Epidemiological profile of common haemoglobinopathies in Arab countries

Abstract

Haemoglobinopathies including the thalassemias and sickle cell disease are known to be prevalent inherited disorders in most Arab countries with varying prevalence rates and molecular characterisation. β-thalassemia is encountered in polymorphic frequencies in almost all Arab countries with carrier rates of 1-11 % and a varying number of mutations. The most widespread mutation in Lebanon, Egypt, Syria, Jordan, Tunisia and Algeria is the IVS-I-110 (G>A). In the Eastern Arabian Peninsula, the Asian Indian mutations (IVS-I-5 (G>C), codons 8/9 (+G) and IVS-I (−25 bp del)) are more common. The α-thalassemias are encountered in the majority of Arab countries in frequencies ranging from 1 to 58 % with the highest frequencies reported from Gulf countries. The (−α 3.7 ) mutation is the most frequent followed by the non-deletional α2 polyadenylation signal mutation (AATAAA>AATAAG) and the α2 IVS1 5-bp deletion. The rates of sickle cell trait in Arab countries range from 0.3 to 30 %, with the Benin, the Arab-Indian and the Bantu haplotypes constituting the bulk of the haplotypes, leading to two major phenotypes; a mild one associated with the Arab-Indian and a severe one with the Benin and Bantu haplotypes. Public health approaches targeting prevention of haemoglobinopathies in Arab countries include newborn screening for sickle cell disease, and premarital screening for carriers of β-thalassemia and sickle cell disease. These services are still patchy and inadequate in many Arab countries recommending the upgrade of these services with strengthening of the education and training of health care providers and raising public awareness on the feasibility of prevention and care for haemoglobinopathies.

The first five years of a preventive programme for haemoglobinopathies in Northeastern Iraq

“…17 While WHO has recommended that all such screening tests should be voluntary, 18 several countries in the Mediterranean region including Iran, Cyprus, Saudi Arabia, Bahrain, Jordan and Palestinian territories have passed laws making premarital testing for haemoglobinopathies compulsory prior to marriage. 2,19 The rationale for advocating such mandatory testing by the authorities in these countries (and in our region) is the belief that the method is the most effective in decreasing the birth rate of these disorders. In our study, b-thalassemia trait was the most commonly seen haemoglobinopathy, with a carrier rate of 3.98%.…”

“…6,7,15 The prevalence rates for b-thalassaemia vary in surrounding countries, with a range of 2.0% to 5.9% in the Arab countries in the Eastern Mediterranean region to the west and south of Iraq. 2 The overall frequency is 2% in Turkey (to the north of Iraq), and 4%-10% in various regions of Iran (to the East of Iraq). 20,21 Other than b-thalassaemia, haemoglobin disorders, including sickle cell trait and db-thalassaemia trait were not common in our study.…”

“…The carrier rates for b-thalassaemia ranged from 3.7-4.5% in various parts of the country, with some 15,000 registered patients with b-thalassaemia major/intermedia. 2,[5][6][7] Sickle cell disorders were seen mainly in the extreme north and south of the country, with the highest carrier rates in the south reaching up to16% in some localities. 8,9 Such high carrier rates coupled with around a 30% rate of consanguineous marriages, 10 and the limited resources available to the health services, make initiating a preventive programme for these disorders a necessity.…”

Premarital Screening for Hemoglobinopathies: Experience of a Single Center in Kurdistan, Iraq

“…Thalassemia (thal) and sickle cell disease are important public health problems in Middle Eastern countries, including Iraq [1]. These hemoglobinopathies are either due to reduction in the globin chain synthesis (thals) or to the production of abnormal chains (e.g.…”

“…sickle cell disorders) [2]. In Iraq, β-thal is rather uniformly distributed throughout the country with an average carrier rate of around 4% and ∼15,000 registered patients with thal major/intermedia [1,3,4,5]. Sickle cell disorders, on the other hand, are less uniformly distributed with carrier rates varying from 0 to 16.0%, and they cluster in the extreme north and south of the country [6,7].…”