Genetic studies on Arabs

Centre for Arab Genomic Studies (CAGS) in Dubai (United Arab Emirates) published a report claiming that Arab countries have one of the highest rates of genetic disease in the world. Some 906 genetic disorders have been identified in Arab countries. Several common diseases in the UAE, Oman and Bahrain have reached epidemic levels - more than 100 cases per 100,000. They include thalassaemia (a blood disorder), diabetes, breast cancer and Down's syndrome. Arab countries have the highest prevalence of birth defects in the world of Tourette's syndrome, Wilson's disease, Charcot-Marie-Tooth disease, mitochondrial encephalomyopathies and Niemann-Pick disease.^[1][2]

Genetic diseases Databases in Arabic countries and studies

Several organizations maintain databases for each Arabic country.

CAGS is the main organization based in UAE. CAGS or the Centre for Arab Genomic Studies initiated a pilot project to construct the "Catalogue for Transmission Genetics in Arabs" (CTGA) database for genetic disorders in Arab populations. At present, the CTGA database, centrally maintained in Dubai, hosts entries for nearly 1540 Mendelian disorders and related genes and this number is increasing as researchers are joining the largest Arab scientific effort to define genetic disorders described in the region. The Center promote research studies on these emergent disorders. ^[3] Some of the challenges are: Hemoglobinopathy, sickle cell anemia, glucose-6-phosphate dehydrogenase deficiency, and fragile X syndrome (FXS) which is an inherited genetic condition with critical consequences. The Centre provide information about specific countries,^[4] and maintain a list of Genomic diseases.^[5][6][7]

Specific rare autosomal recessive diseases are high in Arabic countries like Bardet Biedl syndrome, Meckel syndrome, congenital chloride diarrhea, severe childhood autosomal recessive muscular dystrophy (SMARMD) Lysosomal storage diseases and PKU are high in the Gulf states. Dr Teebi's book provides detailed information and by country.^[8] Even the Middle East respiratory syndrome coronavirus (MERS-CoV) that was first identified in Saudi Arabia last year, it has infected 77 people, mostly in the Middle East and Europe. Forty of them - more than half - have died. But MERS is not yet a pandemic, could become pervasive in genetic disease patient. ^[9]

Dr Thurman' guidebook about Rare genetic diseases ^[10] another book Arabic genetic disorders layman guide^[11] Suadi Journal article about genetic diseases in Arabic countries^[12] The highest proportion of genetic disorders manifestations are: congenital malformations followed by endocrine metabolic disorders and then by Neuron disorders (such as Neuromotor disease)and then by blood immune disorders and then neoplasms. The Mode of Inheritance is mainly autosomal recessive followed by autosomal dominant. Some of the diseases are beta-thalassemia mutations, sickle-cell disease, congenital heart-disease, glucose-6-phosphate dehydrogenase deficiency, alpha-thalassemia, molecular characterization, recessive osteoperosis, gluthanione-reducatsafe DEf. A study about sickle cell anemia in Arabs^[13] article about Birth defects ^[14] 6Glucose Phisphate isomere deficiency responsible for unexpected hemolytic episodes.^[15] one of late Dr Teebi's syndromes.^[16] flash cards guide. ^{[17][18][19][20]} NY times article^[21] In Palestinian Arabs study^[22] study about potential on pharmacology ^[23] another study on Arab Palestinians^[24] Database of Genetic disorders in Arabs study^[25] In Palestinians^[26] new general study about databases^[27] Database for B thalassemia in Arabs^[28] Israeli National genetic bank contains genetic mutations of Arabs^[29] Teebi database 2002^[30] 2010 genes responsible for genetic diseases among Palestinian Arabs^[31][32] The next Pan-Arab conference Nov 2013 ^[33]

Diagnosis of genetic disorders

Diagnosis if genetic disorders after birth is done by clinicians and lab tests and some time genetic testing. Genetic testing profiling screening of pregnant women' fetus for List of disorders included in newborn screening programs using Microchip Genetic Microarrary might help detect genetic mutations incompatible with life and determining abortion. Some genetic tests of born children might help finding the right treatment.^[34][35] Mothers could test for genetic disorders in the fetus by method of chorionic villus sampling (CVS) or amniocentesis.

Genealogy and geographic of Arabic genetic diseases

Bare lymphocyte syndrome high in western Arabic block Morocco, type II Limb-girdle muscular dystrophy, type 2C in Libya, Hemolytic-uremic syndrome in Saudia, Ankylosing spondylitis in Egypt &East block, Alpha-thalassemia in all countries minus Egypt Syria Iraq, Cystic Fibrosis in Iraq Saudi Yemen Libya Morocco, Familial Mediterranean Fever fmf in east block and Libya Morocco, beta Thalassemia in all countries, g6dh deficiency all countries.^[18][36]

Most of the genetic markers of Arabs genetic diseases are phenotypic i.e. specific mutations of Arab peoples, especially in countries. Even though genetic mutations of Gulf states are mostly the same, but some genetic phenotypes are Kuwaiti etc.

The diseases have geographical distribution among Arab countries such as greater Syria, Gulf states, Yemen, Western block (Morocco, Algeria, Tunisia), because of the restrictid marriages to each block or even to one country. Moreover, cousin marriages (conseigenity)and endogamy (marriages restricted to minority sects) excaberate the problem. Distancing of marriages from distant gene pools might help resolve the problem in Arabic countries. Many of the pronounced genetic deficiencies in Arabs are located on HLA segment on chromosome 6 . This same segment mutations are markers of Arabs in Genealogical and forensic profiling tests and studies. Such studies as:^{[14][37][38][39][40]} Arab population data on the PCR-based loci:HLA ^[41] HLA polymorphism in Saudi.^[42]

Since over 70% of Arab genetic disorders are Autosomal-recessive, meaning the defective gene has to be found in both father and mother, and since the gene pool are similar in population (males and females alike since autosomal chromosomes are admixture from father and mother, in closed societies (marriages from same sect endogamy, or same tribe or even from same country, or even from same block of countries since gene pool is similar in Geographical blocks as shown in the online brocures referenced above.^[43] Gulf states block diseases are similar including Saudi Arabia, while Yemen is a different block, Greater Syria is different, Iraq is a different block, while Morocco and Algeria and Tunisia are one different block (the west), etc. The cause of high incidence of genetic disorders is that the Paternal ancestry is homogeneous across all Arab countries while Maternal ancestry is very diverse (a good feature ) but still is different among the aforementioned blocks. The original Historical Maternal ancestral Haplogroups of the Near East were L3 and HV1 still high in Yemen, while in Greater Syria there is a European Maternal gene flow. In the Arabic West the dominant Maternal lineage is the rare Scandinavian European U8 haplogroup probably came with the Vandals when escaped from Spain from the Visigoths. Distancing marriages as far as possible will prevent most Autosomal recessive disorders and other disorders by diluting and mixing the gene pool of the child. The Paternal Ancestry across all Arabic countries is Haplogroup J1 especially the its major subclade J1-P58 the haplogroup that spread with Arabic conquest in the 7th century. It was found that Haplogroup J1 occur at high frequencies among the Arabic-speaking populations of the Middle East and is the prevalent Y-chromosome lineage within the Near East. Haplogroup J1e (J-P58) is also associated with a Semitic linguistic common denominator, with the YCAII 22-22 allele state is closely associated with J1e.^[44] J-P58 subclade of J1 is single paternal lineage originated in the Near East of high frequency in Bedouins 70% Yemenis 68% Jordanians 55%, 55% of Palestinian Arabs, 48% of Omani People 34% of Tunisians, 35% of Algerians, and its precipitations drop in frequency as one moves away from Saudi Arabia and the Near East. J-P58 include all the J1-CMH haplotypes and is YCAII=22-22 motif, both found in Arabs and J1-Cohanim Jews (descendents of Aaron)^[45][46] The motif YCAII=22-22 characterise a monophyletic clad found in Arabs but less frequent in Ethiopian J1 and rare in Europe and Caucasus.^{[47] [48]} It is now been resolved that the Arabic clade J1-P58,L147.1 that include all J1-Cohanim Jews and all CMH haplotypes and is YCAII=22-22. was the J1 clade that spread far and wide by the Islamic conquest ^[49] Both Qahtanite and Adnanite Arabs are J1-P58 haplogroup since the Arabs of North Africa like Algeria (known to have Qahtanite lineage from the Arab conquest and Adnanite lineage from Bani Hilal and bani Sulaim migration to North Africa in the 10th century by the Fatimides, yet only E of the Berber and J1 are found in Arabs of North Africa and this J1 is marked by CMH and the motif YCAII=22-22. The J2 in Algerian Arabs is minor 3% and is of the rare J2-M67 of Chechnea rarely found in other Arabic countries and non existent in Arabian Peninsula and Yemen.^[50][51]

Genetic studies on Arabs that lead to discoveries of new syndromes

Teebi type of Hypertelorism (1987) •• Teebi Shaltout syndrome (1989) •• Al Gazali syndrome (1994) •• Megarbane syndrome (2001)

There are even new Arabic names for emerging genetic disorders& syndromes like:

Spectrum of Genetic Disorders in Arabs •• Lebanese type of mannose 6--phosphate receptor recognition defect (1984) •• Algerian type of spondylometaphyseal dysplasia(1988) •• Kuwaiti type of cardioskeletalsyndrome (1990) •• Yemenite deaf-blind hypopigmentation syndrome (1990) •• Nablus mask-like facial syndrome (2000) •• Jerash type of the distal hereditary motor neuropathy (2000) •• Karak syndrome (2003) •• Omani type of spondyloepiphy

Online practical guides for genetic diseases

Genetic disorders in Arabs ^{[18] [19]}

References