beta-Thalassemia and hemoglobin types in Argentina: determination of most frequent mutations

Molecular characterization and phenotypical study of β-thalassemia in Tucumán, Argentina

The main hereditary hemoglobin (Hb) disorder in Argentina is β-thalassemia (β-thal). Molecular studies performed in the center of the country exhibited a marked prevalence of the codon 39 (C > T) and IVS-I-110 (G > A) mutations. The northwest region of Argentina has a different demographic history characterized by an important Spanish influx. Seventy-one β-thal carriers attending the Instituto de Bioquímica Aplicada, Tucumán, Argentina, were investigated for β-globin gene mutations by real-time polymerase chain reaction (RT-PCR). To examine the genotype-phenotype relationship, mean corpuscular volume (MCV), mean corpuscular Hb (MCH) and Hb A2 were measured. In order to recognize β-thal, Mentzer Index, Shine & Lal and Red Cell Distribution Width Index (RDWI), were calculated. The ethnic background of subjects revealed that 82.0% of the population was of Italian, Spanish and Arab origin. Seven mutations were detected: codon 39 (45.0%), IVS-I-1 (G > A) (22.5%), IVS-I-110 (16.3%), IVS-II-1 (G > A) (4.1%), IVS-I-1 (G > T) (2.0%), IVS-I-6 (T > C) (2.0%) and IVS-II-745 (G > C) (2.0%). In three families (6.1%), β-thal mutations were not determined. These results differed from other Argentinian studies because at present codon 39 and IVS-I-1 are the most prevalent; MCV, MCH and Hb A2 did not correlate with the type of mutation (β(0)/β(+)). Values of MCV (67.0 fL) and Hb A2 (4.85%) were unable to discriminate between them. Significant differences (p < 0.05) in MCV, MCH and Shine & Lal were observed between the undetermined group and the three most common mutations. These data show different patterns of β-thal mutations in the center and northwest regions of Argentina. Differences might represent the influence of Spanish immigration.

[Early detection of sickle cell anemia and other hemoglobinopathies in neonates in the Autonomous Community of Madrid. A pilot study]

OBJECTIVE

To determine the incidence of sickle cell anemia and other hemoglobinopathies in the neonatal population of the Autonomous Community of Madrid and to determine the need for a screening program.

METHODS

The study was performed with the same blood spot specimen dried on filter paper used for congenital hypothyroidism and congenital adrenal hyperplasia screening. All neonates born in the public and private hospitals of the Autonomous Community of Madrid were included and universal-type screening was performed. High-performance liquid chromatography (HPLC) was used to detect variant hemoglobins. The variant automated system was used to separate and identify hemoglobin F, A1c, A, S, C, A2/E and D. To confirm variant hemoglobins, specific HPLC for -thalassemia (ion exchange) and globin chains (reversed phase) with a more expanded gradient were used.

RESULTS

A total of 29 253 specimens were screened and 98 cases of variant hemoglobins were detected. The overall incidence was 1/299. There were five cases of sickle cell disease (HbFS and HbFS(tal), with an incidence of 1/5.851, and 71 cases of sickle cell traits (1/412).

CONCLUSIONS

These results confirm the need to include screening for sickle cell disease and other hemoglobinopathies in our neonatal program.