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Volume 08
Journal of Alzheimers Disease & Parkinsonism
Alzheimer's Congress 2018
May 30-31, 2018
May 30-31, 2018 Osaka, Japan
10
th
World Congress on
Alzheimer's Disease & Dementia
Genetics and epidemiological studies of dementia of alzheimer’s type among Arab populations
Bowirrat Abdalla
EMMS Hospital, Israel
Objective:
To study the genetic and environmental risk factors and the prevalence of Dementia of the Alzheimer Type (DAT)
among the elderly in an Arab community in Israel.
Material & Method:
Epidemiological and genetic studies of dementia have rarely been reported in an Arab population.
Alzheimer disease (AD [MIM #104300]) is a progressive, neurodegenerative disease characterized clinically by gradual loss of
memory and pathologically by neurofibrillary tangles and amyloid plaques in the brain. We have observed an unusually high
prevalence of dementia of the Alzheimer type in Wadi Ara, an inbred Arab community in northern Israel comprising <850
persons over the age of 60 years. Apolipoprotein E (APOE- ε4), has been established as a strong susceptibility marker that
accounts for nearly 30% of the risk in late-onset AD.
Result:
Remarkably, in our study DAT is not associated with APOE, because the frequency of the ε4 allele is very low in both
nondemented (2.4%) and demented elders (3.6%). We also map chromosomal loci contributing to DAT susceptibility; we
conducted a 10 cMscan in a series of twenty cases and twenty controls selected fromone hamula. Markers from18 chromosomal
regions showed significant allelic association with DAT (P<0.05). Locations on chromosomes 2, 9 and 10 remained significant
after testing additional affected and non-demented individuals. Significant associations were also observed for markers on
chromosome 12 which overlap with a locus implicated in previous genome scans. Additionally, several lines of evidence
support for a role of angiotensin converting enzyme (ACE) in Alzheimer Disease (AD). Most genetic studies have focused on
an Alu insertion/deletion (I/D) polymorphism in the ACE gene (DCP1) and have yielded conflicting results. We evaluated the
association between 15 (SNPs) in DCP1, including the I/D variant and AD in a sample of 92 patients with AD and 166 non-
demented controls from an inbred Israeli Arab community. Although there was no evidence for association between AD and
I/D, we observed significant association with SNPs rs4343 (P=0.00001) and rs4351 (P=0.01).
Conclusion:
In Wadi Ara, the high prevalence may be due to a founder effect enhanced by consanguinity which make this
population attractive for investigating DAT susceptibility recessive genes. Thus, a specific disease susceptibility allele may be
overrepresented in cognitively impaired subjects compared with cognitively healthy residents. Other two main conclusions
can be drawn from the genome-wide linkage and Linkage Disequilibrium (LD) studies. Firstly, multiple genes are involved
in DAT. Secondly, there is a high level of consistency among linkage and association studies regarding the general location of
putative AD genes. However, the general location of putative AD genes on a given chromosome covers a broad region which
may contain several genes.
bowirrat@gmail.comJ Alzheimers Dis Parkinsonism 2018, Volume 8
DOI: 10.4172/2161-0460-C4-046