Comprehensive analysis of mitochondrial and nuclear DNA variations in patients affected by hemoglobinopathies: A pilot study.

The hemoglobin disorders are the most common single gene disorders in the world. Previous studies have suggested that they are deeply geographically structured and a variety of genetic determinants influences different clinical phenotypes between patients inheriting identical ß-globin gene mutations. In order to get new insights into the heterogeneity of hemoglobin disorders, we investigated the molecular variations on nuclear genes (i.e. HBB, HBG2, BCL11A, HBS1L and MYB) and mitochondrial DNA control region. This pilot study was carried out on 53 patients belonging to different continents and molecularly classified in 4 subgroup: ß-thalassemia (ß+/ß+, ß0/ß0 and ß+/ß0)(15), sickle cell disease (HbS/HbS)(20), sickle cell/ß-thalassemia (HbS/ß+ or HBS/ß0)(10), and non-thalassemic compound heterozygous (HbS/HbC, HbO-Arab/HbC)(8). This comprehensive phylogenetic analysis provided a clear separation between African and European patients either in nuclear or mitochondrial variations. Notably, informing on the phylogeographic structure of affected individuals, this accurate genetic stratification, could help to optimize the diagnostic algorithm for patients with uncertain or unknown origin.

[Hemoglobin variants in Colombian patients referred to discard hemoglobinopathies]. / Variantes de hemoglobina en una población con impresión diagnóstica positiva para hemoglobinopatías en Colombia.

BACKGROUND: Oxygen transport is altered in hemoglobinopathies. AIM: To study the distribution of hemoglobinopathies in Andean subjects without African ancestry. MATERIAL AND METHODS: We analyzed blood samples of 1,407 subjects aged 18 to 59 years (58% females), living in the central Andean region of Colombia, referred to discard hemoglobinopathies. The frequency and type of hemoglobinopathy was established by capillary and agarose gel electrophoresis. RESULTS: The frequency of hemoglobinopathies was 34.5% and higher among females. The structural variants found were: AS-heterozygous hemoglobin (8.1%), homozygous SS (3.7%), heterozygous SC (2.2%), AC heterozygotes (0.5%) and heterozygous AE (0.3%). Quantitative variants found were Hb A-Beta thalassemia (13.91%) and Hb H (0.06%), Beta-thalassemia heterozygotes C (0.88%), S-Beta thalassemia heterozygotes (6.07%) and compound heterozygous SC/Beta thalassemia (0.25%), with a persistence of fetal hemoglobin 0. Composite thalassemia was also found in 31%. All techniques showed good correlation and capillary electrophoresis demonstrated a greater detection of hemoglobin variants. CONCLUSIONS: The frequency of hemoglobin variants in the analyzed population was high, which is an important public health indicator. The most common hemoglobin variant was HbA/Increased structural Hb A2 and the mos frequent structural hemoglobinopathy was sickle cell trait. Capillary electrophoresis can discern any Hb variants present in the population.

Variantes de hemoglobina en una población con impresión diagnóstica positiva para hemoglobinopatías en Colombia / Hemoglobin variants in Colombian patients referred to discard hemoglobinopathies

Background: Oxygen transport is altered in hemoglobinopathies. Aim: To study the distribution of hemoglobinopathies in Andean subjects without African ancestry. Material and Methods: We analyzed blood samples of 1,407 subjects aged 18 to 59 years (58% females), living in the central Andean region of Colombia, referred to discard hemoglobinopathies. The frequency and type of hemoglobinopathy was established by capillary and agarose gel electrophoresis. Results: The frequency of hemoglobinopathies was 34.5% and higher among females. The structural variants found were: AS-heterozygous hemoglobin (8.1%), homozygous SS (3.7%), heterozygous SC (2.2%), AC heterozygotes (0.5%) and heterozygous AE (0.3%). Quantitative variants found were Hb A-Beta thalassemia (13.91%) and Hb H (0.06%), Beta-thalassemia heterozygotes C (0.88%), S-Beta thalassemia heterozygotes (6.07%) and compound heterozygous SC/Beta thalassemia (0.25%), with a persistence of fetal hemoglobin 0. Composite thalassemia was also found in 31%. All techniques showed good correlation and capillary electrophoresis demonstrated a greater detection of hemoglobin variants. Conclusions: The frequency of hemoglobin variants in the analyzed population was high, which is an important public health indicator. The most common hemoglobin variant was HbA/Increased structural Hb A2 and the mos frequent structural hemoglobinopathy was sickle cell trait. Capillary electrophoresis can discern any Hb variants present in the population.

Premarital screening for hemoglobinopathies: experience of a single center in Kurdistan, Iraq.

BACKGROUND: A program for the prevention of major hemoglobinopathies was initiated in 2008 in the Kurdistan region of Iraq. This study reports on the achievements and challenges of the program. METHODS: A total of 102,554 individuals (51,277 couples) visiting a premarital center between 2008 and 2012 were screened for carrier status of hemoglobinopathies, and at-risk couples were counseled. RESULTS: A total of 223 (4.3/1,000) couples were identified and counseled as high-risk couples. Available data on 198 high-risk couples indicated that 90.4% proceeded with their marriage plans, and 15% of these married couples decided to have prenatal diagnosis (PND) in subsequent pregnancies with the identification of 8 affected fetuses; all were terminated as chosen by the parents. Thirty affected births were recorded among the high-risk couples. The premarital program managed to reduce the affected birth rate of major hemoglobinopathies by 21.1%. Of the 136 affected babies born during the study period, 77.9% were born to couples married prior to the start of the program, while 22.1% were born to couples identified as having a high risk. The main reason for not taking the option of PND was unaffordable costs. CONCLUSIONS: Financial support would have increased opting for PND by high-risk couples. Further reduction in affected birth rates could be achieved by including parallel antenatal screening programs to cover those married before the initiation of the premarital program and improving the public health education and counseling programs.

IthaGenes: an interactive database for haemoglobin variations and epidemiology.

Inherited haemoglobinopathies are the most common monogenic diseases, with millions of carriers and patients worldwide. At present, we know several hundred disease-causing mutations on the globin gene clusters, in addition to numerous clinically important trans-acting disease modifiers encoded elsewhere and a multitude of polymorphisms with relevance for advanced diagnostic approaches. Moreover, new disease-linked variations are discovered every year that are not included in traditional and often functionally limited locus-specific databases. This paper presents IthaGenes, a new interactive database of haemoglobin variations, which stores information about genes and variations affecting haemoglobin disorders. In addition, IthaGenes organises phenotype, relevant publications and external links, while embedding the NCBI Sequence Viewer for graphical representation of each variation. Finally, IthaGenes is integrated with the companion tool IthaMaps for the display of corresponding epidemiological data on distribution maps. IthaGenes is incorporated in the ITHANET community portal and is free and publicly available at http://www.ithanet.eu/db/ithagenes.

Classification of the disorders of hemoglobin.

Over the years, study of the disorders of hemoglobin has served as a paradigm for gaining insights into the cellular and molecular biology, as well as the pathophysiology, of inherited genetic disorders. To date, more than 1000 disorders of hemoglobin synthesis and/or structure have been identified and characterized. Study of these disorders has established the principle of how a mutant genotype can alter the function of the encoded protein, which in turn can lead to a distinct clinical phenotype. Genotype/phenotype correlations have provided important understanding of pathophysiological mechanisms of disease. Before presenting a brief overview of these disorders, we provide a summary of the structure and function of hemoglobin, along with the mechanism of assembly of its subunits, as background for the rationale and basis of the different categories of disorders in the classification.

Spectrum of haemoglobinopathies diagnosed by cation exchange-HPLC & modulating effects of nutritional deficiency anaemias from north India.

BACKGROUND & OBJECTIVES: The usefulness of cation exchange high performance liquid chromatography (CE-HPLC) as a tool for detection of thalassaemia/haemoglobin variants was evaluated in a prospective study in a tertiary care centre in north India. We also tried to evaluate the effect of concurrent nutritional deficiency on the HPLC pattern in the local ethnic population. METHODS: A total of 800 blood samples were analyzed on the Bio-Rad Variant HPLC system by ß-thal short program. The retention times, proportion of the haemoglobin (%), and the peak characteristics for all haemoglobin fractions were recorded. Alkaline and acid haemoglobin electrophoresis was performed to document the identities of the haemoglobin variants, wherever necessary. Many cases were subjected to family studies for a definitive diagnosis. RESULTS: Among 800 samples tested, 553 (69.1%) were found to have normal HPLC pattern. Apart from ß- thalassaemia, nine additional variants were encountered; HbS (2.8%), HbE (2.5%) and HbD (1.1%) being the most common variants present. Other variants included Hb Q-India, Hb-Lepore, δß-thalassemia/ HPFH, HbD-Iran, HbJ-Meerut and HbH disease. There was a significant decrease in the level of HbA2 associated with iron deficiency anaemia (IDA) (P=0.004) and increase in megaloblastic anaemia (P<0.001) among subjects with normal HPLC pattern. INTERPRETATION & CONCLUSIONS: HPLC was found to be a simple, rapid and reliable method for the detection of hemoglobin variants. An accurate diagnosis can be provided in majority of cases by use of retention time, proportion of total haemoglobin, and peak characteristics of HPLC. Haemoglobin electrophoresis and family studies play a valuable role in difficult cases. Concurrent nutritional deficiency also has an effect on HbA 2 levels.

Infection outcomes in splenectomized patients with hemoglobinopathies in Australia.

OBJECTIVE: To assess the infection risk of splenectomized persons with hemoglobinopathies in Australia. METHODS: This was an Australia cohort study of infections and vaccinations in 63 patients with hemoglobinopathies followed longitudinally from 1967 to 2006, and an investigation into the risk factors for poor outcome. RESULTS: There were 28 cases of bacterial infection that necessitated hospitalization in the cohort, resulting in an incidence of 1.4 bacterial infections per 100 patient-years. There was one death (1.6%) as a direct result of bacterial infection. Hepatitis C was diagnosed in 28 patients (44%). The spectrum of infection included pneumonia (6/28), cellulitis (6/28), bacteremia (4/28), and skin abscess (3/28). Notably, Klebsiella species organisms were isolated in 9/28 cultures. CONCLUSIONS: Infectious complications in this group of patients cause serious morbidity and mortality. This cohort may be a target for novel preventive strategies such as more immunogenic vaccines, patient registries, and/or education programs.

Types and frequencies of hemoglobin disorders in the pacific coast of four states of Mexico.

INTRODUCTION: Hemoglobin disorders are classified into three main groups: structural variants, thalassemias (thal) and hereditary persistence of fetal hemoglobin (HPFH). OBJECTIVE. This study describes the types and frequencies of hemoglobinopathies from four states of the Pacific coast of Mexico (Jalisco, Colima, Nayarit and Michoacan). MATERIAL AND METHODS. We studied 1513 Mexican individuals by hematological and biochemical analysis following the conventional methods, DNA analysis was carried out in abnormal samples. RESULTS. The frequency of hemoglobinopathies was 1.258%. Structural variants were the most common type (0.726%), with seven carriers (0.462%) and one homozygote (0.066%) for Hb S, and three heterozygotes of the following hemoglobins: C (beta6 Glu-->Lys), Fannin-Lubbock I (beta119 Gly-->Asp) and Colima (beta49 Ser-->Cys), with a frequency of 0.066% each. We observed a frequency of 0.466% for the thalassemia group, with one homozygote for the alpha3.7 (-thal) allele (0.066%), and 6 heterozygotes for beta-thal (0.40%), with the allele IVS1:110 G-->A in three subjects, and the alleles Cd 39, IVS1:5 G-->A and -28 A-->C in the three other. HPFH was detected in one subject (0.066%). Jalisco and Colima had the highest frequencies of hemoglobinopathies, 3.015% and 1.331% respectively, and the latter showed the most diversity of hemoglobin disorders. CONCLUSIONS: The observed heterogeneity of types and frequencies of hemoglobinopathies in the regions studied illustrate the importance of further investigation of these abnormalities in Mexico.

Patología de la hemoglobina en la población española y en la población emigrante / Hemoglobinopathies in Spanish and emigrant population

No disponible

[Hemoglobinopathies--clinical symptoms and diagnosis of thalassemia and abnormal hemoglobins]. / Hämoglobinopathien--Klinik und Diagnostik von Thalassämien und anomalen Hämoglobinen.

Haemoglobinopathies constitute entities that are generated by either an abnormal haemoglobin or thalassaemias. While abnormal haemoglobins are caused by a qualitative structural abnormality of the haemoglobin molecule, thalassaemias result by diminished synthesis of the globin chain. Due to increased immigration from Asia, Africa and the Mediterranean to Northern Europe, haemoglobin S, haemoglobin C, haemoglobin E are also encountered commonly in Switzerland, while other abnormal haemoglobins are rare, yet can cause clinically relevant symptoms. This include haemolysis, polyglobulia, cyanosis or a combination thereof Thalassaemia-syndroms constitute with two million affected individuals to the most prelevant monogenetic diseases worldwide. Due to migration into Switzerland, they are also found quite commonly among our patients with 10-15 per cent of all hypochromic, microcytic, anemia second only to iron deficiency. Importantly, thalassaemias and haemoglobinopathies can occur concomitantly sometimes even with a normal haemoglobin variant. This results in wide-spread presentations, making diagnosis and clinical judgement difficult. We describe in this article not only physiological mechanisms and clinical presentation but also propose a step-wise diagnostic algorithm including selective use of molecular biology methods.

Haemoglobinopathy in pregnancy: diagnosis and treatment.

Haemoglobinopathies differ in geographic prevalence but together are amongst the most common genetic disorders worldwide. Despite huge diagnostic progress, therapeutic options remain limited, with many treatments still at the experimental stage, no more so than in pregnancy: not only does the presence of a fetus subject treatments to greater limitations, but also any worsening of the anaemia as pregnancy progresses results in higher fetomaternal morbidity and mortality. Anaemia weakens the response to peripartum blood loss, with the risk of postpartum complications. Until recently the standard conventional therapy for severe anaemia was (repeated) blood transfusion, with its well-known risks. Recombinant human erythropoietin (rhEPO) can induce fetal haemoglobin and is a safer, if less immediately effective, alternative for the correction of anaemia in pregnant patients with haemoglobinopathy.

Tamizaje de hemoglobinopatías en muestra de la población infantil de Cartagena

Se llevó a cabo un estudio de hemoglobinopatías en una muestra de la población infantil de la ciudad de Cartagena, analizandosa un total de 230 pacientes, 130 masculinos (56,5 por ciento) y 100 femeninos (43,4 por ciento); se encontraron 23 muestras con alteraciones en las hemoglobinas, lo que representa una frecuencia del 10 por ciento

[Diagnosis of hemoglobinopathies and thalassemias]. / Diagnostikk av hemoglobinopatier og talassemier.

During recents the number of immigrants to Norway from Africa and South East Asia has risen considerably. These persons come from countries with a high prevalence of haemoglobinopathies. Most of the immigrants with haemoglobinopathies are silent carriers, but some have a serious disease or have offspring with serious disease. This situation calls for increasing awareness and knowledge of haemoglobinopathies, especially the thalassemias and sickle cell trait. Genetic counselling is particularly important, since the majority of these immigrants marry within small ethnic groups. This paper gives a survey of the most frequent haemoglobinopathies likely to be encountered in Norway.

Cortisol levels in children with haemoglobinopathies in north Jordan.

Serum cortisol levels of 100 children 3-10 years old with various haemoglobinopathies were measured. The mean cortisol levels of sickle cell trait, sickle cell disease, beta-thalassemia minor and alpha 2-thalassemia were significantly (P < 0.05) lower than those of normal subjects. The decrease in cortisol levels varied from 25 (in the sickle cell trait group) to 57 per cent (in the alpha 2-thalassemia group) of the mean cortisol levels of the control group. These results suggest the presence of hypoadrenalism and its possible association with the indicated haemoglobinopathies.

Haemoglobinopathies in a large hospital in Kuwait.

One year experience of various haemoglobinopathies encountered in a large hospital in Kuwait is presented. During the period under study (1988), 84,341 complete blood counts (CBC's) were performed. Haemoglobin electrophoresis was performed in 1289 of these samples; 261 abnormal results were encountered. Almost all the commonly occurring haemoglobinopathies in the world were seen among Kuwaities, probably as a result of inheritance of different haemoglobinopathy genes from different parts of the world. Indirect evidences suggest that alpha thalassemia may be the commonest haemoglobinopathy in Kuwait; a picture not unlike that of Saudi Arabia which is one of its neighbours.