This systematic literature review assessed the global prevalence and birth prevalence of clinically significant forms of alpha- and beta-thalassemia. Embase, MEDLINE, and the Cochrane Library were searched for observational studies published January 1, 2000, to September 21, 2021. Of 2093 unique records identified, 69 studies reported across 70 publications met eligibility criteria, including 6 records identified from bibliography searches. Thalassemia prevalence estimates varied across countries and even within countries. Across 23 population-based studies reporting clinically significant alpha-thalassemia (e.g., hemoglobin H disease and hemoglobin Bart's hydrops fetalis) and/or beta-thalassemia (beta-thalassemia intermedia, major, and/or hemoglobin E/beta-thalassemia), prevalence estimates per 100 000 people ranged from 0.2 in Spain (over 2014-2017) to 27.2 in Greece (2010-2015) for combined beta- plus alpha-thalassemia; from 0.03 in Spain (2014-2017) to 4.5 in Malaysia (2007-2018) for alpha-thalassemia; and from 0.2 in Spain (2014-2017) to 35.7 to 49.6 in Iraq (2003-2018) for beta-thalassemia. Overall, the estimated prevalence of thalassemia followed the predicted pattern of being higher in the Middle East, Asia, and Mediterranean than in Europe or North America. However, population-based prevalence estimates were not found for many countries, and there was heterogeneity in case definitions, diagnostic methodology, type of thalassemia reported, and details on transfusion requirements. Limited population-based birth prevalence data were found. Twenty-seven studies reported thalassemia prevalence from non-population-based samples. Results from such studies likely do not have countrywide generalizability as they tended to be from highly specific groups. To fully understand the global prevalence of thalassemia, up-to-date, population-based epidemiological data are needed for many countries.
Intrapericardial teratoma is a germ-cell tumor that typically arises from the base of the heart. This rare cardiac tumour is the second most common tumor diagnosed in fetuses and newborn. Although benign, it can be massive in size causing direct compression on the heart and associated with significant pericardial effusion resulting life-threatening complications such as cardiac tamponade, heart failure, foetal hydrops, and sudden death. Early antenatal diagnosis and surgical intervention improve the survival. We present a case of immature intrapericardial teratoma diagnosed at 25 weeks of gestation but required multiple foetal pericardiocentesis and premature delivery due to massive pericardial effusion. The importance of multidisciplinary team approach to ensure successful management was highlighted in this case report.
Thalassaemia carriers are common in the Asian region including Malaysia. Asymptomatic patients can be undiagnosed until they present for their antenatal visits. Devastating obstetric outcome may further complicate the pregnancy if both parents are thalassaemia carriers leading to hydrophic fetus due to haemoglobin Bart's disease. However in certain cases where unexplained hydrops fetalis occur in parents with heterozygous thalassaemia carrier,mutated α genes should be suspected. We report a twenty-nine year old woman in her third pregnancy with two previous pregnancies complicated by early neonatal death at 21 and 28 weeks of gestation due to hydrops fetalis. DNA analysis revealed the patient to have heterozygous (--SEA) α-gene deletion, while her husband has a compound heterozygosity for α(3.7) deletion and codon 59 (GGC → GAC) mutation of the α-gene. This mutation, also known as hemoglobin Adana, can explain hydrops fetalis resulting from two alpha gene deletions from the patient (mother) and a single alpha gene deletion with mutation from the father. The third pregnancy resulted in a grossly normal baby boy with 3 α-gene deletions (HbH disease). We postulate that, in view of heterogenisity of the α-thalassaemia in this patient with severely unstable haemoglobin Adana chains from her husband, there will be a 25% possibility of fetal hydrops in every pregnancy.
Haemoglobin Bart's hydrops fetalis is the result of complete absence of functional alpha-globin genes where the fetus is homozygous for the alpha 0-thal gene. Prenatal diagnosis can be made by analysis of fetal DNA from chorionic villus, amniotic cells and fetal blood. Earlier studies for analysing genomic DNA needed digestion with restriction enzymes and hybridisation to radiolabelled probes which took 2 weeks. We have used the polymerase chain reaction (PCR) and non-radioactive primers to identify specific target sequences with results available within 1-3 days for the diagnosis of haemoglobin Bart's syndrome. With fetal blood samples, complete absence of alpha-chain synthesis is confirmed by globin chain electrophoresis on cellulose acetate pH 6.0.
Haemoglobin Bart's hydrops foetalis syndrome (--SEA/--SEA) is not compatible with life and contributes to a majority of the hydropic foetuses in the Malaysian Chinese alpha-thalassaemia carriers who possess the 2-alpha-gene deletion in cis (--SEA/alphaalpha). A duplex-PCR which simultaneously amplifies a normal 136 bp sequence between the psialpha-alpha2-globin genes and a 730 bp Southeast Asian deletion-specific sequence (--SEA) between the psialpha2-theta1-globin genes was established. The duplex-PCR which detects the --SEA deletion in both chromosomes serves as a rapid and cost-effective confirmatory test in the antenatal diagnosis of Haemoglobin Bart's hydrops foetalis syndrome in Malaysia. In addition, the duplex-PCR is simple to perform as both the normal and deletion-specific alpha-globin gene sequences are amplified in the same PCR reaction.
Haemolytic disease of the foetus and newborn (HDFN) is caused by maternal red blood cells (RBC) alloimmunisation resulted from incompatibility of maternal and foetal RBCs. However, only a few HDFN attributed to anti-M were reported, varying from asymptomatic to severe anaemia with hydrops foetalis and even intrauterine death. A case of severe HDFN due to anti-M alloantibody from an alloimmunized grandmultiparous Malay woman with recurrent pregnancy loss is reported here. The newborn was delivered with severe and prolonged anaemia which required frequent RBC transfusions, intensive phototherapy and intravenous immunoglobulin administration. Although anti-M is rarely known to cause severe HDFN, a careful serological work-up and close assessment of foetal well-being is important, similar to the management of RhD HDFN. Alloimmunisation with anti-M type can lead to severe HDFN and even foetal loss.