Nondeletional alpha-thalassemia: first description of alpha Hph alpha and alpha Nco alpha mutations in a Spanish population.
Several different deletions underlie the molecular basis of alpha-thalassemia. The most common alpha-thalassemia determinant in Spain is the rightward deletion (-alpha 3.7). To our knowledge, however, no cases of alpha-thalassemia due to nondeletional mutations have so far been described in this particular Mediterranean area. Here, we report the existence of nondeletional forms of alpha-thalassemia in ten Spanish families. The alpha 2-globin gene was characterized in ten unrelated patients and their relatives only when the presence of deletional alpha-thalassemia was ruled out. The alpha 2-globin gene analysis was performed using the polymerase chain reaction (PCR) followed by restriction enzyme analysis or by allelespecific priming. This allowed the identification of a 5-base pair (bp) deletion at the donor site of IVS I (alpha Hph alpha) in 9 cases and the alpha 2 initiation codon mutation (alpha Nco alpha) in one case. Although these alpha 2-globin gene mutations are found in other mediterranean areas, our results demonstrate their presence in the Spanish population and suggest that the alpha Hph alpha/alpha alpha genotype is probably the most common nondeletional form of alpha-thalassemia in Spain.
Ayala
S
S
Hematology Laboratory Department, Hospital Clínic i Provincial, Postgraduate School of Hematology Farreras Valentí, University of Barcelona, Catalonia, Spain.
Colomer
D
D
Aymerich
M
M
Pujades
A
A
Vives-Corrons
J L
JL
D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D001483:Base Sequence; D002675:Child, Preschool; D004262:DNA Restriction Enzymes; D005260:Female; D017353:Gene Deletion; D006579:Heterozygote; D006801:Humans; D008297:Male; D015335:Molecular Probes / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D013030:Spain; D017085:alpha-Thalassemia / Q000235:genetics*
D015335:Molecular Probes; D004262:DNA Restriction Enzymes