Molecular characterization of alpha-thalassemia in the Mexican population / Caracterización molecular de talasemia alfa en una población mexicana

ABSTRACT

Background. α-Thalassemia (α-Thal) has been poorly characterized at the molecular level in Mexico. Methods. 106 consecutive individuals identified in Laboratorios Clínicos de Puebla, with either hypochromia (MCH < 24 pg) and/or microcytosis (MCV < 75 fl in women or < 80 fl in man), without iron deficiency, with or without anemia were investigated in this study, along a 16 month-period, α and β-Thal were looked for, the former were characterized at the molecular level. Results. Out of the 106 consecutive cases with hypochromia and/or microcytosis and normal levels of protoporphyrin zinc complex, 48 cases (45.3%) had thalassemia (37 cases of β-Thal and 11 cases of α-Thal), whereas in 58 cases (54.7%) a definite diagnosis could not be established. Of the α-Thal cases, 8 were heterozygous and two were homozygous for the -α3.7 deletion, whereas one case was heterozygous for the α2Hph allele. Conclusions. Only few of the α-Thal alleles tested were found, thus the α-thalassemic mutations, present in the studied population, seem to be rather heterogeneous.

RESUMEN

Antecedentes. En México, la α-talasemia (α-Thal) ha sido pobremente caracterizada a nivel molecular. Mátodos. Se estudiaron 106 individuos consecutivos identificados en los Laboratorios Clínicos de Puebla, con hipocromia (CMH < 24 pg) y lo microcitosis (VCM < 75 fl en mujeres o 80 fl en hombres), sin deficiencia de hierro, con o sin anemia, durante un periodo de 16 meses. Se investigaron α y β-Thal; las primeras fueron caracterizadas a nivel molecular. Resultados. De los 106 casos consecutivos estudiados con hipocromia y/o microcitosis, y niveles normales del complejo de protoporfirina-cinc, 48 casos (45.3%) tenían talasemias (37 de ellos β-Thal y 11 α-Thal), mientras que en 58 casos (54.7%) no pudo establecerse un diagnóstico definitivo. De las talasemias α, ocho casos eran heterocigotos y dos homocigotos para la deleción -α3.7, mientras que sólo un caso resultó heterocigoto para el alelo α2Hph. Conclusiones. De los alelos α-Thal estudiados sólo se encontraron algunos, de lo que se infiere que en la población estudiada esas mutaciones parecen ser bastante heterogáneas.