The association between consanguinity marriage and thalassemia among UAE parents
THE LITERATURE REVIEW
Research Methods in Healthcare HSC-4003
Laila Hassan H00307981
Reem Adel H00349259
Reem Sulaiman H00349421
Thalassemia considers as major health concern among the UAE nationals as it has one of the highest prevalence in the world with 18.4%. (Haddad,2013). And consanguinity marriage is a common social practice in the UAE with 50.5% of the population and its known for its contribution to the prevalence of thalassemia. (Haddad,2013). Consanguineous marriages defined as a marriage between two spouses who are biologically linked. When two biologically related spouses get married their children have a higher level of homozygosity meaning that the children will receive identical alleles from their parents. In general, thalassemia is inherited as an autosomal recessive. The aim of this literature review is to finds the association between consanguinity marriage and thalassemia. The 5 articles used for this literature review are between 2006 to 2017.
A study was done to find the link between consanguinity marriage and the common genetic disorders in Saudi Arabia. Random sampling was performed to study the Consanguinity status, and a questionnaire was developed for a population of 11874 people who are all parents, and it is concerned with relation, type of marriage (degree of kinship), history and physical examination was conducted on cases of genetic diseases for subjects under 19 years old. Genetic disorders were categorized into 3 groups which are chromosomal (down syndrome), a single gene (SCD and G6PD deficiency), and multifactorial defects (congenital malformations and type 1 diabetes mellitus). The results showed that theres no significant impact of the first-cousin consanguinity and Down syndrome, sickle cell, G6PD disease deficiency, and type 1 diabetes mellitus. However, there was statistical significance for congenital heart disease. (El Mouzan, Al Salloum, Al Herbish, Qurachi & Al Omar, 2008).
On the other hand, another study done on a sample consisted of 5672 subjects, 2262 of them were couples to explore the effects of tribalism and the Consanguinity of the rates of ?-thalassemia in among 14 largest tribes in Abu Dhabi. The participants had attended screening centers for ?- Thalassemia screening. The tests included Complete blood count (CBC) and hemoglobin (Hb) analysis either by high-performance liquid chromatography (HPLC) or capillary electrophoresis or both. The results have found that 2 subjects with ?- Thalassemia disease and 128 subjects ?- Thalassemia trait. Although the overall prevalence of ?- Thalassemia carriers in Abu Dhabi estimated at 2.3% (130/5672), it diverted among the 14 largest tribes. ?-Thalassemia prevalence was 13.6% in one of the 14 tribes, however, it wasnt found in five tribes. The findings suggest that results are indicating the prevalence of ?-Thalassemia mutations and ?-Thalassemia carriers prevalence is among the national population, Abu Dhabi considers moderate. Even though the study came to conclude that tribalism and the consanguinity are contributing to increasing ?-Thalassemia.( Denic, Aden, Nagelkerke & Al Essa, 2013).
Another study reviewed the files of 8109 patients from a genetic clinic in Cairo. The patient ages were between 3 days and 32 years, they represented as genetic disease patients which then the results are compared with consanguinity among 10,000 healthy couples as controls. Cousin marriage has a higher rate than the control group by 19.1% which is considered a very high rate. (Shawky et al., 2013).
A cross-sectional study was done by (Sadiq, Khan. M, Ahmed. Mushtaq, N. Wasim Ullah Shah, M. (2015). at various hospitals in Pakistan showing the association between consanguinity marriage and thalassemia. The result showed that out of 180 subjects 110 (161%) were males and 70(39%) were females. Overall, 133(74%) of thalassemia patient parents were actually closely related, while 47(26%) were unrelated.
Table: Distribution of thalassemic patients in relation to consanguinity and hepatitis C virus
The study of (Sadiq, Khan., et al., 2015). says that consanguinity marriages have reported a high prevalence of the disease than unrelated marriages. The study also mentioned that males were more affected than females with the support of other studies such as a study was conducted in Turkey, reported that 56.7% of patients were male and 43.3% were female.
The number of mutations discovered in each population changes depending on its origin and interaction with other populations. Thalassemia appears unlikely to have arisen because of consanguinity marriage only. However, there are other considerations have also contributed to the worldwide distribution of thalassemia. Such as the resistance to malaria, Consanguinity marriage, Nutrition, infections, and Migration. Globally, malaria distribution has confirmed the close relation between malaria and hemoglobinopathy (HbS and ?-thalassemia). But it is unlikely that thalassemia mutations had arisen after malaria became a major selective factor. , (De Sanctis et al., 2017).
The hypothesis that has been generated assumed that consanguinity marriage contributes to increase thalassemia in the UAE. Three studies demonstrated the existence of this association. On the other hand, one study showed that consanguinity has not uniformly affected all genetic diseases except with only congenital heart disease which shows significant association with consanguinity while the other study shows consanguinity marriage wasn’t the main cause of thalassemia only. Other factors have been suggested and Thalassemia mutations could be well explained by looking at their geographical distribution, consanguinity, the history of malaria, migrations, and wars. (De Sanctis et al., 2017).
Barakat-Haddad, C. (2013). Prevalence of high blood pressure, heart disease, thalassemia, sickle-cell anemia, and iron-deficiency anemia among the UAE adolescent population. Retrieved from
Consanguinity ratio in b-thalassemia major patients in District Bannu. (2015). Journal of Pakistan Medical Association, 65(11). Retrieved from
De Sanctis, V., Kattamis, C., Canatan, D., Soliman, A. T., Elsedfy, H., Karimi, M., Angastiniotis, M. (2017, February 20). ?-Thalassemia Distribution in the Old World: an Ancient Disease Seen from a Historical Standpoint. Retrieved from
Denic, S., Aden, B., Nagelkerke, N., & Al Essa, A. (2013). ?-Thalassemia in Abu Dhabi: Consanguinity and Tribal Stratification are Major Factors Explaining the High Prevalence of the Disease. Hemoglobin, 37(4),. Retrieved from
El Mouzan, M. I., Al Salloum, A. A., Al Herbish, A. S., Qurachi, M. M., & Al Omar, A. A. (2008). Consanguinity and major genetic disorders in Saudi children: a community-based cross-sectional study. Annals of Saudi medicine, 28(3), 169173. doi: 10.5144/0256-4947.2008.169
Rabah M. Shawky, Solaf M. Elsayed, Mouchira E. Zaki, Sahar M. Nour El-Din, Ferihan M. Kamal. (2013). Consanguinity and its relevance to clinical genetics. The Egyptian Journal of Medical Human Genetics.
Year of publication Study Design Study Locations Study
Subjects exposure outcome Measures(s) of exposure Measure(s) of outcome Length of follow up Measurer(s )of Effect Association
, 2008 Cross-sectional Saudi
Arabia saudi parents & children and adolescents (<19 years)
questionnaire history and physical examination
Srdjan Denic, 2013 retrospective study
Abu Dhabi UAE emiratie couples Consanguinity and Tribalism
?-THALASSEMIA interview using a structured questionnaire ?-Thalassemia
screening test(measuring Hb A2 ) 8 months Association
De Sanctis, V,
Catholic University in Rome
ancient disease people
Sadiq Khan, M, 2015 cross-sectional study Pakistan 180 subjects of related & unrelated parents consanguinity marriage Thalassemia major cross-sectional study thalassemia caused by consanguinity marriage June 2013- July 2014 Association
Rabah M.Shawky, 2013 retrospective study Egypt, Cairo 8109 patients from Ain Shams University, Cairo consanguinity
couples Genetic Disorder retrospective study unknown unknown Strong association