Genetic Diversity among the Arabs

Abstract

The Arabs in general are genetically diverse. Major factors that contributed to their diversity include the migrations of Semitic tribes from the Arabian Peninsula, the Islamic expansion in the 7th century AD, the Crusade wars and the recent migration dynamics. These events have resulted in the admixture of the original Arabs with other populations extending from east and south Asia to Europe and Africa. Their demographic features include high rates of consanguinity, a large family size and a rapid population growth. There is a high frequency of autosomal recessive disorders and increased frequencies of homozygosity for autosomal dominant traits, such as familial hypercholesterolemia and X-linked traits, such as glucose-6-phosphate dehydrogenase deficiency. The patterns of autosomal recessive disorders, including their mutations, may be different in various geographic locations within the Arab world. However, there are disorders that are specifically prevalent among the Arabs either uniformly or in certain locations. The Arab Genetic diseases include Bardet-Biedl syndrome, Meckel syndrome, autosomal recessive severe childhood muscular dystrophy, osteopetrosis and renal tubular acidosis, Sanjad-Sakati syndrome and others.

Spectrum ofMKS1andMKS3mutations in Meckel syndrome: a genotype-phenotype correlation

“…MKS is also frequent in Maghreb and in the Middle East. The highest prevalence is observed in Arab populations: 1/3500 in Kuwaitians, 1/5000 in Omanis and Palestinians (Zlotogora, 1997, Al-Gazali, et al, 2005Teebi and Teebi, 2005). The homozygous p.Q350X homozygous mutation in two unrelated Palestinian families (families 4 and 5), suggested a founder effect, but three affected individuals from two families are not sufficient to estimate accurately the age of the mutation.…”

Consanguinity and Its Effect on Morbidity and Congenital Disorders Among Arabs in Israel

“…2007; Tadmoure et al, 2009;Teebi, 2010, as cited in Teebi, 2010. A strong association between most of the examined disorders and consanguinity was demonstrated in the present study; approximately 56% of the children with one or more disorders were the offspring of consanguineous marriages, and in approximately 68% of these marriages the parents were first cousins or closer.…”

“…When a new mutation is inserted in such a population it spreads rapidly, leading to an increased prevalence of carriers and a large number of affected homozygous individuals. There are high frequencies of genetic diseases and congenital disorders among Arab populations (Tadmouri et al, 2009;Teebi & S.A. Teebi 2005). The high rates of genetic diseases and congenital disorders in the Arab populations can be attributed to several factors including: a) The high rate of traditional consanguineous marriages, which increases the frequency of autosomal recessive diseases; b) a relatively high birth rate of infants with chromosomal disorders related to advanced maternal age such as Down Syndrome and other trisomies; c) a relatively high birth rate of infants with malformations due to new dominant mutations related to advanced paternal age; d) large family sizes, which may increase the number of affected children in families with autosomal recessive conditions; and e) the lack of public health measures directed at the prevention of congenital and genetically determined disorders, and the shortage of genetic services and inadequate health care prior to and during pregnancy (Al-Gazali et al, 2006;Teebi, 2010, as cited in Teebi, 1010.…”

“…Thus, in Arab populations, several recessive diseases like Cystic Fibrosis, Phenylketonuria, Beta Thalassemia and Wilson disease are very frequent. However, due to the tribal society style life among Arab and consecutive genetic founder effects, the distribution of autosomal recessive disorders among the Arab populations is not uniformly distributed, but shows large geographic differences (Teebi & S.A. Teebi 2005;Zolotogora 2002). Consanguinity has been recognized as the main social factor related to a high prevalence of genetic and congenital disorders in Arab communities' worldwide (Bener et al, 2007 Teebi, 2010;Jaber et al, 1992;Sharkia et al, 2010;Zlotogora, 1997).…”

Mental retardation and consanguinity in a selected region of the Israeli Arab community

“…Consanguinity has been recognized as the main social factor leading to a high prevalence of genetic and congenital disorders [1]. Consanguinity is particularly common in Arab communities worldwide [2,3]. In the Arab community in Israel it is a major problem and contributes to the high number and prevalence of genetic diseases, congenital malformations, and neonatal mortality [4,5].…”