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P1–318: A novel Alzheimer's disease locus associated with atypical ‘plaque–predominant’ neuropathology
Author(s) -
Luty Agnes A.,
Kwok John B.,
Thompson Elizabeth,
Blumbergs Peter C.,
Brooks William,
Schofield Peter R.
Publication year - 2006
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2006.05.696
Subject(s) - neuropathology , locus (genetics) , genetics , penetrance , senile plaques , biology , genetic linkage , dementia , alzheimer's disease , pedigree chart , disease , gene , pathology , medicine , phenotype
of onset was obtained from caregivers. Differences in age of onset in 33 affected sib-pairs were analyzed in relation to ApoE genotype by one-way ANOVA. Results: 78% of the AD cases were ApoE 4/3 (50%) or 4/4 (28%), while 32% were 3/3. ApoE 4/4 carriers had a younger age at onset (66 5 years, mean SD) than 3/4 (69 7) and 3/3 carriers (71 6) but without statistical difference. The distribution of Apo E concordant sibpairs (n 22) was the following: 3/3 (n 4 sib-pairs, differences in age at onset 7.2 6.4 years), 3/4 (n 11, 4.5 3.0 years), 4/4 (n 7, 6.5 3.4 years). ApoE discordant sib-pairs (n 12) were the following: 3/4 versus 4/4 (n 8 sib-pairs, differences in age at onset 4.2 2.4 years), and 3/3 versus 3/4 (n 4, 5.5 1.9 years). Differences in age at onset in concordant ApoE sib-pairs (5.7 3.9 years) were not significantly different than in discordant sib-pairs (4.6 2.3 years). The presence of an extra ApoE allele in discordant sib-pairs only meant a younger age at onset in half of the pairs. Conclusions: Within sib-pairs with familial AD, ApoE genotype is not a major factor influencing age at onset. Other variables should be considered to influence the great variability in age at onset among affected siblings.