Red cell genetic abnormalities in Peninsular Arabs: sickle haemoglobin, G6PD deficiency, and alpha and beta thalassaemia

β-Thalassemia and Diabetes Mellitus: Current State and Future Directions

β-Thalassemia major is a congenital hemoglobin disorder that requires regular blood transfusion. The disease is often associated with iron overload and diabetes mellitus, among other complications. Pancreatic iron overload in β-thalassemia patients disrupts β-cell function and insulin secretion and induces insulin resistance. Several risk factors, including family history of diabetes, sedentary lifestyle, obesity, gender, and advanced age increase the risk of diabetes in β-thalassemia patients. Precautionary measures such as blood glucose monitoring, anti-diabetic medications, and healthy living in β-thalassemia patients notwithstanding, the prevalence of diabetes in β-thalassemia patients continues to rise. This review aims to address the relationship between β-thalassemia and diabetes in an attempt to understand how the pathology and management of β-thalassemia precipitate diabetes mellitus. The possible employment of surrogate biomarkers for early prediction and intervention is discussed. More work is still needed to better understand the molecular mechanism(s) underlying the link between β-thalassemia and diabetes and to identify novel prognostic and therapeutic targets.

Prevalence and Risk Factors of Choledocholithiasis in Omani Patients With Sickle Cell Disease Undergoing Endoscopic Retrograde Cholangiopancreatography: A Retrospective Analysis

Background Sickle cell disease (SCD) is a prevalent genetic disorder in the Middle East, particularly in Oman, leading to significant morbidity. It is caused by a mutation in the gene encoding hemoglobin (Hb) molecules, resulting in the formation and polymerization of hemoglobin S (HbS), which subsequently leads to hemolysis. Chronic hemolysis in SCD patients often results in various complications, including increased bilirubin levels in the gallbladder and the formation of pigmented biliary stones, which may obstruct the biliary tract system. In such cases, endoscopic retrograde cholangiopancreatography (ERCP) is often employed as a diagnostic and therapeutic tool to manage biliary complications. Objectives and rationale Considering the lack of studies on the Omani population with SCD, our study aims to determine the incidence of biliary stone formation in SCD patients undergoing ERCP and identify associated risk factors. Subjects and methods This retrospective study included 79 SCD patients aged over 12 years who underwent ERCP at Sultan Qaboos University Hospital, Muscat, Oman, between January 2010 and January 2023. Patient data were extracted from medical records. Continuous variables were analyzed using mean and standard deviation calculations, with independent sample t-tests for mean comparisons. The chi-square test assessed associations between categorized variables, with a p-value of ≤0.05 denoting statistical significance. Results The prevalence of choledocholithiasis in SCD patients undergoing ERCP was 67.1%. The incidence was higher in females (68.9%) than males (65.9%), in patients aged 12-29 (71.2%) compared to those aged ≥29 (59.3%), in patients with SCD (70.6%) versus sickle cell thalassemia (66.1%), and in those who had undergone gallbladder removal (80.0%) compared to those who did not (61.3%). Prevalence was also higher in patients not using hydroxyurea and folic acid (70.6% and 84.6%, respectively); however, chi-square analysis showed no significant association (p-value > 0.05). Additionally, t-test comparisons of HbS and HbF levels showed no significant differences. Conclusion This study documents a high prevalence of choledocholithiasis (67.1%) in SCD patients undergoing ERCP. Although the prevalence is notable, the examined risk factors did not show a significant association with stone formation.

The effect of intermittent fasting on the clinical and hematological parameters of patients with sickle cell disease: A preliminary study

Introduction

Sickle cell disease is a genetic disorder that frequently presents with vaso-occlusive crisis (VOC). Most patients with sickle cell disease in Qatar are Muslims; hence, they practice intermittent fasting during the holy month of Ramadan. However, there is a paucity of literature describing the effect of intermittent fasting on the occurrence of severe VOC. As a result, there is a lack of guidelines or standardized protocols that can help physicians advise patients with sickle cell disease who wish to practice intermittent fasting. Therefore, this study's aim was to investigate the effect of intermittent fasting on the clinical and hematological parameters of individuals with sickle cell disease.

Methods

We conducted a retrospective study for 52 Muslim patients with sickle cell disease in Qatar aged ≥18 years who were confirmed to be fasting during the holy month of Ramadan during any of the years 2019-2021. The difference in the occurrence of severe VOC, hemolytic crisis, and other clinical, hematological, and metabolic parameters were studied one month before, during, and one month after the intermittent fasting of Ramadan using the patient's medical records. Mean (sd), median (IQR), and frequency (%) described the data. One-way with repeated measures ANOVA with a Greenhouse-Geisser correction and Friedman tests (^*) were used at alpha level 0.05.

Results

The study participants' (mean±sd) age was (31.1±9.2) years, 51.9% were males, and 48.1% were females. Roughly seventy percent of the participants were of Arab ethnicity, while the rest were either African or Asian. Most of the patients were homozygotes (SS) (90.4%). The median number of severe VOC (P = 0.7) and hemolytic crisis (P = 0.5) was not found to be significantly different before, during, or after Ramadan. Significant differences, however, were found in platelet count (P = 0.003), reticulocyte count (P < 0.001), and creatinine level (P = 0.038) with intermittent fasting.

Discussion

In this preliminary study, intermittent fasting does not seem to influence the rate of occurrence of severe vaso-occlusive crisis or hemolytic crisis in patients with sickle cell disease; however, it was found to be associated with differences in platelet count, reticulocytes count, and creatinine level. The statistical and clinical significance of these findings needs to be confirmed in studies with a larger sample size.

Acute Ischemic Stroke in Sickle Cell Disease Challenges for Thrombolysis

Sickle cell disease (SCD) is a hemoglobinopathy disorder that was recognized in 1949. Stroke is one of the most devastating complications of this disorder. The risk of stroke in SCD patients varies with the genotype; the highest rate has been reported with hemoglobin S. Tissue type plasminogen activator (t PA) is class I recommended therapy for acute ischemic stroke (AIS) since 1996. Although it is unclear if SCD patients were included in the t PA trail, SCD has never been identified as contraindication. The debate of offering t PA for adult SCD patient presenting with AIS continued for at least 2 decades. It is not up and until 2 years ago when the American Heart Association and American stroke association (AHA/ASA) announced that intravenous (IV) t PA can be offered to adult SCD patients presenting with AIS. Here, we report a case where successful IV thrombolytic therapy was offered to an adult SCD patient presenting with AIS with excellent outcome.

Distribution of sickle cell disease and assessment of risk factors based on transcranial Doppler values in the Gulf region

Background/Objective: Stroke is a potentially fatal complication of sickle cell disease (SCD). Transcranial Doppler (TCD) is useful at identifying increased risk of stroke in children with SCD and vasospasm after subarachnoid hemorrhage. The main aim of this study was to determine the proportion of patients with SCD in the Gulf region who are at a high risk of stroke, as determined by TCD.Methods: This multicenter (Oman, Qatar, and UAE), descriptive, cross-sectional study in patients (aged 2-16 years) with SCD included a baseline visit, 1 follow-up visit for patients with conditional TCD, and 3-year retrospective data analysis for all patients.Results: Of the 410 eligible patients (Oman, 86.5%; Qatar, 8.2%; UAE, 5.1%), most had a TCD finding (left side, 91.7%; right side, 92.0%) of normal velocity (<155 cm/s) at baseline. For 6 of 7 patients with conditional velocity (155-179 cm/s) and 1 patient with high velocity (≥180 cm/s), baseline TCD results were not confirmed at follow-up. As per bivariate linear regression, age, race, transfusion type, and transfusion frequency were significant predictors of the TCD velocities. Multivariate logistic regressions revealed that TCD velocities were significantly correlated with sex, race, and type of transfusion. No patients reported any adverse events at follow-up. No deaths occurred during the study.Discussion/Conclusions: The study results show that far fewer patients with SCD in the Gulf have abnormal TCD findings than the internationally reported. Larger studies are needed to identify the factors underlying this observation.

Alpha thalassemia genotypes in Kuwait

Background

The frequency of the alpha thalassemia trait is approximately 40% in the Kuwaiti population, but there has been no comprehensive study of the prevalent alleles. This is a report of patients who were referred for molecular diagnosis over a 20-year period.

Methods

This is a retrospective study of the α-globin genotypes obtained in the Hemoglobin Research Laboratory of the Department of Pediatrics, Kuwait University from 1994 to 2015. Genotyping was performed by a combination of PCR, allele-specific oligonucleotide hybridization and reverse dot blot hybridization (Vienna Lab Strip Assay).

Results

Four hundred samples were characterized and analyzed from individuals aged < 1 month to 80 years, with a median of 6 years from 283 unrelated families. Most (90.8%) were Kuwaiti nationals. The commonest genotype was homozygosity for the polyadenylation-1 mutation (α^PA-1α/α ^PA-1α) in 33.3% of the samples, followed by heterozygosity (αα/α ^PA-1α) for the same mutation in 32.3%. PA-1 was therefore the most frequent allele (0.59). The frequency of the α⁰ (−-^MED) allele was 0.017. Rare alleles that were found in very low frequencies included α⁰ (−-^FIL) in a Filipino child, Hb Constant Spring, Hb Adana, and Hb Icaria.

Conclusion

There is a wide variety of alpha thalassemia alleles among Kuwaitis, but nondeletional PA-1 is by far the most common cause of the moderate to severe HbH (β4 tetramer) disease phenotype. The α⁰ (−^MED) allele is also encountered, which has implications for premarital counseling, especially for the possibility of having babies with alpha thalassemia major (Barts hydrops fetalis).

Hydroxyurea: Pattern of Use, Patient Adherence, and Safety Profile in Patients with Sickle Cell Disease in Oman

OBJECTIVES

Many barriers contribute to the underutilization of hydroxyurea (HU) in the treatment of sickle cell disease (SCD), and adherence to its use is often reported to be suboptimal. It is important to have information on the safety of HU in patients with SCD. Our study assessed the pattern of use, patients' adherence to medication, discontinuation of use, and safety of HU in patients with SCD.

METHODS

This cross-sectional study was conducted in the department of medicine of a referral hospital in Oman over five months and included a review of patient files and patient interview. Approval was obtained from the Regional Research and Ethics Committee of the A'Dakhiliyah Governorate and the hospital administration. The parameters were compared between groups using the chi-square test.

RESULTS

Of 298 patients studied, 128 (43.0%) had used HU at some points. The difference in the prevalence of HU use was statistically significant based only on age (p = 0.014), with younger patients more likely to be currently using HU or used HU in the past. The majority of patients were adherent (82.5%) based on self-reported adherence. The prevalence of discontinuation (temporary or permanent) of HU use was high (57.0%), and suspected adverse drug reaction (ADR) was the most common reason. Among those who had never used HU, 33.7% of patients had an indication for the initiation of HU. A quarter of patients who used HU developed a suspected ADR, with blood abnormalities being the commonest. The duration of HU use influenced ADR prevalence (p = 0.015).

CONCLUSIONS

Among the current users of HU, the majority of the patients were adherent based on self-reported medication adherence. The prevalence of discontinuation of HU use and instances of non-initiation of HU among those indicated were high. A larger study, ideally of a prospective nature, in various governorates of Oman, would provide a wider picture at the national level.

The Sub-Phenotypes of Sickle Cell Disease in Kuwait

Kuwaiti patients with sickle cell disease generally have a mild phenotype, but exhibit considerable heterogeneity, in spite of high Hb F levels. We have carried out a cross-sectional study of patients with sickle cell disease in the five major hospitals in Kuwait. Details of their hemoglobin (Hb) genotypes, clinical presentations and complications are presented. The study was over a span of 3 years and involved 396 patients, made up of 351 (88.6%) Kuwaitis and 45 (11.4%) expatriates. They were aged <1 to 73 years. Hb SS (β^S/β^S) was the most common (in 246 patients, i.e. 62.1%) followed by Hb S (HBB: c.20A>T)-β-thalassemia (Hb S-β-thal) in 138 (34.8%) and 11 (2.8%) Hb S/Hb D-Punjab (HBB: c.364G>C). Hb F ranged from 1.0 to 55.0%, with a mean of 21.2 ± 9.8%. The most common presentation was vaso-occlusive crises (VOCs), with 230 (54.8%) having had at least one prior to the study with 54 (13.2%) and 74 (18.9%) having between 2-3 and >3 VOCs, respectively. Hydroxyurea (HU) was prescribed to 157 (39.6%) patients. The most common complication was gallstones in 131 (33.1%), followed by acute splenic sequestration in 26.8% and avascular necrosis of the femoral head in 21.2% patients, respectively. Stroke, priapism and leg ulcers were rare. Gallstones, splenic sequestration and osteonecrosis were significantly more common in patients aged >16 years. Patients with Hb S-β-thal were similar to those with Hb SS in their clinical profiles. The phenotypic expression of sickle cell disease in Kuwaitis is unique in many respects. The role(s) of Hb F and other genetic modifiers require further elucidation.

Use of primaquine and glucose-6-phosphate dehydrogenase deficiency testing: Divergent policies and practices in malaria endemic countries

Primaquine is the only available antimalarial drug that kills dormant liver stages of Plasmodium vivax and Plasmodium ovale malarias and therefore prevents their relapse (‘radical cure’). It is also the only generally available antimalarial that rapidly sterilises mature P. falciparum gametocytes. Radical cure requires extended courses of primaquine (usually 14 days; total dose 3.5–7 mg/kg), whereas transmissibility reduction in falciparum malaria requires a single dose (formerly 0.75 mg/kg, now a single low dose [SLD] of 0.25 mg/kg is recommended). The main adverse effect of primaquine is dose-dependent haemolysis in glucose 6-phosphate dehydrogenase (G6PD) deficiency, the most common human enzymopathy. X-linked mutations conferring varying degrees of G6PD deficiency are prevalent throughout malaria-endemic regions. Phenotypic screening tests usually detect <30% of normal G6PD activity, identifying nearly all male hemizygotes and female homozygotes and some heterozygotes. Unfortunately, G6PD deficiency screening is usually unavailable at point of care, and, as a consequence, radical cure is greatly underused. Both haemolytic risk (determined by the prevalence and severity of G6PD deficiency polymorphisms) and relapse rates vary, so there has been considerable uncertainty in both policies and practices related to G6PD deficiency testing and use of primaquine for radical cure. Review of available information on the prevalence and severity of G6PD variants together with countries’ policies for the use of primaquine and G6PD deficiency testing confirms a wide range of practices. There remains lack of consensus on the requirement for G6PD deficiency testing before prescribing primaquine radical cure regimens. Despite substantially lower haemolytic risks, implementation of SLD primaquine as a P. falciparum gametocytocide also varies. In Africa, a few countries have recently adopted SLD primaquine, yet many with areas of low seasonal transmission do not use primaquine as an antimalarial at all. Most countries that recommended the higher 0.75 mg/kg single primaquine dose for falciparum malaria (e.g., most countries in the Americas) have not changed their recommendation. Some vivax malaria–endemic countries where G6PD deficiency testing is generally unavailable have adopted the once-weekly radical cure regimen (0.75 mg/kg/week for 8 weeks), known to be safer in less severe G6PD deficiency variants. There is substantial room for improvement in radical cure policies and practices.

Transfusion in Haemoglobinopathies: Review and recommendations for local blood banks and transfusion services in Oman

Sickle cell disease and homozygous β-thalassaemia are common haemoglobinopathies in Oman, with many implications for local healthcare services. The transfusions of such patients take place in many hospitals throughout the country. Indications for blood transfusions require local recommendations and guidelines to ensure standardised levels of care. This article summarises existing transfusion guidelines for this group of patients and provides recommendations for blood banks and transfusion services in Oman. This information is especially pertinent to medical professionals and policy-makers developing required services for the standardised transfusion support of these patients.

The super sickling haemoglobin HbS-Oman: a study of red cell sickling, K+ permeability and associations with disease severity in patients heterozygous for HbA and HbS-Oman (HbA/S-Oman genotype)

Studying different sickle cell genotypes may throw light on the pathogenesis of sickle cell disease (SCD). Here, the clinical profile, red cell sickling and K⁺ permeability in 29 SCD patients (15 patients with severe disease and 14 with a milder form) of HbA/S-Oman genotype were analysed. The super sickling nature of this Hb variant was confirmed. The red cell membrane permeability to K⁺ was markedly abnormal with elevated activities of P_sickle , Gardos channel and KCl cotransporter (KCC). Results were consistent with Ca²⁺ entry and Mg²⁺ loss via P_sickle stimulating Gardos channel and KCC activities. The abnormal red cell behaviour was similar to that in the commonest genotype of SCD, HbSS, in which the level of mutated Hb is considerably higher. Although activities of all three K⁺ transporters also correlated with the level of HbS-Oman, there was no association between transport phenotype and disease severity. The super sickling behaviour of HbS-Oman may obviate the need for solute loss and red cell dehydration to encourage Hb polymerisation, required in other SCD genotypes. Disease severity was reduced by concurrent α thalassaemia, as observed in other SCD genotypes, and represents an obvious genetic marker for prognostic tests of severity in young SCD patients of the HbA/S-Oman genotype.

The Sickle β-Thalassemia Phenotype

Sβ-thalassemia (Sβ-thal) is common among Gulf Arab patients with sickle cell disease, but the phenotype of this group had not been well-documented. We have studied a group of Kuwaiti patients and compared the phenotype in the homozygotes (SS) and Sβ-thal patients. Complete blood count, hemoglobin quantitation, serum bilirubin, and lactate dehydrogenase were determined with standard techniques. The patients were screened for α-globin genotype. The Sβ-thal patients were also screened for the HBG2 Xmn-1 polymorphism. β-Thal mutations were determined by arrayed primer extension or direct sequencing. There were 70 SS and 32 Sβ-thal patients with mean ages of 14.8±5.9 and 14.2±5.9 years, respectively. The Sβ-thal patients had more frequent, severe pain episodes per year compared with the SS, while the patterns among Sβ-thal and Sβ-thal patients were not significantly different. There were no differences in the frequencies of acute chest syndrome, gallstones, and blood transfusion in the SS and Sβ-thal patients. However, none of the Sβ-thal patients had been transfused. Among the Sβ-thal patients, 25 had β-thal and 7 had β-thal mutations, the most common being cd39 (C→T) and IVS-I-110 (G→A), respectively. Sβ-thal shows a severe phenotype in Kuwait, even among those with Sβ-thal, in whom the IVS-I-110 (G→A) mutation is predominant.

Red cell parameters in infant and children from the Arabian Peninsula

α+-Thalassemia trait and iron deficiency anemia are frequent causes of microcytosis and a common diagnostic challenge in Arabian children. In this study, their prevalences and effects on the red cell parameters were evaluated in 28,457 children aged one day to 6 years. α+-Thalassemia trait was considered to be present when mean cell volume (MCV) was <94 fL at birth and iron deficiency anemia when red cell distribution width (RDW) was >14.5%. The prevalence of α+-thalassemia trait was 15.7% (502/3,191), which was similar to previously reported values for adults (9-14%). Iron deficiency anemia peaked at 7 months (53%) and then declined at a rate of 8% per year. The nadirs of red blood cell count (RBC) and hemoglobin concentration (Hb) occurred at two months of age (physiological anemia). Subsequently, Hb increased at a rate similar to that of MCV, demonstrating the two processes are coupled. The third percentile MCV in children older than 3 months was ≤64 fL, which was significantly lower than that in European children. The third percentile Hb, on the other hand, was similar to that in European children. Thus, α+-thalassemia trait and iron deficiency anemia are exceptionally frequent in Arabian children and their red cell indices are considerably different from European-based norms. Careful interpretation of red cell parameters is required for the evaluation of microcytic anemia in Arabian children.

An awareness-raising E-learning approach for children living in a high diabetic population

Recent epidemiological studies have shown an increased incidence of diabetes worldwide. In United Arab Emirates (UAE), where this study on Emirati children was conducted, over 20% of the population has diabetes. With such a high incidence, there is a need to raise the awareness of the disease in order to reduce the growing number of cases and manage the disease more effectively. This research aims to identify the needs of affected children and proposes a design for an E-learning prototype that can pedagogically raise their awareness and knowledge of the disease. The use of a prototype was chosen in order to validate and refine the usability of the system, and to quickly evaluate user-interface designs without the need for an expensive working model to help refine and develop the system design. The system requirements were identified through a set of interviews with kindergarten teachers, curriculum design experts in UAE, and diabetes nutrition specialists and clinicians. The rationale behind the interview was to identify the optimal age group, describe the appropriate level of the instructional materials and activities, and propose a suitable learning approach that could facilitate and improve diabetes awareness among this age group. The prototype was evaluated by children, teachers, parents (or guardians) and nutrition specialists. We followed a three-stage software development based on a user-informed approach model for stepwise refinement that ranged from prototype to final design. The evaluation results indicate that the proposed computer-supported learning approach can generate positive learning and behavior in children while reducing the time needed to complete awareness tasks when compared to traditional methods; thus making learning more engaging and allowing children to learn at their own pace.

Subclinical reduced G6PD activity in rheumatoid arthritis and Sjögren's Syndrome patients: relation to clinical characteristics, disease activity and metabolic syndrome

OBJECTIVE

Glucose-6-phosphate dehydrogenase (G6PD) is an important site of metabolic control in the pentose phosphate pathway. The purpose of this study was to investigate the enzyme activity of G6PD in Rheumatoid Arthritis (RA) and Sjögren's Syndrome (SS) patients not known to be deficient in this enzyme. It was also within the scope of the aim to find the relation of G6PD to the presence of metabolic syndrome (MetS) in these patients.

METHODS

Erythrocyte G6PD activity was evaluated in 40 RA patients, 30 SS patients and in 30 age- and sex-matched control. The clinical characteristics, disease activity score (DAS28), SS disease activity (SSDAI) and damage (SSDDI) indices and presence of MetS of the included patients were analyzed in relation to the enzyme level.

RESULTS

The G6PD activity in RA patients (7.72 ± 3.57 U/g Hb) was significantly reduced compared to that in the SS patients (11.55 ± 3.14 U/g Hb) and control (13.23 ± 3.34 U/g Hb) especially those with MetS (4.61 ± 1.84 U/g Hb) (p < 0.001). There was a significant negative correlation of the G6PD activity with the disease duration and DAS28 (p < 0.001).

CONCLUSION

The results of this study, suggest that G6PD not only does not protect against MetS in RA, but may even be considered a risk factor for the development of this disorder. The identification of regulatory tools for G6PD activity may prove promising for treating the associated metabolic disorders and chronic inflammation in RA.

Regional consensus opinion for the management of Beta thalassemia major in the Arabian Gulf area

Thalassemia syndrome has diverse clinical presentations and a global spread that has far exceeded the classical Mediterranean basin where the mutations arose. The mutations that give rise to either alpha or beta thalassemia are numerous, resulting in a wide spectrum of clinical severity ranging from carrier state to life-threatening, inherited hemolytic anemia that requires regular blood transfusion. Beta thalassemia major constitutes a remarkable challenge to health care providers. The complications arising due to the anemia, transfusional iron overload, as well as other therapy-related complications add to the complexity of this condition. To produce this consensus opinion manuscript, a PubMed search was performed to gather evidence-based original articles, review articles, as well as published work reflecting the experience of physicians and scientists in the Arabian Gulf region in an effort to standardize the management protocol.

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.

Prevalence of high blood pressure, heart disease, thalassemia, sickle-cell anemia, and iron-deficiency anemia among the UAE adolescent population

This study examined the prevalence of high blood pressure, heart disease, and medical diagnoses in relation to blood disorders, among 6,329 adolescent students (age 15 to 18 years) who reside in the United Arab Emirates (UAE). Findings indicated that the overall prevalence of high blood pressure and heart disease was 1.8% and 1.3%, respectively. Overall, the prevalence for thalassemia, sickle-cell anemia, and iron-deficiency anemia was 0.9%, 1.6%, and 5%, respectively. Bivariate analysis revealed statistically significant differences in the prevalence of high blood pressure among the local and expatriate adolescent population in the Emirate of Sharjah. Similarly, statistically significant differences in the prevalence of iron-deficiency anemia were observed among the local and expatriate population in Abu Dhabi city, the western region of Abu Dhabi, and Al-Ain. Multivariate analysis revealed the following significant predictors of high blood pressure: residing in proximity to industry, nonconventional substance abuse, and age when smoking or exposure to smoking began. Ethnicity was a significant predictor of heart disease, thalassemia, sickle-cell anemia, and iron-deficiency anemia. In addition, predictors of thalassemia included gender (female) and participating in physical activity. Participants diagnosed with sickle-cell anemia and iron-deficiency anemia were more likely to experience different physical activities.

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.

Glucose-6-Phosphate Dehydrogenase Deficiency among Male Blood Donors in Sana'a City, Yemen

OBJECTIVES

To determine the prevalence of Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency among Yemeni people from different regions of the country living in the capital city, Sana'a, giving an indication of its overall prevalence in Yemen.

METHODS

A cross-sectional study was conducted among Yemeni male blood donors attending the Department of Blood Bank at the National Centre of the Public Health Laboratories in the capital city, Sana'a, Yemen. Fluorescent spot method was used for screening, spectrophotometeric estimation of G-6-PD activity and separation by electrophoresis was done to determine the G-6-PD phenotype.

RESULTS

Of the total 508 male blood donors recruited into the study, 36 were G-6-PD deficient, giving a likely G-6-PD deficiency prevalence of 7.1%. None of these deficient donors had history of anemia or jaundice. Thirty-five of these deficient cases (97.2%) showed severe G-6-PD deficiency class II (<10% of normal activity), and their phenotyping presumptively revealed a G-6-PD-Mediterranean variant.

CONCLUSION

The results showed a significant presence of G-6-PD deficiency with predominance of a severe G-6-PD deficiency type in these blood donors in Sana'a City, which could represent an important health problem through occurrence of hemolytic anemia under oxidative stress. A larger sample size is needed to determine the overall prevalence of G-6-PD deficiency, and should be extended to include DNA analysis to identify its variants in Yemen.

Sickle cell disease in Middle East Arab countries

The sickle cell (HbS) gene occurs at a variable frequency in the Middle Eastern Arab countries, with characteristic distribution patterns and representing an overall picture of blood genetic disorders in the region. The origin of the gene has been debated, but studies using β-globin gene haplotypes have ascertained that there were multiple origins for HbS. In some regions the HbS gene is common and exhibits polymorphism, while the reverse is true in others. A common causative factor for the high prevalence and maintenance of HbS and thalassaemia genes is malaria endemicity. The HbS gene also co-exists with other haemoglobin variants and thalassaemia genes and the resulting clinical state is referred to as sickle cell disease (SCD). In the Middle Eastern Arab countries, the clinical picture of SCD expresses two distinct forms, the benign and the severe forms, which are related to two distinct β-globin gene haplotypes. These are referred to as the Saudi-Indian and the Benin haplotypes, respectively. In a majority of the Middle Eastern Arab countries the HbS is linked to the Saudi-Indian haplotype, while in others it is linked to the Benin haplotype. This review outlines the frequency, distribution, clinical feature, management and prevention as well as gene interactions of the HbS genes with other haemoglobin disorders in the Middle Eastern Arab countries.

Molecular characterization of glucose-6-phosphate dehydrogenase deficient variants in Baghdad city - Iraq

BACKGROUND

Although G6PD deficiency is the most common genetically determined blood disorder among Iraqis, its molecular basis has only recently been studied among the Kurds in North Iraq, while studies focusing on Arabs in other parts of Iraq are still absent.

METHODS

A total of 1810 apparently healthy adult male blood donors were randomly recruited from the national blood transfusion center in Baghdad. They were classified into G6PD deficient and non-deficient individuals based on the results of methemoglobin reduction test (MHRT), with confirmation of deficiency by subsequent enzyme assays. DNA from deficient individuals was studied using a polymerase chain reaction-Restriction fragment length polymorphism (PCR-RFLP) for four deficient molecular variants, namely G6PD Mediterranean (563 C→T), Chatham (1003 G→A), A- (202 G→A) and Aures (143 T→C). A subset of those with the Mediterranean variant, were further investigated for the 1311 (C→T) silent mutation.

RESULTS

G6PD deficiency was detected in 109 of the 1810 screened male individuals (6.0%). Among 101 G6PD deficient males molecularly studied, the Mediterranean mutation was detected in 75 cases (74.3%), G6PD Chatham in 5 cases (5.0%), G6PD A- in two cases (2.0%), and G6PD Aures in none. The 1311 silent mutation was detected in 48 out of the 51 G6PD deficient males with the Mediterranean variant studied (94.1%).

CONCLUSIONS

Three polymorphic variants namely: the Mediterranean, Chatham and A-, constituted more than 80% of G6PD deficient variants among males in Baghdad. Iraq. This observation is to some extent comparable to other Asian Arab countries, neighboring Turkey and Iran.

Molecular basis of β-thalassemia in the United Arab Emirates

In an attempt to define the prevalence of β-thalassemia (β-thal) in the United Arab Emirates (UAE), we have conducted molecular studies on nearly 2000 randomly-selected adult UAE nationals. The results demonstrated that the prevalence of β-globin gene defects in the UAE was 8.5%. Among these anomalies were β-thal mutations, abnormal hemoglobin (Hb) variants, e.g., Hb S, Hb D-Punjab, Hb O-Arab, Hb C and Hb E. The sickle gene (β(S) or Hb S) contributed significantly to the molecular epidemiology of the hemoglobinopathies in the UAE. In this article, Hb S and other abnormal Hbs are excluded as they are comprehensively described by other contributors in this current issue. The molecular characterization and mutational analyses of all β-thal patients were carried out using current molecular techniques including amplification refractory mutation system (ARMS), restriction enzyme analysis (REA), dot-blot hybridization, β-strip hybridization, allele-specific oligonucleotide (ASO), polymerase chain reaction (PCR), gap-PCR and DNA Sequencing. Most of these techniques are now virtually obsolete. Almost all molecular characterizations are currently performed through PCR followed by DNA sequencing using a fully automated ABI PRISM™ 3130 Genetic Analyzer. Our molecular studies showed that the majority of the β-thal mutations in the UAE are very severe; the most common allele was the IVS-I-5 (G>C). Although this allele is a β(+)-thal, its phenotype is very severe. All other mutations are also severe β(0)-thal. High frequency of moderate or severe β-thal mutations have implications in the wide spectrum of clinical manifestations seen in patients whose phenotypes vary from β-thal intermedia (β-TI) to severe transfusion-dependent β-thal major (β-TM). The molecular pathology of the β-thal patients demonstrated that a vast majority were homozygous. The most frequent homozygous mutation was the IVS-I-5(G>C)/IVS-I-5(G>C) (53.0%) followed by -25 bp del/-25 bp del (6.8%), codons 8/9(+G)/codons 8/9(+G) (2.8%) and codon 39(C>T)/codon 39(C>T) (2.4%). Four mutations accounted for 65.0% of the homozygous patient population. Remarkably, the two most prevalent mutations, IVS-I-5 and Hb S, accounted for 77% of all the homozygous β-thal patients from the UAE. We showed 13 discrete homozygosities in the UAE national patients in contrast to 23 homozygosities in the expatriate population. Since the number of homozygous mutations has a direct correlation with the degree of consanguinity, the data shown here corroborate the social tendency towards family planning. In fact, in the UAE, more than 50% of all marriages are between relatives and more than half of these are between first cousins.

Neonatal Screening: Mean haemoglobin and red cell indices in cord blood from Omani neonates

OBJECTIVES

The aim of this study was to validate the interpretation of red blood cell indices in complete blood count (CBC) and high performance liquid chromatography (HPLC) results on cord blood samples in consecutive Omani neonates.

METHODS

Cord blood samples from 7,837 neonates, were analysed with CBC and HPLC using the β-thalassaemia short programme. Direct sequencing of abnormal samples with HbS, HbD, HbE and HbC was performed to validate the HPLC results. Additionally, in cases with HbA β10%, the β-globin gene was directly sequenced for β-thalassaemia mutation analysis.

RESULTS

Overall, 4,042 subjects (51.58%) had normal HPLC (HbA 22.88±8.03; HbF 77.02±8.04), whereas the presence of Hb Barts in the remaining 3,795 cases (48.42%) indicated the presence of α-thalassaemia. No case of HbH was detected. In the former subgroup respectively, the mean Hb (15.38±2.04 g/dl) red blood cell (RBC) count (4.69±0.68 × 10(12)/l), Hct (50.5±7.18%), mean corpuscular volume (MCV) (107.66±7.75 fl), mean corpuscular haemoglobin (MCH) (33.31±4.07 pg), mean corpuscular haemoglobin concentration (MCHC) (30.98±3.44 g/dl), red cell distribution width (RDW) (17.01±2.17%) whereas, in the latter group with α-thalassaemia, it was (14.79±2.90 g/dl); (5.09±0.77 × 10(12)/l); (49.7±7.40%); (97.29±13.8 fl); (29.74±11.80 pg); (30.39±3.6 g/dl), and (18.09±2.56%) respectively. DNA sequencing of samples with abnormal haemoglobin could validate the CBC and HLPC interpretations in all cases.

CONCLUSION

This is the first study comparing the hemoglobin and red cell indices in the cord blood from newborn Omani subjects with those from other countries in the region, showing comparable results to those seen in Saudi neonates. The study also validates the CBC and HPLC interpretations of the cord blood red cell indices in the Omani neonate. The incidence of α-thalassaemia diagnosed by the presence of Hb Barts in cord blood of neonates was 48.42%.

Molecular Characterization of Cosenza Mutation among Patients with Glucose-6-Phosphate Dehydrogenase Deficiency in huzestan Province, Southwest Iran

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common hereditary enzymatic disorders in human, increases the vulnerability of erythrocytes to oxidative stress. It is also characterized by remarkable molecular and biochemical heterogeneity. According to previous investigations, G6PD Cosenza (G1376C) is a common G6PD mutation in some parts of . Therefore in the present study we have characterized mutation among G6PD deficient individuals in Khuzestan province. In order to identify G6PD Cosenza, we analyzed the G6PD gene in 64 samples out of 231 deficient individuals who had not G6PD Mediterranean mutation, using PCR- restriction fragment length polymorphism (RFLP) method. G6PD Cosenza mutation was found in 6 males of 231 samples, resulting in the relative rate of 2.6% and allele frequency of 0.023 among Khuzestanian G6PD deficient subjects. A comparison of these results with previous findings in some parts of suggests that G6PD Cosenza is a common mutation in Khuzestanian G6PD deficient individuals.

Erythrocyte reference values in Emirati people with and without α+ thalassemia

BACKGROUND

Interpreting the erythroid lineage in populations with high frequency of α+ thalassemia allele is challenging due to the high prevalence of α+ thalassemia homozygotes. For such populations, separate reference values for normal and α+ thalassemia homozygotes are needed.

METHODS

We studied the erythroid lineage in 1,079 citizens of United Arab Emirates (UAE). Subjects with abnormal hemoglobin (39), iron deficiency (136) or erroneous entries (8) were excluded. MCV distribution in the remaining individuals (896) was visibly bimodal. Statistical mixture analysis with Normix program was used to separate subpopulations with normal and small red cells. Hardy-Weinberg equation was used to estimate genotype frequencies.

RESULTS

MCV of 78.0 fl separated phenotype-derived normal homozygotes (715) from phenotype-derived α+ thalassemia homozygotes (181). The erythrocyte indices were significantly different between the two groups (p < 0.0001). The overall prevalence of phenotype-derived α+ thalassemia homozygotes (-α/-α) was 0.20 and markedly varied among tribes, 0 to 0.31 (Mean = 0.15). The frequency of phenotype-derived α+ thalassemia allele was 0.44; when accounting for tribal population structure and inbreeding, the calculated frequency was 0.34. These values were very similar to those found in the same population by genotyping and other phenotyping methods. The erythrocyte reference values for phenotype-derived normal homozygotes in Emiratis closely overlapped with those for Caucasians and normal homozygotes defined by genotyping. The reference values for phenotype-derived α+ thalassemia homozygotes in Emiratis also closely overlapped with those for α+ thalassemia homozygotes defined by genotyping.

CONCLUSION

In populations with frequent α+ thalassemia mutations, two sets of erythrocyte reference values could be determined without genotyping.

Thalassemia trait in outpatient clinics of Sana'a City, Yemen

Blood samples were collected from 699 patients attending out patient clinics in Sana'a City, Yemen, to obtain some idea of the prevalence of the thalassemias in our country. Complete blood count, hemoglobin (Hb) electrophoresis, quantitation of Hb A(2) and Hb F, and serum ferritin were determined. Microcytic, hypochromic red cells were found in 103 subjects (14.7%). Iron deficiency alone accounted for only a small proportion of these (n = 12), whereas features suggestive of beta-thalassemia (beta-thal) were present in 31 patients (4.43%) and features suggestive of alpha-thal trait were found in 60 patients (8.6%). The study showed that thalassemia probably accounts for most red cell microcytosis in these out patient clinics, and could represent a significant health problem through births of homozygotes and compound heterozygotes with severe disorders. This pilot study should be repeated with improved technology, and extended to include globin gene analysis to define the nature of the disorders that remain poorly diagnosed.

Haemoglobinopathies encountered at Khoula Hospital, Oman: A retrospective study

OBJECTIVE

The objective of this study was to find out the frequency of abnormal haemoglobins (Hb) in patients referred to Khoula Hospital, Oman and compare the data from other studies by assessing a large number of patients.

METHODS

The results of 27,403 patients, either admitted to Khoula Hospital or referred to it from different health centres during the 4 years of the study from January 2001 till December 2004, were analysed for haemoglobinopathies. The laboratory methods used for detection of abnormal haemoglobins were sickle cell solubility test and haemoglobin electrophoresis.

RESULTS

The frequency of sickle cell trait was 7.5%, sickle cell disease 0.46% and other Hb variants were 0.102%. The results correlate well with that of the National Genetic Blood Disorder Survey carried out by the research and studies department, Ministry of Health, Sultanate of Oman, during a 4 year period from January 2001 till December 2004.

CONCLUSION

This retrospective study demonstrates the high prevalence of haemoglobinopathies among the studied group of patients. More attention to the importance of health education and genetic counselling is required for the prevention of this public health problem in the country.

Molecular characterization of erythrocyte glucose-6-phosphate dehydrogenase deficiency in Tunisia

Screening of G6PD deficiency was carried out on 79 unrelated subjects (32 females and 47 males), all coming from out consultation. DNA from deficient subject (11 females and 30 males) was analyzed for the presence of G6PD mutation. Known mutations were studied by the appropriate restriction enzyme digestion of fragment amplified by PCR. Where the mutation could not be identified in this way, the samples were subjected to SSCP analysis and abnormal fragments were sequenced. Through these methods, seven different mutations have been identified. Among deficient females, eight had the African variant A-(tow of them were homozygous) and three had the Mediterranean variant, one of them was homozygous and have had a haemolytic crisis after ingestion of fava beans showing at birth manifestation of neonatal jaundice. Among deficient males, four were hospitalized and transfused after a haemolytic crisis due to ingestion of fava beans. All of them have had manifestation of neonatal jaundice. Of them, one carried the Mediterranean variant and three others had the African variant A-. Among the remaining deficient males, 15 had A-variant, two had the Aurès mutation. SSCP analysis of nine mild deficient males, revealed the presence of the association of 1311 CT/93 TC in two subjects, a newly described silent mutation in the exon 12 associated with the polymorphism in the intron 11 93 TC in one subject and tow single intronic base deletion. The first is IVS V 17 (-C) found in two subjects and the second is IVS VIII 43 (-G) encountered in four subjects.

Sickle cell disease and pregnancy in Bahrain

OBJECTIVE

To determine the morbidity and outcome of pregnancies complicated by homozygous sickle cell disease (SCD) in Bahrain.

METHODS

A controlled study was conducted of all the pregnancies of women with SCD who were delivered at Salmaniya Medical Complex and affiliate hospitals in Bahrain between January 1, 1998, and December 31, 2002.

RESULTS

There were 351 pregnancies with SCD, giving an incidence of 0.67%. The mean+/-S.D. age of women with SCD was 28.8+/-5.7 years. These women, who were mostly from Shia villages, had more spontaneous abortions than the 351 controls (32% and 12%, respectively). Compared with the control group, the mean+/-S.D. number of pregnancies among women with SCD was 5.0+/-1.9 vs. 5.7+/-3.1; birth weight, 2,965+/-540 g vs. 3,457+/-497 g; rate of preterm deliveries, 25.9% vs. 12%; incidence of intrauterine growth restriction, 10% to 13% vs. 4% to 7%; Apgar scores at 1 and 10 min, 8.1+/-0.8 and 8.8+/-0.8; and cesarean section rate, 19.0% vs. 12.7%. There were no differences in the rates of pre-eclampsia, antepartum and postpartum hemorrhage, or stillbirth. There were 4 maternal deaths directly related to SCD complications. Hemoglobin analysis was performed in 86% of the women with SCD. Of these women, 60.6% had homozygous SCD with raised levels of fetal hemoglobin (more than 5% HbF); 9.6% had sickle cell hemoglobin with beta-thalassemia disease; and 1.4% had sickle cell hemoglobin only. Vaso-occlusive crises were the most common cause of hospital admissions during pregnancy (42.2%), while hemolytic and sequestration crises accounted for 28.0% and 0.6% of admissions.

CONCLUSION

Mortality, morbidity, and perinatal loss are still considerable among women with SCD in Bahrain. To reduce mortality and morbidity, there is a need for a multidisciplinary team able to deal with pregnancy complications due to SCD.

United Arab Emirates: communities and community genetics

The UAE society is cosmopolitan, but the indigenous inhabitants are traditional with puritanical values despite their exposure to other vastly different cultures and habits. Marriages between consanguineous couples are still the norm rather than the exception. As a result, there is a high frequency of genetic disorders, particularly autosomal recessive types. Despite the high frequency of genetic disorders like haemoglobinopathies and others characteristically found in this population, genetic services are inadequate. Screening for certain disorders like thalassaemia are not applied on a wide scale. Abortion is illegal, and therefore, prenatal diagnosis or preconception tests are not done. With the absence of a good national database, deficiency of genetic services and absence of preventative alternatives for carrier couples, genetic counsellors find it difficult to advice pragmatic solutions to issues relating to genetic diseases. This paper reviews common genetic problems in the UAE with special emphasis on available genetic services and support to families with children with inherited disorders. Existing barriers to the improvement of clinical services by prenatal counselling are also discussed.

Prevalence of the sickle cell gene in Yemen: a pilot study

To determine the prevalence of the sickle cell gene (betaS) in Yemen and amongst people from different regions of the country living in the capital, Sana'a City, cord blood samples from 1,500 consenting mothers were collected from hospitals in Sana'a City between July and December 2001. The names and original homes of the parents were recorded. Cation exchange high performance liquid chromatography (HPLC) analysis was used for screening, while isoelectric focusing (IEF) and DNA polymerase chain reaction (PCR) were used to confirm Hb S [beta6(A3)Glu-->Val]. Thirty-three samples were found to show Hb FAS, giving an overall likely betaS gene frequency of 0.011. The betaS gene frequency varied with the part of the country from which the parents came. Amongst people from Taiz and Haja in the west, the gene frequency was more than 0.04, but less than 0.004 amongst people from Ibb, adjacent to the governorate (administrative division) of Taiz. Of 66 chromosomes from babies carrying the betaS gene, only 1.5% also carried the -158 (C-->T) Ggamma-globin gene XmnI site compared with 16.1% of 168 chromosomes from babies without the betaS gene from the same regions. The results of this study show a higher betaS gene frequency in the western coastal part of Yemen than in the central mountainous and eastern desert areas. The incidence of affected homozygous births may therefore reach 20/10,000 in certain areas, although it is much lower than this overall. Limited health resources can best be invested in developing a program of education, screening and health care, initially prioritizing those communities residing in the western areas of Yemen with the highest betaS gene frequency.

β-Thalassemia major and its effect on amino acid metabolism and growth in patients in the United Arab Emirates

BACKGROUND

There may be a marked reduction in essential amino acids in the serum of children with thalassemia major and this is related to decreased growth in affected children.

METHODS

One hundred patients with beta-thalassemia and 50 control children selected from among those who had presented with minor disorders unrelated to hematological disease were recruited. Urine and heparinized blood were collected from fasting thalassemic patients. After deproteinization and dilution, amino acid concentrations were measured using ion-exchange chromatography.

RESULTS

Isoleucine (p<0.0001), phenylalanine (p<0.05), tyrosine (p<0.0001), taurine (p<0.0001) and glutamine (p<0.01) were significantly decreased in the plasma of thalassemic patients compared to the control group. Whereas glutamate (p<0.0001), serine (p<0.05) and proline (p<0.05) were significantly higher in thalassemic patients, threonine, glycine, alanine, valine, methionine, leucine, ornithine, lysine, histidine and arginine values were not different. The essential amino acids taurine (p<0.0001), methionine (p<0.01), valine (p<0.01), phenylalanine (p<0.01) and leucine (p<0.05) were significantly decreased in urine of thalassemic patients vs. controls, but threonine and ornithine were not different. The mean urinary excretion rate of beta-aminoisobutyric acid was not different (69+/-96 in thalassemics vs. 41+/-52 in controls). However, most plasma and urinary essential amino acids were found to be lower in thalassemics. Thalassemic patients were also found to be significantly growth impaired for age, both in height and weight compared to controls.

CONCLUSION

Lower plasma values of essential amino acids and a decrease in urinary amino acids occur in thalassemic patients. Growth impairment both in height and weight also occurs in thalassemic patients compared to a control population.

Alpha-2-globin gene polyadenylation (AATAAA-->AATAAG) mutation in hemoglobin H disease among Kuwaitis

OBJECTIVES

In the Arabian Gulf region, hemoglobin (Hb) H disease usually results from homozygosity or compound heterozygosity involving the alpha2-globin gene polyadenylation (poly A) signal (AATAAA-->AATAAG) mutation (alpha(T)alpha). Here we document the clinical and hemato logical characteristics of children with Hb H disease being followed in Kuwait.

SUBJECTS AND METHODS

Twenty-four patients (0.5-12 years old, mean 4.7 +/- 3.5 years) with persistent microcytic, hypochromic anemia (and normal iron status as well as normal Hb A2 levels) were referred to the pediatric hematology clinic for further investigations. They were all screened for the alpha+-thalassemia (alpha+-thal; -3.7 kb) deletion using a standard PCR method. They were also screened for the alpha2-globin gene alpha(T)alpha allele and the 5nt deletion (-alpha5nt) in the first intervening sequence, which are common alpha-thal alleles in this population. They were followed up for periods ranging from 2 to 8 years.

RESULTS

Of the 24 patients, 4 (16.7%) also had sickle cell trait (Hb-AS), while 7 (29.2%) were glucose-6-phosphate dehydrogenase deficient. Only 1 patient had significant hepatosplenomegaly and 1 developed gallstones. While none was on chronic transfusion therapy, 8 (33.3%) had been transfused at least once and, in 3 instances, this was secondary to parvovirus B19 +ve aplastic crisis. The alpha-globin genotype was successfully determined in almost all patients. The results showed that 17 (70.8%) patients were homozygous for the poly A mutation (alpha(T)alpha/alpha(T)alpha), 6 (25.0%) were compound heterozygotes for this and the alpha+-thal (-3.7 kb) deletion (-alpha/alpha(T)alpha) and 1 (4.2%) was undetermined. There were no significant differences in the phenotypes of the 2 genotypes and their hematological features were identical.

CONCLUSIONS

Hb H disease involving the poly A mutation is a mild thal intermedia phenotype among Kuwaitis. There are no serious complications and there is no need for regular blood transfusion.

RBC alloimmunization and autoimmunization among transfusion-dependent Arab thalassemia patients

BACKGROUND

Thalassemia major is a common hemoglobinopathy in the Arabian Gulf region. However, limited data are available on the frequency of RBC alloimmunization and autoimmunization in transfusion-dependent Arab thalassemia patients.

STUDY DESIGN AND METHODS

A total of 190 thalassemia major patients were classified as Kuwaiti Arab and non-Kuwaiti Arab. Pretransfusion investigation records were reviewed for the presence of RBC alloantibody and autoantibody, and the age at which RBC alloantibody was developed.

RESULTS

Fifty-seven (30%) patients developed RBC alloantibodies. The most common clinically significant alloantibodies were directed against antigens in the Kell and Rh systems. Anti-K developed in 41 (72%) patients followed by anti-E in 26 (45.6%). RBC autoantibodies developed in 21 (11%) patients with and without underlying RBC alloantibodies. Sixty-six (49.6%) RBC alloantibodies developed between the ages of 2 and 10 years.

CONCLUSION

Several factors might have contributed to the high alloimmunization and autoimmunization rate observed in this study, including the heterogeneity of the population living in Kuwait, lack of better-matched donors for those patients, and the use of poststorage leukodepleted blood. It is recommended that thalassemia patients receive blood matched for Rh and Kell antigens and prestorage leukodepleted RBCs.

Genetic epidemiology of HbS in Oman: multicentric origin for the betaS gene

On the basis of a sample of 117 chromosomes, we have demonstrated the multicentric origin of the sickle mutation in Northern Oman. Three major haplotypes coexist: 52.1% Benin (typical and atypicals), 26.7% Arab-India, and 21.4% Bantu. These haplotypes are not autochthonous to Oman but originated elsewhere and arrived in Oman by gene flow. The distribution of haplotypes is in excellent agreement with the historical record, which establishes clear ancient contacts between Oman and sub-Sahara west Africa and explains the presence of the Benin haplotype; contacts with Iraq, Iran, present-day Pakistan, and India explain the presence of the Arab-India haplotype. More recent contacts with East Africa (Zanzibar/Mombasa) explain the presence of the Bantu haplotype. The pattern of the Arab-India haplotype in the populations of the Arabian peninsula reinforces the hypothesis that this particular mutation originated in the Harappa culture or in a nearby population and in addition reveals that the Sassanian Empire might have been the vehicle by which this Indo-European sickle mutation migrated (gene flow) to the present-day Arabian peninsula, including Oman.

Diversity in expression of glucose-6-phosphate dehydrogenase deficiency in females

The aims of this study were to determine the prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency in the United Arab Emirates (UAE), to describe the different mutations in the population, to determine its prevalence, and to study inheritance patterns in families of G6PD-deficient individuals. All infants born at Tawam Hospital, Al-Ain, UAE from January 1994 to September 1996 were screened at birth for their G6PD status. In addition, those attending well-baby clinics during the period were also screened for the disorder. Families of 40 known G6PD-deficient individuals, selected randomly from the records of three hospitals in the country, were assessed for G6PD deficiency. Where appropriate, this was followed by definition of G6PD mutations. Of 8198 infants, 746 (9.1%), comprising 15% of males and 5% of females tested, were found to be G6PD deficient. A total of 27 families were further assessed: of these, all but one family had the nt563 Mediterranean mutation. In one family, two individuals had the nt202 African mutation. The high manifestation of G6PD deficiency in women may be due to the preferential expression of the G6PD-deficient gene and X-inactivation of the normal gene, and/or to the presence of an 'enhancer' gene that makes the expression of the G6PD deficiency more likely. The high level of consanguinity which, theoretically, should result in a high proportion of homozygotes and consequently a higher proportion of females with the deficiency, was not found to be a significant factor.

A study of possible deleterious effects of consanguinity

The aim of the study was to determine whether consanguineous marriages result in reproductive wastage and an increased incidence of illness in the offspring in a community with a long history of inbreeding and an expected high rate of consanguineous marriage. A representative sample of 2200 women aged > or = 15 years from Dubai and Al Ain, two cities in the United Arab Emirates, representing on the one hand a modern metropolis and on the other a traditional society, were studied. A questionnaire, which included questions on age, parity, gravidity, number of stillbirths, number of abortions, number of children alive, neonatal deaths and specific illnesses in children, was administered by nurses in antenatal and gynaecological clinics in the two cities. The rate of consanguineous marriage was 50.5% and parity, gravidity, ages and number of children were similar in consanguineous and non-consanguineous groups. There was no significant difference in rates of abortion, stillbirth and neonatal death between the two groups. Overall, there was statistically significant higher reproductive wastage in consanguineous couples, but when the category of less than second cousins was excluded from the consanguineous group no difference was found in reproductive wastage between consanguineous and non-consanguineous marriages. Children born to consanguineous unions also had significantly higher incidences of illnesses (37.1%) than those of non-consanguineous unions (29%). The occurrence of malignancies, congenital abnormalities, mental retardation and physical handicap was significantly higher in offspring of consanguineous than non-consanguineous marriages. In conclusion, consanguinity did not result in reproductive wastage, but was found to be an important factor in the causation of specific illnesses in offspring.

The prevalence of hemoglobin S and glucose-6-phosphate dehydrogenase deficiency in Jordanian newborn

OBJECTIVE

The aim of this study was to determine the incidence of HbS and glucose-6-phosphate dehydrogenase (G6PD) deficiency in Jordanian newborn.

STUDY DESIGN

A total of 181 male and female babies born at Princess Basma Teaching Hospital, randomly selected, and cord blood samples were collected, and the erythrocyte G6PD activity was measured, and the hemoglobin electrophoresis for blood lysate was conducted and scanned for HbS scanning.

RESULTS

The frequencies of two major red cell genetic defects, sickle hemoglobin (HbS) and deficiency G6PD was determined, of the studied subjects 10 (11%) females and 11 (12%) males were found to be deficient in the G6PD gene. The frequency of HbS carriers among the females was 4% while it was 6% among males. The coincidence of both G6PD deficiency and sickle cell hemoglobin in the samples was 1%. No coincidence was found between G6PD deficiency and hyperbilirubinemia.

CONCLUSION

A better understanding of the distributions of these genetic disorders has the potential to aid in the more efficient utilization of health care resources and improved planning.

Splenomegaly in Arab children with idiopathic thrombocytopenic purpura

Splenomegaly was found in 31 (55%) of 56 Arab children with idiopathic thrombocytopenic purpura. Of those with splenomegaly, 84% had evidence of iron deficiency anemia compared to 48% in those without splenomegaly (P<0.001). There was no significant difference in the prevalence of ss-thalassemia trait or history of preceding viral infection between those with or without splenomegaly. This study demonstrates a much higher prevalence of splenomegaly in Arab children with idiopathic thrombocytopenic purpura, most probably related to associated iron deficiency.

The spectrum of beta thalassaemia mutations in the UAE national population

The beta thalassaemia alleles in 50 beta thalassaemia heterozygotes originating from many parts of the United Arab Emirates (UAE) have been characterised using the allele specific priming technique of the polymerase chain reaction (PCR). The IVSI-5 (G-->C) mutation was found to be present in 66%, while six other alleles occurred at the much lower frequencies of 2% to 8%. These were codon 8/9 (+G), IVSI-1, 3' end (-25 bp), codon 5 (-CT), IVSII-1 (G-->A), codon 30 (G-->C), and codon 15 (G-->A). The mutation types and percentages are compared with other Mediterranean Arab countries and neighbouring areas. It is proposed that IVSI-5 and other Asian Indian mutations were introduced into the UAE by population migration from the region previously known as Baluchistan. These findings should be useful for genetic counselling and the development of a first trimester prenatal diagnosis programme based on direct detection of mutations in the UAE.