The Prevalence and Molecular Basis of Hemoglobinopathies in Cambodia

Abstract

Blood counts, hemoglobin (Hb) high performance liquid chromatography (HPLC), and DNA analyses were performed on 260 children, aged 5 months to 16 years, at Siem Reap to assess the prevalence of thalassemia and other hemoglobinopathies in regional Cambodia. Hemoglobinopathies were present in 134 children (51.5%) with 20 abnormal genotypes identified. alpha-Thalassemia (thal) (35.4%) was the most prevalent disorder and the -alpha3.7 gene deletion was the most common alpha-globin gene abnormality. The - -SEA deletion and nondeletional forms of alpha-thal, Hb Constant Spring [Hb CS, alpha142, Term-->Gln, TAA-->CAA (alpha2)], Hb Paksé [alpha142, Term-->Tyr, TAA-->TAT (alpha2)] and triplicated alpha genes, were also present but at low frequencies. Hb E [beta26(B8)Glu-->Lys, GAG-->AAG] (28.8%) was the most common beta-globin gene abnormality, whilst beta-thal was only detected in two children (0.8% of cases). Although hemoglobinopathies were common, the majority of abnormalities detected (heterozygous -alpha3.7 and Hb E) were not clinically significant. On the basis of these findings, and with the majority of abnormalities being mild, it seems improbable that thalassemia represents a major health burden in this region of Cambodia.

Prevalence of Anemia and Underlying Iron Status in Naive Antiretroviral Therapy HIV-Infected Children with Moderate Immune Suppression

“…11,18 Up to 25-35% of Thai and Cambodian people are carriers of a-thalassemia, and up to 60% of Thai and Cambodian people are carriers of hemoglobin E. 11,36 Although the heterozygotes for a-thalassemia 1, b-thalassemia, and HbE typically are asymptomatic, they may cause mild microcytic, hypochromic anemia. 18 In this study, we used the most reliable method (DNA analysis) to detect common thalassemia mutations or deletions of a-and b-genes and found that 125/299 (41.8%) of the study population had underlying thalassemia (Table 3), mainly the thalassemia trait.…”

“…13 IDA [3][4][5][6][7][8][9][10][11][12][13][14][15] was defined as anemia with (1) serum ferritin < 10 lg/ml if CRP was < 10 mg/liter or serum ferritin < 50 lg/ml if CRP was ‡ 10 mg/liter 16,17 and (2) having at least three of the following five parameters: (1) SI < 8.8 lmol/liter, (2) TIBC > 71.6 lmol/liter, (3) TS < 10%, (4) mean corpuscular volume (MCV) less than normal age-related values ( < 2 years = 78 fl, ‡ 2 years = 81 fl), or (5) mean corpuscular hemoglobin (MCH) less than normal age-related values ( < 2 years = 23 pg, 2-5 years = 24 pg, and ‡ 6 years = 25 pg). 14,15 Nonthalassemia was defined as having no common thalassemia mutations or deletions of a-and b-genes.…”

“…1 Gaps exist as to anemia prevalence and causes in HIV-infected children with mild disease status in Southeast Asian countries where thalassemia is common. [9][10][11] We evaluated the iron status, prevalence, and causes of anemia in antiretroviral therapy (ARV)-naive HIV-infected children without advanced HIV infection to determine the necessity of routine iron supplementation.…”

Genetic Hemoglobin Disorders, Infection, and Deficiencies of Iron and Vitamin A Determine Anemia in Young Cambodian Children

“…However, anemia of this type is also associated with both vitamin A deficiency (3) and genetic Hb 11 disorders that affect the structure, function and/or production of Hb (4). The occurrence of both of these conditions is well documented in Cambodian children (5)(6)(7)(8).…”

“…Two genetically distinct variants are common: Hb E and a-thalassemia (6,9); their frequency varies with geographic region. Hb E disease arises from a genetic alteration in the physical structure of Hb, specifically a single amino acid substitution in one of the bglobin chains.…”