Phenotypic Effect of α-Globin Gene Numbers on Indian Sickle β-Thalassemia Patients

Abstract

This study indicates that the coexistence of α-globin chain deletions showed mild phenotype instead of absence of α-chain deletions while the patients with triplication of α-genes express severe phenotype.

Association between sickle cell anemia and alpha thalassemia reveals a high prevalence of the α3.7 triplication in congolese patients than in worldwide series

“…This difference may be due to the fact that in their series, the authors included patients with α 3.7 triplication in the without α‐deletion group of patients . Furthermore, in sickle cell β‐thalassemia patients, the presence of an alpha triplication worsens the clinical state …”

Clinical events in a large prospective cohort of children with sickle cell disease in Nagpur, India: evidence against a milder clinical phenotype in India

“…Together, the SC (1,108 castes, 16.6% of the population), ST (744 tribes, 8.6% of the population), and OBC (5,013 castes, 41% of the population) are a diverse group of endogamous communities that constitute a substantial proportion of India's population . Extensive studies of the population distribution of the β s gene in India indicate that it is most prevalent in the ST population, but is also prevalent in many SC and to a lesser extent, OBC populations . Community screening studies for SCD have previously described the distribution of β s in the SC, ST, and OBC populations in Nagpur …”

“…32 Extensive studies of the population distribution of the s gene in India indicate that it is most prevalent in the ST population, but is also prevalent in many SC and to a lesser extent, OBC populations. 5,8,[11][12][13][14][15][16]20,21,33,34 Community screening studies for SCD have previously described the distribution of s in the SC, ST, and OBC populations in Nagpur. 31,34,35…”

“…5,[7][8][9][10] High prevalence of the Arab-Indian globin haplotype, high hemoglobin F levels, high frequency of Xmn1 polymor-phic site, and the coinheritance of -thalassemia are putative potential genetic modifiers contributing to the milder phenotype of SCD in India. 5,8,[11][12][13][14][15][16][17][18][19][20][21] The clinical phenotype in individuals belonging to STs is reported to be milder than that observed in nontribal patients in India. 5,8,[11][12][13][14][15][16][17][18][19][20][21] The aboriginal ST populations have the highest frequencies of the s gene and often, the greatest degree of social isolation and economic disadvantage.…”

Medium-Based Noninvasive Preimplantation Genetic Diagnosis for Human α-Thalassemias-SEA

“…The procedure was slightly modified according to a previous report. 22 Highly specific nested PCR was adapted to detect α-thalassemia -SEA . Nested PCR involves two sets of primers that are used in two successive runs of PCR; the intention of the second set is to amplify a secondary target within the first run product.…”