Age-at-onset linkage analysis in Caribbean Hispanics with familial late-onset Alzheimer's disease.

The Taub Institute on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY 10032, USA.
Neurogenetics (Impact Factor: 2.66). 03/2008; 9(1):51-60. DOI: 10.1007/s10048-007-0103-3
Source: PubMed

ABSTRACT The aim of the study was to identify chromosomal regions that may harbor putative genetic variants influencing age at onset in familial late-onset Alzheimer's disease (LOAD). Data from a genome-wide scan that included genotyping of APOE were analyzed in 1,161 individuals from 209 families of Caribbean Hispanic ancestry with a mean age at onset of 73.3 years multiply affected by LOAD. Two-point and multipoint analyses were conducted using variance component methods using 376 microsatellite markers with an average intermarker distance of 9.3 cM. Family-based test of association was also conducted for the same set of markers. Age at onset of symptoms among affected individuals was used as the quantitative trait. Our results showed that the presence of APOE-epsilon4 lowered the age at onset by 3 years. Several candidate loci were identified. Using linkage analysis strategy, the highest logarithm of odds (LOD) scores were obtained using a conservative definition of LOAD at 5q15 (LOD = 3.1), 17q25.1 (LOD = 2.94), 14q32.12 (LOD = 2.36), and 7q36.3 (LOD = 2.29) in a model that adjusted for APOE-epsilon4 and other covariates. Both linkage and family-based association identified 17p13 as a candidate region. Family-based association analysis showed markers at 12q13 (p = 0.00002), 13q33 (p = 0.00043), and 14q23 (p = 0.00046) to be significantly associated with age at onset. The current study supports the hypothesis that there are additional genetic loci that could influence age at onset of late onset Alzheimer's disease. The novel loci at 5q15, 17q25.1, 13q33, and 17p13 and the previously reported loci at 7q36.3, 12q13, 14q23, and 14q32 need further investigation.

Download full-text


Available from: Joseph H Lee, Jul 04, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Recent studies indicated sortilin-related receptor 1 (SORL1) to be a risk-gene for late-onset Alzheimer's Disease (AD), although its role in the aetiology and/or progression of this disorder is not fully understood. Here, we report the finding of a novel non-coding (nc) RNA (hereafter referred to as 51A) that maps in antisense (AS) configuration in intron 1 of SORL1 gene. 51A expression drives a splicing shift of SORL1 from the synthesis of the canonical long protein variant 1 to an alternatively spliced protein form. This process, resulting in a decreased synthesis of SORL1 variant 1, is associated with an impaired processing of APP, leading to increase of Aβ formation. Interestingly, we found that 51A is expressed in human brains, being frequently up-regulated in cerebral cortices from Alzheimer's disease patients. Altogether these findings document a novel ncRNA-dependent regulatory pathway that might have relevant implications in neurodegeneration.
    Disease Models and Mechanisms 03/2013; 6(2):424-433. DOI:10.1242/dmm.009761 · 5.54 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The frequency and clinical and pathological characteristics associated with the Gly206Ala presenilin 1 (PSEN1) mutation in Puerto Rican and non-Puerto Rican Hispanics were evaluated at the University of Pennsylvania's Alzheimer's Disease Center. DNAs from all cohort subjects were genotyped for the Gly206Ala PSEN1 mutation. Carriers and non-carriers with neurodegenerative disease dementias were compared for demographic, clinical, psychometric, and biomarker variables. Nineteen (12.6%) of 151 unrelated subjects with dementia were discovered to carry the PSEN1 Gly206Ala mutation. Microsatellite marker genotyping determined a common ancestral haplotype for all carriers. Carriers were all of Puerto Rican heritage with significantly younger age of onset, but otherwise were clinically and neuropsychologically comparable to those of non-carriers with AD. Three subjects had extensive topographic and biochemical biomarker assessments that were also typical of non-carriers with AD. Neuropathological examination in one subject revealed severe, widespread plaque and tangle pathology without other meaningful disease lesions. The PSEN1 Gly206Ala mutation is notably frequent in unrelated Puerto Rican immigrants with dementia in Philadelphia. Considered together with the increased prevalence and mortality of AD reported in Puerto Rico, these high rates may reflect hereditary risk concentrated in the island which warrants further study.
    Journal of Alzheimer's disease: JAD 10/2012; 33(4). DOI:10.3233/JAD-2012-121570 · 3.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Alzheimer's disease (AD) is a genetically complex and heterogeneous disorder. To date four genes have been established to either cause early-onset autosomal-dominant AD (APP, PSEN1, and PSEN2(1-4)) or to increase susceptibility for late-onset AD (APOE5). However, the heritability of late-onset AD is as high as 80%, (6) and much of the phenotypic variance remains unexplained to date. We performed a genome-wide association (GWA) analysis using 484,522 single-nucleotide polymorphisms (SNPs) on a large (1,376 samples from 410 families) sample of AD families of self-reported European descent. We identified five SNPs showing either significant or marginally significant genome-wide association with a multivariate phenotype combining affection status and onset age. One of these signals (p = 5.7 x 10(-14)) was elicited by SNP rs4420638 and probably reflects APOE-epsilon4, which maps 11 kb proximal (r2 = 0.78). The other four signals were tested in three additional independent AD family samples composed of nearly 2700 individuals from almost 900 families. Two of these SNPs showed significant association in the replication samples (combined p values 0.007 and 0.00002). The SNP (rs11159647, on chromosome 14q31) with the strongest association signal also showed evidence of association with the same allele in GWA data generated in an independent sample of approximately 1,400 AD cases and controls (p = 0.04). Although the precise identity of the underlying locus(i) remains elusive, our study provides compelling evidence for the existence of at least one previously undescribed AD gene that, like APOE-epsilon4, primarily acts as a modifier of onset age.
    The American Journal of Human Genetics 11/2008; 83(5):623-32. DOI:10.1016/j.ajhg.2008.10.008 · 10.99 Impact Factor