These signs correspond to her marked hypochromic, microcytic anemia with erythroid hyperplasia of the bone marrow. beta-Globin genotyping shows here to be compound heterozygous for the codon 39 C-->T beta zero-nonsense mutation and for the T-->C beta(+)-mutation at position 6 of the splice consensus at the exon 1/intron 1 junction (CD39 C-->T/IVS1-6 T-->C). alpha-Globin gene mapping demonstrates the presence of a 3.7-kb alpha (+)-thalassemia deletion on one allele (-alpha 3.7/alpha alpha).
This alpha+-thalassaemia deletion was found to give rise to an atypical haemoglobin H (HbH) disease characterized by a non-transfusion-dependent moderate microcytic hypochromic anaemia in combination with a poly adenylation signal mutation of the alpha-globin gene (alpha2 AATAAA --> AATA-- --).
Inherited deletions of α-globin genes and/or their upstream regulatory elements (MCSs) give rise to α-thalassemia, an autosomal recessive microcytic hypochromic anemia.