset AD.
Molecular genetic analysis was performed in two autopsy-confirmed cases of early-onset Alzheimer's disease belonging to a large German pedigree [FAD2, according to the nomenclature of St. George-Hyslop, et al.(1987) Science 235:885-890].
The 15 exons and the promoter region of the DLST gene were analysed for mutations in chromosome 14 linked AD cases and in two series of unrelated early-onset AD cases (onset age < 55 years).
Genetic linkage studies have provided significant evidence that a major gene defect, AD3, for familial early-onset Alzheimer's disease (EOAD) is located at chromosome 14q24.3, between the short tandem repeat (STR) markers D14S52 and D14S53 defining a genetic size of 22.7 cM for the AD3 candidate region.
To identify potential intracellular compartments involved in Abeta production, we expressed human APP-695 (APPwt) and APP-695 harboring the Swedish double mutation (APPswe) associated with familial early-onset Alzheimer's disease, in mouse N2a cells.
The presenilin-1 (PS-1)/S 182 gene at chromosome 14q24.3 is, when mutated, the most common disease gene in autosomal dominant early-onset Alzheimer's disease.
We have found a significantly lower frequency of the presenilin-1 (PS-1) intronic polymorphism 2/2 genotype in early-onset Alzheimer's disease (AD) patients without APOE epsilon4 alleles (2/2 = 0.054; P = 0.009) as compared to age matched non-epsilon4 controls (2/2 = 0.227).
We report a novel mutation in the amyloid precursor protein gene (APPI716V) which probably leads to familial early onset Alzheimer's disease with an onset age in the mid 50s.
While the D14S43 and FOS loci showed no association with either early- or late-onset AD, late-onset AD carrying no APOE-epsilon4 allele was associated with the G allele of the T/G polymorphism located at intron 9 of the PS1 gene (P = 0.016).
These kindreds form the largest collection of AD cases with the same PS-1 mutation and the same educational, environmental, and ethnic background in which to study the phenotypic effect of putative risk factors, such as the epsilon4 allele of apolipoprotein E (ApoE) or head trauma.