Reproductive carrier screening started in some countries in the 1970s for hemoglobinopathies and Tay-Sachs disease. Cystic fibrosis carrier screening became possible in the late 1980s and with technical advances, screening of an ever increasing number of genes has become possible. The goal of carrier screening is to inform people about their risk of having children with autosomal recessive and X-linked recessive disorders, to allow for informed decision making about reproductive options. The consequence may be a decrease in the birth prevalence of these conditions, which has occurred in several countries for some conditions. Different programs target different groups (high school, premarital, couples before conception, couples attending fertility clinics, and pregnant women) as does the governance structure (public health initiative and user pays). Ancestry-based offers of screening are being replaced by expanded carrier screening panels with multiple genes that is independent of ancestry. This review describes screening in Australia, Cyprus, Israel, Italy, Malaysia, the Netherlands, Saudi Arabia, the United Kingdom, and the United States. It provides an insight into the enormous variability in how reproductive carrier screening is offered across the globe. This largely relates to geographical variation in carrier frequencies of genetic conditions and local health care, financial, cultural, and religious factors.
Matched MeSH terms: Prenatal Diagnosis/statistics & numerical data
Objectives: Chromosomal abnormalities especially aneuploidies are the most common etiology for pregnancy loss. Trisomy 13, trisomy 18 and trisomy 21 are the most common chromosome autosomal aneuploidies with trisomy 21 (Down syndrome) being the most common chromosomal abnormality among liveborn infants. In previous reports, we noted that the recurrence of these aneuploidies in some families may not occur by chance alone.
Methods: Extraction of relevant data from review of medical case notes of a young couple with two offspring with Down syndrome (DS) and Patau syndrome.
Results: A family history of DS is a predisposing factor for both DS and other types of aneuploidy. Certain instances of non-disjunction error are not random.
Conclusion: As the maternal age was not advanced in both pregnancies, there is a possibility that the recurrent aneuploidy in this family may not be accounted by chance alone. The risk of having subsequent affected pregnancy cannot be ignored in this family and prenatal diagnosis is strongly recommended in the subsequent pregnancy.
Beta-thalassemia major patients have chronic anemia and are dependent on blood transfusions to sustain life. Molecular characterization and prenatal diagnosis of beta3-thalassemia is essential in Malaysia because about 4.5% of the population are heterozygous carriers for beta-thalassemia. The high percentage of compound heterozygosity (47.62%) found in beta-thalassemia major patients in the Thalassaemia Registry, University of Malaya Medical Centre (UMMC), Malaysia, also supports a need for rapid, economical, and sensitive protocols for the detection of beta-thalassemia mutations. Molecular characterization of beta-thalassemia mutations in Malaysia is currently carried out using ARMS, which detects a single beta-thalassemia mutation per PCR reaction. We developed and evaluated Combine amplification refractory mutation system (C-ARMS) techniques for efficient molecular detection of two to three beta-thalassemia mutations in a single PCR reaction. Three C-ARMS protocols were evaluated and established for molecular characterization of common beta-thalassemia mutations in the Malay and Chinese ethnic groups in Malaysia. Two C-ARMS protocols (cd 41-42/IVSII #654 and -29/cd 71-72) detected the beta-thalassemia mutations in 74.98% of the Chinese patients studied. The CARMS for cd 41-42/IVSII #654 detected beta-thalassemia mutations in 72% of the Chinese families. C-ARMS for cd 41-42/IVSI #5/cd 17 allowed detection of beta-thalassemia mutations in 36.53% of beta-thalassemia in the Malay patients. C-ARMS for cd 41-42/IVSI #5/cd 17 detected beta-thalassemia in 45.54% of the Chinese patients. We conclude that C-ARMS with the ability to detect two to three mutations in a single reaction provides more rapid and cost-effective protocols for beta-thalassemia prenatal diagnosis and molecular analysis programs in Malaysia.
Beta-thalassemia is the most-common genetic disorder of hemoglobin synthesis in Malaysia, and about 4.5% of the population are heterozygous carriers of the disorder. Prenatal diagnosis was performed for 96 couples using the Amplification Refractory Mutation System and Gap-Polymerase Chain Reaction. We identified 17 beta-globin defects-initiation codon for translation (T-G), -29 (A-G), -28 (A-G), CAP +1 (A-C), CD 8/9 (+G), CD 15 (G-A), CD 17 (A-T), CD 19 (A-G), Hb E (G-A), IVS1-1 (G-T), IVS1-5 (G-C), CD 41/42 (-CTTT), CD 71-72 (+A), IVS2-654 (CT), poly A(A-G), 100-kb Ggamma(Agammadeltabeta) degrees and 45-kb Filipino deletions. The 192 beta-alleles studied comprised Chinese (151 patients), Malay (21), Orang Asli from East Malaysia (15), Filipino (1), Indian (1), Indonesian Chinese (2), and Thai (1). In the Chinese, 2 beta-globin defects at CD 41/42 and IVS2-654 were responsible for 74% of beta-thalassemia. beta-mutations at CD 19, IVS1-1 (G-T), IVS1-5, poly A, and hemoglobin E caused 76% of the hemoglobin disorders in the Malays. The Filipino 45-kb deletion caused 73.3% of bthalassemia in the Orang Asli. Using genomic sequencing, the rare Chinese beta-mutation at CD 43 (G-T) was confirmed in 2 Chinese, and the Mediterranean mutation IVS1-1 (G-A) was observed in a Malay beta-thalassemia carrier. The beta-globin mutations confirmed in this prenatal diagnosis study were heterogenous and 65 (68%) couples showed a different globin defect from each other. The use of specific molecular protocols has allowed rapid and successful prenatal diagnosis of beta-thalassemia in Malaysia.
The treatment of heart failure in pregnant women is more difficult than in non-pregnant women, and should always involve a multidisciplinary team approach. Knowledge required includes hemodynamic changes in pregnancy and the resultant effect on women with pre-existing or pregnancy-related cardiovascular disease, cardiovascular drugs in pregnancy, ethical issues and challenges regarding saving mother and baby. In addition, women having high risk cardiac lesions should be counselled strongly against pregnancy and followed up regularly. Pregnancy with heart failure is an important issue, demanding more comprehensive studies.
The distribution of restriction fragment length polymorphism (RFLP) at the BamH1 site of the beta-globin gene was investigated in the Chinese, Indian, and Malay race in Singapore. The sample comprised of 183 normal individuals and 35 beta-thalassemia carriers in which 13 were couples with at least one beta-major child. The results from this study indicate that BamH1 polymorphism will be informative in 22% of pregnancies at risk for beta-thalassemia major in Chinese, 19% in Malays and 7% in Indians. In prenatal diagnosis using BamH1 polymorphism for one beta-major affected family, the fetus was diagnosed to be normal or beta-carrier. The validity of BamH1 polymorphism in the exclusion of beta-thalassemia major was subsequently confirmed at birth by globin chain biosynthesis.
The different methods of prenatal diagnosis are discussed with special reference to ultrasound scan, amniocentesis for cell culture with processing for chromosome study, biochemical analysis and DNA recombination analysis. Chorionic villi aspiration and fetoscopy are new methods which will enhance considerably the methods for prenatal diagnosis. With regard to chromosome study of amniotic cells, experience with 623 cases is reviewed. 2.7% demonstrated chromosome anomalies and of these Downs anomaly was the commonest. A large proportion of cases requesting for amniocentesis are Caucasians who represent only 2% of the population in Singapore, but 25% of the 440 requests were from Caucasions. The various problems associated with the different methods for prenatal deafness are discussed.
α°-thalassemia is a well-known cause of hydrops fetalis in South-East Asia and can be detected in utero. We report a very rare case of thyrotoxic cardiomyopathy associated with hyperplacentosis secondary to α°-thalassemia-associated hydrops fetalis. A 22-year-old primigravida with microcytic anemia presented at 27 weeks' gestation with pre-eclampsia, hyperthyroidism and cardiac failure. Serum β-human chorionic gonadotrophin was markedly elevated and abdominal ultrasound revealed severe hydropic features and enlarged placenta. Serum β-human chorionic gonadotrophin, cardiac function and thyroid function tests normalized after she delivered a macerated stillbirth. Histopathology of the placenta showed hyperplacentosis. Blood DNA analysis revealed that both patient and husband have the α°-thalassemia trait. This case illustrates a very atypical presentation of α°-thalassemia-associated hydrops fetalis and the importance of early prenatal diagnosis of α-thalassemia in women of relevant ethnic origin with microcytic anemia so that appropriate genetic counseling can be provided to reduce maternal morbidity and the incidence of hydrops fetalis.
OBJECTIVE: We sought to evaluate the psychometric properties of two widely used screening scales: the Patient Health Questionnaire (PHQ-9) and Edinburgh Postnatal Depression Scale (EPDS) among pregnant Peruvian women.
METHODS: This cross-sectional study included 1517 women receiving prenatal care from February 2012 to March 2013. A structured interview was used to collect data using PHQ-9 and EPDS. We examined reliability, construct and concurrent validity between two scales using internal consistency indices, factor structures, correlations, and Cohen׳s kappa.
RESULTS: Both scales had good internal consistency (Cronbach׳s alpha>0.8). Correlation between PHQ-9 and EPDS scores was fair (rho=0.52). Based on exploratory factor analysis (EFA), both scales yielded a two-factor structure. EFA including all items from PHQ-9 and EPDS yielded four factors, namely, "somatization", "depression and suicidal ideation", "anxiety and depression", and "anhedonia". The agreement between the two scales was generally fair at different cutoff scores with the highest Cohen׳s kappa being 0.46.
CONCLUSIONS: Both the PHQ-9 and EPDS are reliable and valid scales for antepartum depression assessment. The PHQ-9 captures somatic symptoms, while EPDS detects depressive symptoms comorbid with anxiety during early pregnancy. Our findings suggest simultaneous administration of both scales may improve identification of antepartum depressive disorders in clinical settings.
Frontoethmoidal meningoencephaloceles (FEM) are exceedingly rare in the western hemisphere, Australia, and Europe with an estimated frequency of 1 in 40,000 live births. Among the inhabitants of Thailand, Burma, Malaysia, Indonesia, and parts of the Soviet Union, however, the frequency is as high as 1 in 5000, accounting for 15% of all neural tube defects (NTD). Normal maternal serum alpha-fetoprotein (MSAFP) values usually will be found in these cases since most encephaloceles are closed, skin covered defects. Correct interpretation of the sonographic findings is crucial in establishing a diagnosis as well as giving prognostic and recurrence risk information. To our knowledge, this is the first reported case of prenatally diagnosed FEM. Perinatal management, differential diagnosis for disorders associated with this malformation, and epidemiologic information regarding this rare condition are discussed. It is anticipated that the prenatal sonographic findings may be applied to establish this diagnosis in similarly affected fetuses.
The Mi III phenotype of the Miltenberger subsystem (or GP Mur) is relatively common in Southeast Asia especially along the south-east coast lines of China and Taiwan. The term anti-"Mia" describes antibodies that react with the Mi III phenotype. Since the Peninsula Malaysian population is a multiethnic one with a significant proportion of Chinese, a study was conducted into the prevalence of anti-"Mia" in patients from its 3 major ethnic groups--Chinese, Malays and Indians, as well as the GP Mur phenotype in blood donors (healthy individuals). Blood samples from 33,716 patients (general and antenatal) were screened for anti-"Mia" from January 1999 to December 2000. The investigation for the GP Mur phenotype representing the corresponding sensitizing antigen complex was carried out in 655 blood donors. Serum anti-"Mia" antibody was found to be the third most commonly occurring antibody detected in our patients and was found in all the ethnic groups. The antibody was detected in 0.2% of 33,716 antenatal and general patients with a prevalence in Chinese of 0.3%, Malay 0.2% and Indian 0.2%. The detection of these antibodies in the ethnic groups other than the Chinese is a noteworthy finding as such information is not well documented. The GP Mur red cell phenotype was detected in 15/306 (4.9%) of Chinese blood donors, a lower prevalence than in Chinese populations in other countries in the region. More significant was its detection in the Malays (2.8%) and the Indians (3.0%). Because of the many reports of clinical problems associated with the "Mia" antibody including the causation of fetal hydrops and haemolytic transfusion reactions, it is warranted that the GP Mur red cells be included in screening panels for group and screen procedures in countries with a significant Asian population.
Prenatal diagnosis is a rapidly evolving speciality. Screening for aneuploidy begins with non-sonographic features of background risk of maternal age and past and family history. It is possible to diagnose major structural defects in the foetus using second trimester scans. Serum biochemistry markers in the early second trimester were added to increase the detection rate of aneuploidy. However, as some of these abnormalities were amenable to detection earlier in the first trimester, newer modalities were introduced. Nuchal translucency (NT) measurement was one of the main advances with regard to first trimester screening. Additional markers such as the presence of nasal bone, tricuspid regurgitation, ductus venosus and megacystis; together with first trimester serum biochemistry, further enhanced the detection rate of chromosomal abnormalities. Advances in research and technology have resulted in the availability of non-invasive prenatal testing from 10 weeks of gestation. This has facilitated the detection of the three major chromosomal aneuploidies at very early gestation. However, there are a wide range of genetic syndromes that are not confined to the main trisomies. There are specific markers on ultrasound that can be linked to specific syndromes. Hence, a structured and stepwise approach is needed to identify and reach a possible diagnosis. As anomalies are classified into malformations, deformations and disruptions, it is important to note that not all markers detected are due to genetic syndromes and not all genetic syndromes can be detected on ultrasound scan. In this chapter, we outline common structural markers and their association with main genetic syndromes.
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.
BACKGROUND/AIMS: Individuals with double heterozygosity for alpha- and beta-thalassaemia and heterozygous beta-thalassaemia show a similar haematological picture. Co-inheritance of alpha- and beta-thalassaemia in both partners may result in pregnancies with either Hb Bart's hydrops foetalis or beta-thalassaemia major, or pregnancies with both disorders.
METHODS: The co-inheritance of alpha-thalassaemia in 322 beta-thalassaemia carriers in Malaysia was studied.
RESULTS: The frequency of alpha-thalassaemia in the beta-thalassaemia carriers was 12.7% (41/322), with a carrier frequency of 7.8% for the SEA deletion, 3.7% for the -alpha(3.7) deletion, 0.9% for Hb Constant Spring and 0.3% for the -alpha(4.2) deletion.
CONCLUSION: Double heterozygosity for alpha- and beta-thalassaemia was confirmed in 5 out of the 41 couples and the risk of the fatal condition Hb Bart's hydrops foetalis was confirmed in two of these couples. Detection of the Southeast Asian (SEA) deletion in the Malaysian Malays in this study confirms that Hb Bart's hydrops foetalis can occur in this ethnic group. Results of this study have provided new information on the frequency and different types of alpha-thalassaemia (--(SEA), -alpha(3.7) and -alpha(4.2) deletions, Hb Constant Spring) in Malaysian beta-thalassaemia carriers.
Homozygosity for the α-thalassaemia Southeast Asian (α-SEA) and Filipino β°-thalassaemia (β-FIL) deletions can cause serious complications leading to foetal death or life-long blood transfusions. A rapid and accurate molecular detection assay is essential in populations where the deletions are common. In this study, gap-polymerase chain reaction (PCR) with high resolution melting (HRM) analysis was developed to detect both the large deletions. Melting curves at 86.9 ± 0.1 °C were generated by normal individuals without the α-SEA deletion, 84.7 ± 0.1 °C by homozygous α-SEA deletion individuals and two melting curves at 84.7 ± 0.1 °C and 86.9 ± 0.1 °C by α-SEA deletion carriers. Normal individuals without the β-FIL deletion produce amplicons with a melting temperature (Tm) at 74.6 ± 0.1 °C, homozygous β-FIL individuals produce amplicons with Tm at 73.6 ± 0.1 °C and heterozygous β-FIL individuals generate two amplicons with Tm at 73.6 ± 0.1 °C and 74.6 ± 0.1 °C. Evaluation using blinded tests on 220 DNA samples showed 100% sensitivity and specificity. The developed assays are sensitive and specific for rapid molecular and prenatal diagnosis for the α-SEA and β-FIL deletions.
Hemoglobin disorders which include thalassemias are the most common heritable disorders. Effective treatment is available, and these disorders can be avoided as identification of carriers is achievable using simple hematological tests. An in-depth understanding of the awareness, attitudes, perceptions, and screening reservations towards thalassemia is necessary, as Malaysia has a multi-ethnic population with different religious beliefs. A total of 13 focus group discussions (70 participants) with members of the general lay public were conducted between November 2008 and January 2009. Lack of knowledge and understanding about thalassemia leads to general confusions over differences between thalassemia carriers and thalassemia major, inheritance patterns, and the physical and psychologically impact of the disorder in affected individuals and their families. Although most of the participants have not been tested for thalassemia, a large majority expressed willingness to be screened. Views on prenatal diagnosis and termination of fetuses with thalassemia major received mixed opinions from participants with different religions and practices. Perceived stigma and discrimination attached to being a carrier emerged as a vital topic in some group discussions where disparity in the answers exhibited differences in levels of participants' literacy and ethnic origins. The two most common needs identified from the discussion were information and screening facilities. Participants' interest in knowing the severity of the disease and assessing their risk of getting the disorder may imply the health belief model as a possible means of predicting thalassemia public screening services. Findings provide valuable insights for the development of more effective educational, screening, and prenatal diagnostic services in the multi-ethnic Asian society.
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.