Prevalence of α(+)-Thalassemia in the Scheduled Tribe and Scheduled Caste Populations of Damoh District in Madhya Pradesh, Central India

Prevalence of hemoglobinopathies among Malayali tribes of Jawadhu hills, Tiruvannamalai district, Tamil Nadu, India: a community-based cross-sectional study

BACKGROUND

Hemoglobin (Hb), a red pigment of red blood cells (RBCs), carries oxygen from the lungs to different organs of the body and transports carbon dioxide back to the lungs. Any fault present in the Hb structure leads to undesirable functional effects of the RBCs, such as sickle cell anemia (SCA), thalassemia, etc. Hemoglobinopathies affect around 7% of people in both developed and developing countries globally. The aim of the present study was to determine the prevalence and carrier frequencies of hemoglobinopathies including SCA, thalassemia, and other abnormal Hb variants among Malayali tribes in the Jawadhu hills of Tiruvannamalai district, Tamil Nadu, India.

METHODS

A community-based cross-sectional study was carried out among 443 Malayali tribes inhabiting the Jawadhu hills of Tiruvannamalai district from July 2022 to September 2022. The RBC indices were analyzed using an automated 5-part hematology analyzer (Mindray, BC-5150) and hemoglobin fractions were done using the HPLC system (Bio-Rad, D-10) following standard protocols.

FINDINGS

A total of 443 participants were screened, out of whom 14.67% had an abnormal Hb fraction, 83.30% were identified as normal, and 2.03% were borderline. Notably, the study revealed a prevalence of 0.68% for the α-thalassemia trait and 13.99% for the β-thalassemia trait.

INTERPRETATION

Haemoglobinopathies, specifically the β-thalassemia trait, were most prevalent among the Malayali tribal population of Tamil Nadu residing in the Jawadhu hills of Tiruvannamalai district. Hence, we need special attention for creating awareness, increasing hemoglobinopathies screening programs, and improving the importance of tribal health conditions by the government and non-governmental organizations (NGOs) for the betterment of the ethnic tribes.

Phenotypic variation in sickle cell disease: the role of beta globin haplotype, alpha thalassaemia and fetal haemoglobin in HbSS

INTRODUCTION

The haematological and clinical feature vary markedly between the different genotypes of sickle cell disease. Even within the single genotype of homozygous sickle cell disease (HbSS), there is marked variability which is presumed to result from interacting genetic and environmental factors.

AREAS COVERED

The classification of the different genotypes of sickle cell disease with approximate prevalence at birth in different communities and some of the major clinical and haematological differences. This assessment includes three potential genetic factors influencing haematology and clinical outcome in HbSS, the beta globin haplotype, alpha thalassaemia and persistence of fetal haemoglobin (HbF).

EXPERT OPINION

The author is a clinician with experience of sickle cell disease primarily in Jamaica but also in Greece, Uganda, Saudi Arabia and India. It is therefore necessarily an account of clinical data and does not address current debates on molecular mechanisms. Most data derive from Jamaica where efforts have been made to reduce any symptomatic bias by long term follow-up of patients all over the island and further reduced by a cohort study based on newborn screening which has been in operation for over 48 years.

Prevalence and Management of β-Thalassemia in India

India bears a huge burden of hemoglobinopathies, and the most prevalent is thalassemia. The different types of thalassemia include minor, major and intermedia, based on the α/β-globin chain inequality. This review aimed to understand the current prevalence of thalassemia in different regions of India and communities affected by it, along with the management of β-thalassemia major (β-TM) and β-thalassemia (β-thal) minor patients. A comprehensive electronic search for relevant articles was conducted using two databases, i.e. PubMed and Science Direct. Articles published in English from India between January 2009 and September 2021 were included. Studies from other countries, genetic and molecular characterization studies, and articles published in other languages were excluded. The prevalence of β-thal trait in Central India ranged between 1.4 and 3.4%, while 0.94% β-TM was reported among the patients with anemia. In South India, the prevalence of β-thal trait was between 8.50 and 37.90% and β-TM was reported to be between 2.30 and 7.47%. Northern and Western Indian states had a higher thalassemic burden. In Eastern India, tribal populations had a higher prevalence of β-thal trait (0.00-30.50%), β-TM (0.36-13.20%) and other hemoglobinopathies [Hb E (HBB: c.79G>A)/β-thal] (0.04-15.45%) than nontribal populations. Additionally, scheduled castes, scheduled tribes and other backward classes of low socioeconomic status and low literacy rates were affected by β-thal. Almost all Indian states reported β-thal; however, it is mostly concentrated in eastern and western parts of the country. Well-integrated strategies and effective implementation are needed at State and National levels to minimize the burden of β-thal.

An online alpha-thalassemia carrier discrimination model based on random forest and red blood cell parameters for low HbA2 cases

BACKGROUND

Since screening of α-thalassemia carriers by low HbA₂ has a low positive predictive value (PPV), the PPV was as low as 40.97% in our laboratory, other more effective screening methods need to be devised. This study aimed at developing a machine learning model by using red blood cell parameters to identify α-thalassemia carriers from low HbA₂ patients.

METHODS

Laboratory data of 1213 patients with low HbA₂ used for modeling was randomly divided into the training set (849 of 1213, 70%) and the internal validation set (364 of 1213, 30%). In addition, an external data set (n = 399) was used for model validation. Fourteen machine learning methods were applied to construct a discriminant model. Performance was evaluated with accuracy, sensitivity, specificity, etc. and compared with 7 previously published discriminant function formulae.

RESULTS

The optimal model was based on random forest with 5 clinical features. The PPV of the model was more than twice the PPV of HbA₂, and the model had a high negative predictive value (NPV) at the same time. Compared with seven formulae in screening of α-thalassemia carriers, the model had a better accuracy (0.915), specificity (0.967), NPV (0.901), PPV (0.942) and area under the receiver operating characteristic curve (AUC, 0.948) in the independent test set.

CONCLUSION

Use of a random forest-based model enables rapid discrimination of α-thalassemia carriers from low HbA₂ cases.

High Prevalence of Anemia and Inherited Hemoglobin Disorders in Tribal Populations of Madhya Pradesh State, India

Despite estimated high prevalence of inherited hemoglobin (Hb) disorders among tribal populations in Madhya Pradesh State, India, the burden of disease is unknown, leading to high morbidity and associated mortality. Our aim was to screen tribal populations in designated tribal districts of Madhya Pradesh State for various hemoglobinopathies and to estimate the prevalence and plausible cause of anemia. The present study screened a total of 3992 tribal individuals comprised of students of Tribal schools, ashrams of Dindori, Mandla, and Chhindwara districts of Madhya Pradesh State. Screening of hemoglobinopathies was done using Hb electrophoresis and or high performance liquid chromatography (HPLC), α-thalassemia (α-thal) was detected using polymerase chain reaction (PCR). The median age of the studied cohort was 15 years (interquartile range 13-16 years). High prevalence (76.7%) of anemia was observed among the studied cohort. The prevalence of sickle cell trait and sickle cell disease varies from 10.7 to 15.6% and 0.4 to 0.8%, respectively. The allele frequency of sickle cell gene was highest in the Pradhan tribe followed by the Panika tribe. Dindori district had the highest prevalence of sickle cell trait. β-Thalassemia (β-thal) trait was observed in only 1.4% of the screened population. α Gene deletions were observed in 84.7% individuals. Significant association of α gene deletion mutations with mean Hb, mean corpuscular volume (MCV), and mean corpuscular Hb (MCH) was observed. The Bharia tribe showed the highest prevalence for α-thal. For comprehensive health care, effective intervention programs are needed to reduce the high prevalence of anemia and hemoglobinopathies among tribes.