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The current influx of economic migrants and asylum seekers from countries with a high prevalence of haemoglobinopathies creates new challenges for health care systems and diagnostic laboratories. The migration of carriers introduces new and novel haemoglobinopathy mutations to the diagnostic repertoire of a laboratory, often creating new pressures to improve and update the carrier screening technology and diagnostic scope. For antenatal screening programmes, the marriage of partners from different ethnic groups can lead to the risk of compound heterozygote children being born novel mutation combinations, creating problems in the provision of accurate advice regarding the expected phenotype of the thalassaemia or haemoglobinopathy disorder. In the UK, the impact of immigration required the National Haemoglobinopathy Reference laboratory to change the strategy and techniques used for the molecular diagnosis of thalassaemia and the haemoglobinopathies. In 2005, due to the increasingly large range of β-thalassaemia mutations that needed to be diagnosed, the laboratory switched from a three-step screening procedure using ARMS-PCR to a simpler but more expensive one-step strategy of DNA sequencing of the beta and alpha globin genes for all referrals. After ten years of employing this strategy, a further 57 novel thalassaemia and haemoglobionpopthy alleles were discovered (11 new β-chain variants, 15 α-chain variants, 19 β-thalassaemia mutations and 12 α+-thalassaemia mutations), increasing further the extremely heterogeneous spectrum of globin gene mutations in the UK population. [ABSTRACT FROM AUTHOR]

Although commonly assessed in the context of microcytosis or sickling syndrome screening, hemoglobin mutations may not be as readily considered as a cause of other symptoms. These include macrocytosis with or without anemia, chronic or episodic hemolysis, neonatal anemia, erythrocytosis, cyanosis/hypoxia and methemoglobinemia/sulfhemoglobinemia. Hemoglobin disorders commonly interfere with the reliability of Hb A1c measurement. Because the clinical presentation can be varied and the differential diagnosis broad, a systematic evaluation guided by signs and symptoms can be effective. A tertiary care reference laboratory is particularly challenged by the absence of pertinent clinical history and relevant laboratory findings, and appropriate use of resources in a data vacuum can be problematic. To address these issues, our laboratory has constructed testing panels with a tiered strategy utilizing screening assays that detect the most common causes and reflexing additional assays that assess less common etiologies. See Figure 1. Our testing algorithm panels include a rapid hemoglobin fraction monitoring test, a generic diagnostic hemoglobin electrophoresis profile, and more specific diagnostic evaluations for microcytic anemia, hereditary hemolytic anemia, methemoglobinemia and sufhemoglobinemia and erythrocytosis. Use of these testing strategies has facilitated the identification of rare and complex hemoglobin disorders from a wide variety of ethnic groups, including over 500 distinct named alpha, beta and gamma variants (of which 60+ were novel variants at the time of first detection), 99 beta thalassemia mutations and greater than 20 large deletional beta globin cluster deletion subtypes. [ABSTRACT FROM AUTHOR]

Prenatal diagnosis of hemoglobinopathies involves the study of fetal material from blood, amniocytes, trophoblast coelomatic cells and fetal DNA in maternal circulation. Its first application dates back to the 70s and it involves globin chain synthesis analysis on fetal blood. In the 1980s molecular analysis was introduced as well as amniocentesis and chorionic villi sampling under high-resolution ultrasound imaging. The application of direct sequencing and polymerase chain reaction-based methodologies improved the DNA analysis procedures and reduced the sampling age for invasive prenatal diagnosis from 18 to 16- 11 weeks allowing fetal genotyping within the first trimester of pregnancy. In the last years, fetal material obtained at 7-8 weeks of gestation by coelocentesis and isolation of fetal cells has provided new platforms on which to develop diagnostic capabilities while non-invasive technologies using fetal DNA in maternal circulation are starting to develop. [ABSTRACT FROM AUTHOR]

The β-thalassemias and sickle cell disorders pose a major health burden in the large and diverse Indian population. Education programs for awareness generation are being done by National Institutions, non-governmental organizations and Thalassemia Societies in different states. Several extensive epidemiological studies have shown that there are many non-tribal and tribal communities where the prevalence of β-thalassemia carriers is much higher (5.3 to 17.0%) than the average of 3 to 4% projected for the entire country. These variations have also been shown within small geographic regions in some states, emphasizing the need for micro mapping to estimate the true burden of disease. There are 10 to 12 centers where prenatal diagnosis for hemoglobinopathies is done and the Indian Council of Medical Research is establishing additional regional centers in states where they are most needed. Sixty-eight β-thalassemia mutations have been described so far among Indians and the knowledge on their prevalence and regional distribution has helped to undertake prenatal diagnosis in a cost effective way. [ABSTRACT FROM AUTHOR]

The aims of this study are: i) to enquire whether informing healthy hemoglobinopathy carriers about their condition is a welcome initiative in The Netherlands; ii) to study whether using information letters and thorough explanation is associated with presence or absence of undesired feelings or emotions. We have approached 100 multi-ethnic carriers previously diagnosed in our lab. All subjects had previously received our information letter through their physician who was supposed to have provided an explanation of the letter if required. We have enquired whether the subjects had experienced negative or positive emotions after receiving our diagnosis and explanation and to which degree, if they were sufficiently informed and satisfied and if they would have considered prevention in case of risk. The rate negative versus positive feelings was calculated using a numerical distribution. We have registered negative feelings in a rate that was directly proportional to the lack of information. While the number of registered negative feelings in well-informed carriers was very low it was more present in badly informed. Nevertheless, all participants found carrier information a welcome initiative and over 80% of them declared to be in favor of prenatal diagnosis in case of risk._Carrier information is essential for an informed reproductive choice and is welcome in a multi-ethnic society. Unfortunately, information is not always consequently provided and should therefore be imbedded in the ongoing national screening for Rhesus and infectious diseases available to all women in early pregnancy. [ABSTRACT FROM AUTHOR]

The molecular defects underlying haemoglobinopathies are both deletions and point mutations in the alpha- or beta-globin genes or gene-clusters. To detect point mutations causing alpha- or beta-thalassaemia, direct sequencing is the method of choice to detect the widest spectrum of molecular defects. The most established approach in DNA diagnostics to screen for the most common deletion defects causing alpha-thalassaemia or beta-thalassaemia is gap-PCR, Multiplex Ligation-dependent Probe Amplification (MLPA) and Sanger Sequencing technology to detect breakpoint sequences of previously uncharacterized deletions/duplications. We demonstrate the recent advances in the determination of duplications and deletions causing alpha- or beta-thalassemia, using Next Generation Sequencing, array Comparative Genome Hybridization and Target Locus Amplification. We present three cases in which the use of advanced technologies allow the diagnosis of unexpected disease genotypes. [ABSTRACT FROM AUTHOR]