Spectrum of β-thalassemia mutations in the eastern province of Saudi Arabia.

β-Thalassemias comprise a group of heterogeneous hemoglobin (Hb) disorders characterized by the absence or reduced synthesis of the β-globin chain with a variable clinical presentation. The Al-Qatif and Al-Ahsa oases in the Eastern Province of Saudi Arabia are regions known for the high prevalence of these disorders. This study was conducted to provide a more precise picture of the β-thalassemia (β-thal) mutations prevalent in these regions and to estimate their frequencies.

Epidemiology of beta-thalassaemia in Western India: mapping the frequencies and mutations in sub-regions of Maharashtra and Gujarat.

Although the average frequency of beta-thalassaemia carriers in India is 3-4% and the prevalent mutations have been studied, no micromapping has been done. This is the first attempt to provide an accurate estimate of the frequencies of beta-thalassaemia and the expected annual births of homozygous children in different districts of Maharashtra and Gujarat in Western India as well as to determine the molecular heterogeneity in different sub-regions in these states. A total of 18 651 individuals were screened for haemo-globinopathies and mutations were characterized in 1334 beta-thalassaemia heterozygotes.

Regional heterogeneity of beta-thalassemia mutations in the multi ethnic Indian population.

To determine the frequencies of beta-thalassemia mutations in different states of India and to compare this with the available data in Asian Indians for a comprehensive catalogue of molecular defects in the Indian population. beta-thalassemia mutations were characterized in 2456 heterozygotes using reverse dot blot hybridization, ARMS and DNA sequencing. 36 beta-thalassemia mutations were characterized from 18 different states in India.

Hematological and molecular analysis of novel and rare beta-thalassemia mutations in the Indian population.

A variety of mutations causing beta-thalassemia (beta-thal) have been seen in the Indian subcontinent. We report eight families in whom two novel mutations [codon 16 (C>T), IVS-II-613 (C>T)] and three rare mutations [codons 22/23/24 (-7 bp) (-AAGTTGG), -87 (C>A), codon 15 (-T)] were encountered among 375 beta-thal heterozygotes. They were referred to us for molecular characterization or prenatal diagnosis during a period of 2 years.

Prevalence and molecular characterization of alpha-thalassemia syndromes among Indians.

Objective: This study was undertaken to determine the prevalence and molecular basis of alpha-thalassemia in the Indian population and its implications in genetic counseling and prenatal diagnosis.

Methods: 1253 random samples were screened for hemoglobinopathies. Red cell indices were measured on the Sysmex K 1000 cell counter; HbA2 and HbF levels were quantitated using high performance liquid chromotography (HPLC).

Prenatal diagnosis of sickle syndromes in India: dilemmas in counselling.

Objectives: The sickle gene is prevalent in the scheduled caste and tribal populations in India. The clinical presentation of sickle cell disease is extremely variable, and there are no neonatal screening programmes. This is the first report on prenatal diagnosis of sickle syndromes in 85 couples at risk (sickle cell anemia-69; sickle thalassemia-16) from different regions in India.

Prenatal diagnosis in a family at risk for beta-thalassemia and hemophilia A: an uncommon association.

beta-Thalassemia (thal) is an autosomal recessive disorder with a prevalence of 2-3% in Indians, while hemophilia A is X-linked with a prevalence of 1 in 5,000-10,000 male births. The chances of both these disorders being present together is extremely rare (1 in 250,000). We report an interesting consanguineous family from Western India with a combination of these two disorders, which was referred to us for prenatal diagnosis.

Impact of beta globin gene mutations on the clinical phenotype of beta thalassemia in India.

The beta thalassemias are one of the commonest group of autosomal recessive disorders in India. Although majority of patients are severe and transfusion-dependent, about 10-15% of cases have a milder phenotype. We evaluated the role of beta gene mutations in modulating the clinical presentation of 342 beta thalassemia patients which included 278 severe thalassemia major (TM) and 64 thalassemia intermedia (TI) cases (severe TI: 27; mild TI: 37) from this region.

Detection of rare beta-thalassemia mutations by denaturing gradient gel electrophoresis among Indians.

We report four rare beta-thalassemia (thal) mutations, viz. AATAAA --> AACAAA [polyadenylation (poly A) site mutation]. IVS-II-745 (C --> G), codon 121 (G --> T) and IVS-II-1 (G --> A), detected by denaturing gradient gel electrophoresis (DGGE) among Indians.

A novel beta0-thalassemia mutation at codon 55 (-A) and a rare 17 bp deletion at codons 126-131 in the Indian population.

A new mutation at codon 55 (-A) and a rare mutation, a 17 bp deletion at codons 126-131, that gives rise to beta0-thalassemia, were found in the Indian population by means of direct sequencing of two polymerase chain reaction products generated from a 2.3 kb DNA fragment containing the whole beta-globin gene. Each polymerase chain reaction product was sequenced on both strands in a mutation-loading format, showing all nucleotide substitutions or deletions/insertions, including mutations and polymorphisms, in the product.