Prenatal diagnosis of beta-thalassaemia and sickle cell anaemia in Turkey

A shared motif of hla-dpb1 affecting the susceptibility to pr3-anca positive granulomatosis with polyangiitis: comparative analysis of a Turkish cohort with matched healthy controls

We aimed to analyse the distribution of HLA Class 2 genotypes which were reported among the genetic risk factors for ANCA-associated vasculitis (AAV) among Turkish patients in comparison with healthy subjects and previously reported data of AAV cohorts. Ninety-eight patients (F/M: 47/51 and mean age: 49 ± 1.14) were enrolled in the study and records of gender and birthplace-matched 196 healthy kidney donors were used as the control group. Patients were classified according to the clinical subgroups and ANCA serotypes (MPO-AAV, PR3-AAV). DNA was isolated from venous blood from all patients, and high-resolution HLA Class 2 genotyping was carried out by using NGS-Omixon Holotype HLA Kit. The frequencies of HLA-DQB1*03:03, - *06:04, and -DPB1*13:01, -*16:01 and -*66:01:00 alleles were significantly higher, and the frequencies of HLA-DQB1*02:02, -DPB1*02:01 and -*04:01 alleles were lower in the PR3-AAV subgroup (n = 53) compared to the controls. Comparison of amino acid sequences of the associated HLA-DPB1 alleles revealed the sequence of D-E-A-V in risk alleles replaced with the G-G-P-M sequence in protective alleles between 84 and 87th positions. Structural analysis of the HLA-DPB1*02:01 showed that this shared position is in the contact area between HLA-DP α and β chains and within pocket 1 of the antigen-binding groove. First HLA genotyping analysis in Turkish AAV patients revealed a negative correlation between PR3-ANCA positivity and certain HLA-DPB1 alleles contradictory to the results reported from European cohorts. Known functional effects of D-E-A-V sequence on HLA-DPB1 support the importance of our finding, but further studies are needed to reveal its pathogenic mechanisms.

Investigation of molecular heterogeneity of β-thalassemia disorder in District Charsadda of Pakistan

Objective:

Thalassemia is blood related disease which arises from the reduced level of hemoglobin in red blood cells (RBC), a protein responsible for carrying oxygen inside the body. Considering its widespread occurrence in developing countries like Pakistan, this study aims to investigate the common molecular anomalies of the beta thalassemia disease in district Charsadda, Khyber Pakhtunkhwa.

Methods:

This work was done at Abdul Wali Khan University (AWKU) Mardan, Khyber Pakhtunkhwa, Pakistan. The work was performed on the blood samples collected from the patients and their families with beta thalassemia major (n = 13 families) belonged to District Charsadda. The collected blood samples were analyzed for presence of six known mutations with the help of polymerase cha in reaction technique i.e. amplification of refractory mutation system.

Results:

Our Study reports six known mutations (IVS-1-5, FSC 8/9, CD 41/42, IVS-1-1, CD 15 and FSC-5) accounting for about 90% of total beta thalassemia genes in this country. Among the reported mutations, IVS 1-5 was the most prevalent beta thalassemia gene in patients belonging to District Charsadda.

Conclusion:

The results and findings of the current study may help in accessing the frequency of these common mutations and in initiating pre-natal diagnosis programme in Pakistan.

Prenatal diagnosis of sickle cell disease by the technique of PCR

Sickle cell disease (SCD) is prevalent in Central India and causes major morbidity and mortality. There is a lack of prenatal diagnostic facility near population affected with SCD. This is the pilot study in our region with the aim to establish prenatal diagnostic facility for the couples carrying sickle cell gene in Central India, in order to help them take an informed decision regarding fetus affected with SCD and also to calculate sensitivity of polymerase chain reaction (PCR) technique in our set up with follow up high performance liquid chromatography (HPLC) of baby's blood sample. Fetal sampling was done by chorionic villous biopsy. Extracted DNA was subjected to amplification refractory mutation system (ARMS-PCR) to detect sickle cell mutation (GAG → GTG) in the sixth codon of β globin gene. Follow-up HPLC was done to detect baby's Hb pattern. Prenatal diagnosis of sickle cell anemia was offered in total 37 cases out of which one (2.7 %) fetal sample was inadequate. Total 26 (70.27 %) fetuses had AS Hb genotype, 3 (8.11 %) had AA Hb genotype and 3 (8.11 %) had SS Hb genotype while remaining 4 (10.81 %) were given AA/AS Hb genotype. All couples with SS fetuses opted for MTP. Follow up HPLC was performed in 24 cases, out of which 18 (75 %) were correlated and 6 (25 %) were mismatched. In present study sensitivity of ARMS-PCR was 75 %. ARMS-PCR is a simple technique to be established initially for providing rapid prenatal diagnosis to the couples with known sickle cell mutation. The sensitivity of ARMS-PCR can be increased by using suitable techniques to detect maternal cell DNA contamination.

Prenatal diagnosis of hemoglobinopathies in Hacettepe University, Turkey

Between 1983 and 2008, prenatal diagnostic procedures for identifying hemoglobinopathies were performed in 947 at-risk fetuses. Seventy-six percent of the fetuses were at risk for β-thalassemia major and 16% for sickle cell anemia; only a small percentage (7%) were at risk for compound heterozygosity of β-thalassemia and an abnormal hemoglobin of the β chain. The results of the study showed that β gene mutations in hemoglobinopathies have a very broad spectrum. Seven hundred and thirty of the 947 fetuses examined using the DNA technique showed 88 different combinations of 27 different mutations. Although the number of fetuses evaluated was far below the desired target, the termination of 261 affected fetuses provided both psychological and economic relief for the parents and was economically beneficial for the country in the long term.

Genetic predisposition to β-thalassemia and sickle cell anemia in Turkey: a molecular diagnostic approach

The thalassemia syndromes are a diverse group of inherited disorders that can be characterized according to their insufficient synthesis or absent production of one or more of the globin chains. They are classified in to α, β, γ, δβ, δ, and εγδβ thalassemias depending on the globin chain(s) affected. The β-thalassemias refer to that group of inherited hemoglobin disorders, which are characterized by a reduced synthesis (β(+)-thalassemia) or absence (β(0)-thalassemia) of beta globin (β-globin) chain production (1). Though known as single-gene disorders, hemoglobinopathies such as β-thalassemia and sickle cell anemia are far from being fully resolved in terms of cure, considering the less complex nature of the beta globin (β-globin) gene family compared to more complex multifactorial genetic disorders such as cancer. Currently, there are no definitive therapeutic options for patients with β-thalassemia and sickle cell anemia, and new insights into the pathogenesis of these devastating diseases are urgently needed. Here we address in detail the overall picture utilizing molecular diagnostic approaches that contribute to unraveling the population-specific mutational analysis of β-globin gene. We also present approaches for molecular diagnostic strategies that are applicable to β-thalassemia, sickle cell anemia, and other genetic disorders.

Incidence of congenital hemolytic anemias in young cholelithiasis patients

AIM: To clarify the incidence of congenital hemolytic anemias (CHA) in young cholelithiasis patients and to determine a possible screening test based on the results.

METHODS: Young cholelithiasis patients (< 35 years) were invited to our outpatient clinic. Participants were asked for comorbidities and family history. The number of gallstones were recorded. Blood samples were obtained to perform a complete blood count, standard Wright-Giemsa staining, reticulocyte count, hemoglobin (Hb) electrophoresis, serum lactate dehydrogenase and bilirubin levels, and lipid profile.

RESULTS: Of 3226 cholecystectomy patients, 199 were under 35 years, and 190 with no diagnosis of CHA were invited to take part in the study. Fifty three patients consented to the study. The median age was 29 years (range, 17-35 years), 5 were male and 48 were female. Twelve patients (22.6%) were diagnosed as thalassemia trait and/or ıron-deficiency anemia. Hb levels were significantly lower (P = 0.046), and mean corpuscular volume (MCV) and hematocrit levels were slightly lower (P = 0.072 and 0.082, respectively) than normal. There was also a significantly lower number of gallstones with the diagnosis (P = 0.007).

CONCLUSION: In endemic regions, for young cholelithiasis patients (age under 35) with 2-5 gallstones, the clinician/surgeon should pay attention to MCV and Hb levels as indicative of CHA.

A Confidential Inquiry Estimating the Number of Patients Affected with Sickle Cell Disease and Thalassemia Major Confirms the Need for a Prevention Strategy in The Netherlands

We have conducted a broad confidential inquiry among 401 hospital departments trying to estimate the number of patients affected with severe forms of hemoglobinopathies living in The Netherlands. With less than 30% response we have registered 559 patients in all age categories of whom 77.0% are affected with sickle cell disease and 17.5% with beta-thalassemia (thal) major. We estimate that the real figure could be around 800 patients, a figure more than six times higher than the number published in 1995 on which the reluctance to offer prevention was based. The actual figures and the incidence estimation of approximately 60 patients a year underline the urgent need for the official implementation of a prevention strategy in The Netherlands. During the last 5 years we have been working towards the implementation of a multi-intervention strategy for primary prevention using the existing structures of public health. The obstacles we have encountered to endorse such a strategy are discussed as a possible guide for other immigration countries.

Preliminary Data on Preimplantation Genetic Diagnosis for Hemoglobinopathies in Turkey

Hemoglobinopathies are the most common genetic diseases in Turkey. Sickle cell anemia is prevalent in the Cukurova region but beta-thalassemia (thal) is seen all over the country. The incidence of sickle cell trait is 10% and beta-thal trait is 3.7% in this region. The families at risk for hemoglobinopathies have come to our center for prenatal diagnosis since 1992. In 15 years, 1,593 fetuses were examined. Four hundred and ten fetuses were found to be homozygous or compound heterozygous for sickle cell anemia and beta-thal. Some mothers had affected fetuses several times. Preimplantation genetic diagnosis (PGD) is an option to avoid the termination of a pregnancy. Studies for PGD of sickle cell anemia were done at Cukurova University Hospital, Cukurova, Adana, Turkey.

Chorionic villus sampling for beta-thalassemia: the first report of experience in Iran

OBJECTIVES

Beta-thalassemia is one of the most common hereditary disorders in Iran. The prenatal diagnosis of beta-thalassemia is part of a control program in our country and it began 13 years ago. During the past 8 years the number of procedures has increased significantly as also the legal abortions. This is the first report made on the CVS program in Iran.

MATERIALS AND METHODS

One thousand six hundred and sixty-one cases of transabdominal Chorionic Villus Sampling (CVS) have been retrospectively evaluated. Among them 1381 cases had inclusion criteria. CVS results, complications and fetal loss rate were evaluated. The distributions of the population at risk were divided between eight regions that have been proposed for beta-thalassemia mapping previously.

RESULTS

The mean age of the patients was 26.2 +/- 5.2 years with mean gestational age of 11.4 +/- 1.4 weeks. CVS was successful in all the patients (100%) although 1% required a second procedure. Post CVS fetal loss was 1.45%. Other minor complications were bleeding or spotting (1.81%), amniotic fluid leak (0.5%), small sub-chorionic hematoma (0.58%), severe abdominal pain (0.6%) and severe vasovagal reaction (0.14%). Late complications were seen in 0.21% (oligohydraminos). Approximately 2/3 of the patients were referred from three regions of the country, North (26.8%), South West (22.4%), Central (19.5%) and the remainder (31.3%) were from the other five regions.

CONCLUSION

CVS is a safe and effective method for prenatal diagnosis of beta-thalassemia in countries with a high prevalence as in Iran. The overall complication rate is quite low and acceptable. Fortunately the recent acceptance of legal abortion with respect to Muslim rules has increased the effectiveness of the procedure and made great advances in its application in Iran. Correspondingly, social knowledge has also improved but still there is a gap between the population at risk and the required prenatal diagnosis laboratories and sampling centers.

Estimating the attitude of immigrants toward primary prevention of the hemoglobinopathies

OBJECTIVES

We conducted population specific confidential enquiries among immigrants who had never experienced hemoglobinopathies, to study the reliability of this approach in estimating the wish for primary prevention by prenatal diagnosis and selective abortion.

METHODS

We collected data from Surinamese Hindustanis (n = 119), Surinamese and Antillean Afro-Americans (n = 105) and North Africans (mainly Moroccans) (n = 102), living in Holland. We also interviewed 105 informed individuals of different ethnicities, all members of the multi-ethnic patients and carriers' organization 'OSCAR Nederland'.

RESULTS

On average, 68% of the Surinamese Hindustanis and 42% of the Surinamese Afro-Americans were in favor of selective abortion in case of affected pregnancy. Remarkably, 77% of the last group wanted to be tested for carrier diagnostics and 67% declared to have knowledge of the disease before they were informed. Only 16% of the Moroccans were in favor of selective abortion in case of an affected fetus, while 79% wanted to have blood analysis to establish their carrier status.

CONCLUSIONS

The apparently limited wish for selective abortion expressed by Moroccans is in contrast with the high number of illegal abortions reported among married women in Morocco (39%). The wish for selective abortion among informed members of the patients' organization was more than 80%.

Spectrum of beta-thalassemia in Jordan: identification of two novel mutations

Two hundred and forty-four beta-thalassemia alleles were identified from 135 unrelated occasionally and periodically transfusion dependent beta- and S/beta-thalassemia patients from all regions of Jordan. Allele identification was achieved by PCR amplification of beta-globin genes, dot-blotting the amplified DNA, hybridization with allele specific synthetic probes, and direct sequencing of amplified genomic DNA. A total of 19 different mutations were detected, eight of them constituted about 86% of the Jordanian thalassemic chromosomes. These mutations were IVS1-110 (G>A) (25%), IVS2-1 (G>A) (15%), IVS2-745 (C>G) (14.2%), IVS1-1 (G>A) (10%), IVS1-6 (T>C) (8.3%), codon 37 (G>A) (6.3%), codon 39 (C>T) (4.6%), and codon 5 (-C) (3.8%). The remaining eleven mutations were rare, presented with frequencies ranging between 0.4% and 1.6%. These included two novel mutations and four others detected in Jordan for the first time. The novel mutations were the frame shift (-C) at codon 49 and the substitution (A>C) at position -29 in the TATA box. Four alleles (1.6%) remained unidentified; having no abnormalities in their beta-globin gene sequences and therefore, constituted additional defects causing beta-thalassemia in the Jordanian population. These unknown alleles are expected to be candidates for upstream or downstream mutations affecting the expression of beta-globin gene. The results provided the essential foundation for planning a national preventive program for thalassemia in Jordan and will help improving the medical services for the patients and their families by helping their clinicians and genetic counselors in evaluating their variants and designing their treatment regimens.

Attitude of Saudi families affected with hemoglobinopathies towards prenatal screening and abortion and the influence of religious ruling (Fatwa)

Hemoglobinopathies are common inherited disorders in Saudi Arabia. Prenatal diagnosis for such diseases is specific and sensitive but not yet implemented in Saudi Arabia. Saudis are Muslims with a very high rate of consanguinity and inherited genetic disorders. To examine the attitude of Saudi families affected with hemoglobinopathies towards prenatal diagnosis and abortion, and to evaluate the effect of education on religious ruling on such attitudes, 32 families were interviewed using a pre-structured questionnaire. The majority accepted prenatal diagnosis (81.3%). The attitude towards abortion was greatly affected by religious values. Education about religious ruling significantly affected parents' attitude towards accepting abortion and prenatal diagnosis. No other factors were found to influence the outcome. Although the majority of families received some kind of formal genetic counseling [23/32 (71.9%)], none of them was informed about the possibility of prenatal or preimplantation diagnosis prior to the interview. Therefore for prevention of genetic disorders, the emphasis in countries with a vast majority of Muslims such as Saudi Arabia has probably to be placed on public awareness about genetic risks, the risk of consanguinity, availability of services, and so on, while at the same time taking into consideration the religious beliefs and education of the target population

Haemoglobinopathies

The inherited haemoglobinopathies are a heterogeneous group of recessive disorders that include the thalassaemias and sickle cell disease. Nearly a thousand mutant alleles have now been characterized. The mutations are regionally specific and in most cases the geographical and ethnic distributions have been determined providing the foundation for a programme of control through screening, genetic counselling and prenatal diagnosis. The main requirements for methodologies providing molecular diagnosis are speed, cost, convenience and the ability to test for multiple mutations simultaneously. For beta-thalassaemia mutations the procedures that meet these requirements are the amplification refractory mutation system and the reverse dot-blot hybridization system. For alpha-thalassaemia the technique of gap PCR is useful for targeting specific deletion mutations but Southern blotting remains the standard diagnostic test.