SEVERE β THALASSEMIA IN FRAMESHIFT CODON 6 (–A) HOMOZYGOTES: EFFECTS OF HAPLOTYPE ON PHENOTYPE

The frameshift codon (FSC) 6 ( A) mutation is the most common b-thalassemia (thal) intermedia mutation among the Sardinian population and can also be found in American Blacks and Bulgarians (1–3). The mild effect of this mutation was attributed to its association with the 158 (C!T) mutation at the 50 g promotor region, that is included among point mutations responsible for the hereditary persistence of fetal hemoglobin (HPFH) condition (4). Therefore, FSC 6 ( A) homozygotes or compound heterozygotes with b-thal major-like clinical presentation, deserve extensive studies in order to explain these unexpected conditions. The study presented below gives interesting information about such a condition.