United Arab Emirates: communities and community genetics

Going Back to Fundamentals: Three Marriageable Actions for Thalassemia and Carrier Population Management

We investigated the impact of three marriageable actions: normal-to-carrier, carrier-to-normal, and carrier-to-carrier marriages on thalassemia and carrier populations. The well-known strategy is limiting the carrier-to-carrier marriage to reduce the thalassemia population. Thus, the other two marriageable actions were often ignored. Other than a simple explanation of their genetic consequences, their important aspect in the thalassemia inheritance mechanism has never been studied at the population level. Moreover, there is no mathematical model investigating problem of interest for blood disorders at the population level. Hence, we developed a mathematical model to examine the possibility of eradication/reduction of thalassemia and carrier populations through each of the three marriageable actions in the long-term. We conducted computer simulations with the demographic data of the United Arab Emirates in which high thalassemia carrier prevalence is identified. We found that promoting more carrier-to-normal marriage will eventually have the same effects on marriage reconsideration for carrier-carrier couples, contributing to the reduction of the carrier population in the long-term. Interestingly, the normal-to-carrier marriage does not necessarily have a similar effect on thalassemia and carrier populations as that of the carrier-to-normal marriage. Thus, the two marriageable actions should be distinguished and also seriously considered in education and public awareness campaigns for thalassemia.

Mucopolysaccharidosis Type I Disease Prevalence Among Patients With Idiopathic Short Stature in Saudi Arabia: Protocol for a Multicenter Cross-sectional Study

Background

Since the underlying cause of idiopathic short stature can indeed be undiagnosed mucopolysaccharidosis type I, it is critical to identify patients with mucopolysaccharidosis type I among screened patients with idiopathic short stature.

Objective

The primary objective of this study is to determine the prevalence of mucopolysaccharidosis type I disease in a high-risk group (ie, patients with idiopathic short stature).

Methods

We plan to perform a multicenter, cross-sectional screening study to primarily assess the prevalence of mucopolysaccharidosis type I disease in patients with idiopathic short stature. All eligible patients will be tested after obtaining written informed consent from their parents and guardians. Eligible patients will be recruited over 18 months from specialty care centers for pediatrics and genetics.

Results

This protocol was approved by the Institutional Review Board of King Fahd Medical City and funded by Sanofi Genzyme Saudi Arabia. We expect to collect data from ≥800 patients, as determined by our sample size calculation.

Conclusions

Saudi Arabia is the largest country in the Arabian Peninsula; it has a population of more than 28 million people. To date, there are no reliable data regarding the incidence and prevalence of mucopolysaccharidosis type I in Saudi Arabia; therefore, future multicenter studies will be needed. Further, the prevalence of an attenuated form of mucopolysaccharidosis type I is largely underestimated in Saudi Arabia due to the absence of an effective newborn screening program. Therefore, the implementation of a nationwide newborn screening program is essential for the accurate estimation of the burden of mucopolysaccharidosis and the early diagnosis of patients.

International Registered Report Identifier (IRRID)

PRR1-10.2196/28619

Variation in 100 relevant pharmacogenes among emiratis with insights from understudied populations

Genetic variations have an established impact on the pharmacological response. Investigating this variation resulted in a compilation of variants in "pharmacogenes". The emergence of next-generation sequencing facilitated large-scale pharmacogenomic studies and exhibited the extensive variability of pharmacogenes. Some rare and population-specific variants proved to be actionable, suggesting the significance of population pharmacogenomic research. A profound gap exists in the knowledge of pharmacogenomic variants enriched in some populations, including the United Arab Emirates (UAE). The current study aims to explore the landscape of variations in relevant pharmacogenes among healthy Emiratis. Through the resequencing of 100 pharmacogenes for 100 healthy Emiratis, we identified 1243 variants, of which 63% are rare (minor allele frequency ≤ 0.01), and 30% were unique. Filtering the variants according to Pharmacogenomics Knowledge Base (PharmGKB) annotations identified 27 diplotypes and 26 variants with an evident clinical relevance. Comparison with global data illustrated a significant deviation of allele frequencies in the UAE population. Understudied populations display a distinct allelic architecture and various rare and unique variants. We underscored pharmacogenes with the highest variation frequencies and provided investigators with a list of candidate genes for future studies. Population pharmacogenomic studies are imperative during the pursuit of global pharmacogenomics implementation.

Genetic and reproductive consequences of consanguineous marriage in Bangladesh

Introduction

This study aimed to assess the prevalence, sociodemographic factors, reproductive consequences, and heritable disease burdens associated with consanguineous marriage (CM) in Bangladesh.

Methods

A total of 7,312 families, including 3,694 CM-families, were recruited from 102 locales of 58 districts of Bangladesh. Using a standard questionnaire, we collected medical history and background sociodemographic data of these families. Family history was assessed by pedigree analysis. Fertility, mortality, secondary sex ratio, selection intensity, lethal equivalents were measured using standard methods.

Results

The mean prevalence of CM in our studied population was 6.64%. Gross fertility was higher among CM families, as compared to the non-CM families (p < 0.05). The rate of under-5 child (U5) mortality was significantly higher among CM families (16.6%) in comparison with the non-CM families (5.8%) (p < 0.01). We observed a persuasive rise of abortion/miscarriage and U5 mortality rates with the increasing level of inbreeding. The value of lethal equivalents per gamete found elevated for autosomal inheritances as compared to sex-linked inheritance. CM was associated with the incidence of several single-gene and multifactorial diseases, and congenital malformations, including bronchial asthma, hearing defect, heart diseases, sickle cell anemia (p < 0.05). The general attitude and perception toward CM were rather indifferent, and very few people were concerned about its genetic burden.

Conclusion

This study highlights the harmful consequences of CM on reproductive behavior and the incidence of hereditary conditions. It essences the need for genetic counseling from premarital to postnatal levels in Bangladesh.

Epidemiology of Thalassemia in Gulf Cooperation Council Countries: A Systematic Review

Background

Thalassemia has a burden on the healthcare systems of many countries. About 56000 conceptions result in thalassemia, globally.

Objective

To assess the epidemiological profile of thalassemia in the Gulf Cooperation Council (GCC) countries.

Methods

A systematic search was conducted in MEDLINE/PubMed (National Library of Medicine), CINAHL, and Embase. Relevant observational studies reporting the epidemiology of thalassemia among the GCC population were selected. Data on the prevalence, frequency, and complications of thalassemia were extracted. The quality of the retrieved studies was assessed according to the Newcastle-Ottawa Quality Assessment Scale.

Results

Eighteen studies (14 cross-sectional studies, two retrospective observational studies, and two retrospective analysis) with a total of 3343042 participants were included in this systematic review. Of the 18 studies, 11 studies were conducted in Saudi Arabia, two in the Kingdom of Bahrain, one in Kuwait, three in the United Arab Emirates (UAE), and one in Qatar. The prevalence of thalassemia among children below five years of age ranged from 0.25% to 33%, while it was 0.9% in children above five years and from 0.035% to 43.3% among adult thalassemia patients. The most-reported risk factors were consanguineous marriage and high-risk marriage. There was a lack of data regarding mortality rates in thalassemia.

Conclusions

Despite the premarital screening and genetic counseling (PMSGC) program for thalassemia, the incidence of high-risk couple marriages in GCC countries cannot be effectively diminished. This study suggested that the PMSGC program should adopt more attention for the high-risk areas, to enhance the level of consciousness about the hemoglobinopathy diseases and the consequences of consanguinity among the at-risk couple.

Population Screening for Hemoglobinopathies

Hemoglobinopathies are the most common single-gene disorders in the world. Their prevalence is predicted to increase in the future, and low-income hemoglobinopathy-endemic regions need to manage most of the world's affected persons. International organizations, governments, and other stakeholders have initiated national or regional prevention programs in both endemic and nonendemic countries by performing population screening for α- and β-thalassemia, HbE disease, and sickle cell disease in neonates, adolescents, reproductive-age adults (preconceptionally or in the early antenatal period), and family members of diagnosed cases. The main aim of screening is to reduce the number of affected births and, in the case of sickle cell disease, reduce childhood morbidity and mortality. Screening strategies vary depending on the population group, but a few common screening test methods are universally used. We discuss the salient features of population-screening programs around the globe as well as current and proposed screening test methodologies.

Frequency of Inborn Errors of Metabolism in a Northeastern Iranian Sample with High Consanguinity Rates

OBJECTIVE

Inborn errors of metabolism (IEMs) are disorders with various manifestations that occur mainly in the pediatric population. In countries where consanguineous marriage is common, the association between consanguinity and IEMs is highly important. No studies have been conducted in Iran examining the impact of consanguinity on IEMs.

METHODS

In this retrospective study, the incidences of metabolic disorders were evaluated for the years 2006 through 2016 in the North East Iran Regional Diagnostic Laboratory (Pardis Clinical and Genetic Laboratory). A total of 13,327 infants with clinical symptoms were referred and investigated for IEMs. Newborn screening was performed on samples from all patients suspected of having IEMs.

RESULTS

Of 13,327 infants examined, 60 different IEMs were diagnosed in 1,118. The most frequent disorders among our patients were glucose-6-phosphate dehydrogenase deficiency (G6PDD) (14.04%), methylmalonic and propionic acidurias (MMA/PA) (9.12%), phenylketonuria (PKU) (8%), and isovaleric acidemia (IVA) (6.98%). A significant difference was found in the prevalence of amino acid disorders between the offspring of consanguineous and those of non-consanguineous parents. No statistically significant differences were found between the 2 groups for organic or fatty acids, carnitine or urine cycles, or lysosomal storage disorders. A total of 707 of the 1,118 infants with metabolic diseases (63.24%) were children of consanguineous parents. These findings show that consanguinity can be an important factor in the inheritance of recessive mutations in a homozygous state.

CONCLUSION

This study found a greater frequency of metabolic diseases in offspring of consanguineous parents than in those of non-consanguineous parents in a population with a high rate of consanguinity.

Significantly elevated foetal haemoglobin levels in individuals with glucose 6-phosphate dehydrogenase disease and/or sickle cell trait: a cross-sectional study in Cape Coast, Ghana

Background

Previously published data have demonstrated that sickle red blood cells produce twice as much reactive oxygen species (ROS) suggesting that co-inheritance of sickle cell disease (SCD) and glucose 6-phosphate dehydrogenase (G6PD) enzymopathy could lead to more severe anaemia during sickling crises. Elevated foetal haemoglobin (Hb F) levels have been shown to have positive modulatory effects on sickling crises and disease outcomes. This study sought to assess how inheritance of G6PD enzymopathy affects the level of Hb F and haemoglobin concentration in adults in steady state.

Methods

This cross-sectional study selected 100 out-patients (41 males and 59 females) visiting the University of Cape Coast hospital, between January, 2016 and May, 2016. Cellulose acetate electrophoresis (pH 8.2–8.6), methaemoglobin reductase test, modified Betke alkaline denaturation methods were used to investigate haemoglobin variants, qualitative G6PD status, and %Hb F levels in venous blood samples drawn from these participants. Data was analysed with GraphPad Prism 6 and SPSS and significance set at p < 0.05.

Results

Forty one percent of the participants demonstrated qualitative G6PD enzymopathy whereas only 10% demonstrated Hb AS type (Sickle cell trait, SCT). 5% of the participants co-inherited SCT and G6PD enzymopathy. %Hb F levels in G6PD deficient males was significantly higher than in G6PD deficient females [(p = 0.0003, 2.696% (males) vs 1.975% (females)], although the %Hb F levels was comparable in non-G6PD deficient individuals. %Hb F levels were significantly elevated in males with SCT only (p < 0.05), or G6PD enzymopathy only (p < 0.0001), or SCT + G6PD enzymopathy (p < 0.0001) compared to males with none of these pathologies even though their respective haemoglobin levels were comparable. Male participants with G6PD enzymopathy + SCT co-inheritance had significantly elevated %Hb F when compared to their counterparts with only G6PD enzymopathy (p < 0.001). Male gender [(p = 0.001, OR: 6.912 (2.277–20.984)] partial defective G6PD enzyme [(p = 0.00, OR: 7.567E8 (8.443E7–6.782E9)] SCT [(p = 0.026, OR: 4.625 (1.196–17.881)] were factors associated with raised %Hb F levels ≥2.5.

Conclusion

The inheritance of G6PD defect and/or SCT significantly elevate %Hb F levels in the steady state even though haemoglobin levels are not affected.

Thalassemia in the United Arab Emirates: Why it can be prevented but not eradicated

Thalassemia is a genetic blood disorder that causes abnormal hemoglobin. Hemoglobin is a protein in red blood cells that carries oxygen and is made of two proteins from four α-globin genes and two β-globin genes. A defect in one or more of these genes causes thalassemia. The treatment of thalassemia mostly depends on life-long blood transfusions and removal of excessive iron from the blood stream. Such tremendous blood consumption puts pressure on the national blood stock in many countries. In particular, in the United Arab Emirates (UAE), various forms of thalassemia prevention have been used and hence, the substantial reduction of the thalassemia major population has been achieved. However, the thalassemia carrier population still remains high, which leads to the potential increase in the thalassemia major population through carrier-carrier marriages. In this work, we investigate the long-term impact and efficacy of thalassemia prevention measures via mathematical modeling at a population level. To our best knowledge, this type of assessment has not been done before and there is no mathematical model that has investigated such a problem for thalassemia or any blood disorders at a population level. By using UAE data, we perform numerical simulations of our model and conduct sensitivity analysis of parameter values to see which parameter values affect most the dynamics of our model. We discover that the prevention measures can contribute to reduce the prevalence of the disease only in the short term but not eradicate the disease in the long term.

β-Thalassemia in Abu Dhabi: consanguinity and tribal stratification are major factors explaining the high prevalence of the disease

Tribalism and consanguineous marriages are common in parts of the world with a high prevalence of the β-thalassemia (β-thal) mutations, and increase the risks of homozygosity for this and other recessive disorders. We explored the frequency of β-thal genes and β-thal carriers in 5672 subjects screened before marriage, of whom 2262 were couples. The mean coefficient of inbreeding (F) in the population was estimated from self-reported relationships to prospective spouses in 383 subjects. Overall frequency of β-thal mutations and β-thal carriers in the population were 1.16 and 2.3%, respectively. Among the 14 largest tribes, β-thal carrier frequencies varied from 0 to 13.6%. The estimated F in the population was 0.022. The expected number of couples needed to be screened to detect one couple who were both β-thal carriers in the non inbreeding (F = 0) and inbreeding (F = 0.022) population was 1858 and 646, respectively. However, among 2262 couples, 10 were both β-thal carriers, i.e., 1 in 226 couples, significantly (p = 0.02) more than expected by taking only inbreeding into account. Although β-thal mutations are relatively rare, the burden of β-thal disease is increased eight-fold by tribalism and consanguinity.

Hemoglobin A2 Lowered by Iron Deficiency and α -Thalassemia: Should Screening Recommendation for β -Thalassemia Change?

Screening for β-thalassemia trait (BTT) relies on measuring hemoglobin (Hb) A₂. Since multiple factors can affect HbA₂ levels, the screening can become unreliable. In 1356 healthy Arabs enrolled into a federally funded premarital BTT screening program, the effects of iron deficiency (ID), α⁺-thalassemia trait, gender, smoking, and tribalism on HbA₂ were studied. The complete blood count and hemoglobin fractions were determined on the entire cohort; serum ferritin (<15 μg/L) in 391 subjects was used to determine ID. BTT was present in 29 (2.1%) subjects (HbA₂ > 3.5%). Among 77(20.3%) subjects with ID, the mean HbA₂ (2.30 ± 0.23%) was 0.2% lower than in subjects without iron deficiency (2.50 ± 0.24%, P < 0.0001). In 65 (38%)/172 subjects with phenotypic α⁺-thalassemia trait, the mean HbA₂ (2.43 ± 0.24%) was 0.13% lower than in subjects without α⁺-thalassemia trait, P < 0.0001. The mean HbA₂ did not differ between males and females, smokers and nonsmokers, and between the tribes. Thus, 35 (2.6%) subjects with HbA₂ between 3.2 and 3.5% were at a risk of false negative diagnosis of BTT. Since iron deficiency and α⁺-thalassemia are both common and both lower HbA₂, modifications in screening recommendations for BTT are proposed.

Epidemiological profile of common haemoglobinopathies in Arab countries

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.

Vitamin D in the Persian Gulf: integrative physiology and socioeconomic factors

Countries of the Persian Gulf region--Bahrain, Iran, Iraq, Kuwait, Oman, Qatar, Saudi Arabia, and United Arab Emirates--have become increasingly modernized, resulting in a transformation of lifestyle based on technology, sedentary activity, lack of sunlight, and unhealthy dietary patterns. These factors have led to a higher prevalence not only of vitamin D undernutrition, but also chronic obesity, insulin resistance, prediabetes, and type 2 diabetes. This review explores the integrative physiologic effects of vitamin D with socioeconomic factors and propose a hypothesis-driven model for their contributions to obesity and diabetes in the Persian Gulf. Further research into these interactions may ultimately lead to novel preventive strategies and therapies for metabolic disorders in this geographic region.

Identification of mutations underlying 20 inborn errors of metabolism in the United Arab Emirates population

Inborn errors of metabolism (IEM) are frequently encountered by physicians in the United Arab Emirates (UAE). However, the mutations underlying a large number of these disorders have not yet been determined. Therefore, the objective of this study was to identify the mutations underlying a number of IEM disorders among UAE residents from both national and expatriate families. A case series of patients from 34 families attending the metabolic clinic at Tawam Hospital were clinically evaluated, and molecular testing was carried out to determine their causative mutations. The mutation analysis was carried out at molecular genetics diagnostic laboratories. Thirty-eight mutations have been identified as responsible for twenty IEM disorders, including in the metabolism of amino acids, lipids, steroids, metal transport and mitochondrial energy metabolism, and lysosomal storage disorders. Nine of the identified mutations are novel, including two missense mutations, three premature stop codons and four splice site mutations. Mutation analysis of IEM disorders in the UAE population has an important impact on molecular diagnosis and genetic counseling for families affected by these disorders.

Hurler disease (mucopolysaccharidosis type IH): clinical features and consanguinity in Tunisian population

Mucopolysaccharidosis type I (MPS I) was a group of rare autosomal recessive disorder caused by the deficiency of the lysosomal enzyme, alpha -L -iduronidase, and the resulting accumulation of undergraded dematan sulfate and heparan sulfate. MPS I patients have a wide range of clinical presentations, that makes it difficult to predict patient phenotype which is needed for genetic counseling and also impedes the selection and evaluation of patients undergoing therapy bone marrow transplantation.

AIM OF THE STUDY

consanguinity rates have been determined among 14 families with mucopolysaccharidosis type I, seen in the pediatric departments of different geographic areas of Tunisia (Central and Southern areas) for the period August 2004 - August 2011 in order to investigate the relation between consanguinity and this disorder.

PATIENTS AND METHODS

Clinical and molecular analyses confirmed the diagnosis for MPS type I in the studied families.

RESULTS

Most of the Tunisian MPS I patients have been identified at the homozygous status: p.P533R mutation (7 homozygous and one double heterozygous p.L578Q/p.P533R patients; 41.66% of all the investigated MPSI patients), p.F177S (1 homozygous patient; 5.55%), p.L530fs (1 patient; 5.55%), p.Y581X (2 patients; 11.11%), p.F602X (3 patients; 16.66%), p.R628X (1 patient; 5.55%). Another mutation: p.L578Q has been identified at the heterozygous status in the only double heterozygous p.L578Q/p.P533R case. Part of the mutations was the result of a founder effect. These described points are the consequences of the high rate of consanguinity.

CONCLUSION

The high frequency of p.P533R mutation could be explained by the high degree of inbreeding. This is due to the richness of the genetic background of the studied population.A multidisciplinary approach is essential to develop adequate preventive program adapted to the social, cultural, and economic context.

Global Public Health and the United Arab Emirates

The United Arab Emirates (UAE), as a rapidly developing country in the Middle East, is in a good position to contribute to global health. It can share its experience of dealing with public health problems characteristic of a desert environment, and it can learn from the experience of other nations in tackling challenges posed by globalization. The health issues particular to the region include heat stress, the effects of consanguineous marriages on families and society, and exposure to occupational and environmental hazards. As in many other developed countries, the UAE also has public health problems associated with smoking, road traffic accidents, and obesity. The experience of other countries in dealing with infectious diseases has helped the UAE implement preventive measures to cope with infections such as the recent H1N1 pandemic. International collaboration has advantages to the UAE in managing problems pertaining to global public health.

Consanguinity and major genetic disorders in Saudi children: a community-based cross-sectional study

BACKGROUND AND OBJECTIVES

There is a high rate of consanguinity in Saudi Arabia; however, information on its relationship with genetic disorders is limited. The objective of this cross-sectional study was to explore the role of consanguinity in genetic disorders.

SUBJECTS AND METHODS

The study sample was determined by a multistage probability random sampling procedure. Consanguinity status was obtained during household visits. Primary care physicians performed a history and physical examination of all children and adolescents younger than 19 years, and all cases of genetic diseases were recorded. The chi-square test was used to compare proportions.

RESULTS

During the two-year study period (2004-2005), 11 554 of 11 874 (97%) mothers answered the question on consanguinity, and 6470 of 11 554 (56%) were consanguineous. There was no significant association between first-cousin consanguinity and Down syndrome (P=.55). Similarly, there was no significant association with either sickle cell disease (P=.97) or glucose-6-phosphate dehydrogenase deficiency (P=.67) for first-cousin consanguinity. A borderline statistical significance was found for major congenital malformations (P=.05). However, the most significant association with first-cousin consanguinity was congenital heart disease (CHD) (P=.01). Finally, no significant association was found for type 1 diabetes mellitus (P=.92). For all types of consanguinity, similar trends of association were found, with a definite statistically significant association only with CHD (P=.003).

CONCLUSION

The data suggest a significant role of parental consanguinity in CHD. However, a relationship between consanguinity and other genetic diseases could not be established. The effect of consanguinity on genetic diseases is not uniform and this should be taken into consideration in genetic counseling.