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Molecular analysis of complex cases of alpha‐ and beta‐thalassemia in Mexican mestizo patients with microcytosis and hypochromia reveals two novel alpha 0 ‐thalassemia deletions ‐ ‐ Mex1 and ‐ ‐ Mex2
Author(s) -
delaCruzSalcedo E. I.,
Ibarra B.,
RizodelaTorre L. C.,
SánchezLópez J. Y.,
GonzálezMercado A.,
Harteveld C. L.,
PereaDíaz F. J.
Publication year - 2016
Publication title -
international journal of laboratory hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.705
H-Index - 55
eISSN - 1751-553X
pISSN - 1751-5521
DOI - 10.1111/ijlh.12536
Subject(s) - microcytosis , allele , alpha thalassemia , genetics , microcytic anemia , thalassemia , multiplex ligation dependent probe amplification , beta thalassemia , biology , microbiology and biotechnology , medicine , genotype , anemia , gene , iron deficiency , exon
Summary Introduction Alpha‐thalassemia (α‐thal) is a common monogenic disorder worldwide. In mixed ethnic populations, α‐thal and beta‐thalassemia (β‐thal) can be expected, sometimes giving complex phenotypes, which without molecular analysis are not easily explained. We performed the molecular identification of α‐ and β‐thal alleles in 51 Mexican patients with microcytosis, hypochromia, and normal or low levels of HbA 2 . Methods Common deletional alleles (‐α 3.7 , ‐α 4.2 , ‐ ‐ SEA , ‐ ‐ MED , ‐ ‐ FIL , ‐ ‐ THAI , ‐α 20.5 ) and α‐triplication were studied by gap‐ PCR and nondeletional alleles (α IVSI (−5nt) , α 2 NcoI , α 1 NcoI ) by ARMS . β‐thal alleles Cd39 (C>T), IVS 1:1 (G>A), IVS 1:110 (G>A), and Spanish δβ‐thal were also investigated. DNA sequencing was performed on HBA 2 , HBA 1 , and HBB genes. Negative samples were subjected to MLPA . Results In 35 subjects, we identified the mutations, ‐α 3.7 , ‐ ‐ SEA , ‐ ‐ FIL , α IVSI (−5nt) , and ααα anti3.7 and two novel deletion alleles ‐ ‐ Mex1 (6.8–8.9 kb) and ‐ ‐ Mex2 (77.6–135.7 kb). Four individuals also had a β‐thal allele (Cd39/ IVS 1:110). No α‐thal alleles were observed in 16 subjects, but three had a β‐thal mutation Cd39, IVS 1:110, and Spanish δβ‐thal. Conclusion α‐thal is relatively common in Mexican patients, the combination with β‐thal is sometimes unexpected, and this underlines the importance of performing molecular analysis for both α‐ and β‐genes defects in patients showing microcytic hypochromic anemia.