Neurobiology of aging
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Neurobiology of aging · Oct 2013
Evidence that PICALM affects age at onset of Alzheimer's dementia in Down syndrome.
It is known that individuals with Down syndrome develop Alzheimer's disease with an early age at onset, although associated genetic risk factors have not been widely studied. We tested whether genes that increase the risk of late-onset Alzheimer's disease influence the age at onset in Down syndrome using genome-wide association data for age at onset of dementia in a small sample of individuals (N = 67) with Down syndrome. We tested for association with loci previously associated with Alzheimer's disease risk and, despite the small size of the study, we detected associations with age at onset of Alzheimer's disease in Down syndrome with PICALM (β = 3.31, p = 0.011) and the APOE loci (β = 3.58, p = 0.014). As dementia in people with Down syndrome is relatively understudied, we make all of these data publicly available to encourage further analyses of the problem of Alzheimer's disease in Down syndrome.
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Neurobiology of aging · Oct 2013
TREM2 mutations are rare in a French cohort of patients with frontotemporal dementia.
Homozygous mutations in TREM2 have been recently identified by exome sequencing in families presenting with frontotemporal dementia (FTD)-like phenotype. No study has evaluated the exact frequency of TREM2 mutations in cohorts of FTD patients so far. We sequenced TREM2 in 175 patients with pure FTD, mostly French, to test whether mutations could be implicated in the pathogenesis of the disease. ⋯ We did not identify the polymorphism p. R47H (rs75932628), strongly associated with an increased risk of developing Alzheimer's disease. We conclude that TREM2 mutations are extremely rare in patients with pure FTD, although further investigation in larger populations is needed.