Identification of a Novel Nonsense Mutation in a Patient with Transfusion-Dependent Hb H Disease.

BACKGROUND: Hb H disease is a form of α-thalassemia. The high clinical variability is influenced by the exact combination of mutations. Here we report on a 29-year-old female patient from Afghanistan who received regular blood transfusions since her childhood. METHODS: For diagnosis we employed Sanger sequencing, multiplex ligation-dependent probe amplification, hemoglobin-electrophoresis, and hematological analysis. RESULTS: Molecular genetic analysis revealed a non-deletional Hb H genotype with two in cis point mutations in HBA1 (c.183G>T;p.Lys61Asn and c.184A>T;p.Lys62*) in addition to the common deletions α4.2 and α3.7 in HBA2. The nonsense-mutation p.Lys62* has not been described before. Hematological data were in accordance with the genetic findings. CONCLUSIONS: We describe here a novel mutation in the HBA1 gene and support evidence for non-deletional type of Hb H leading to transfusion-dependent anemia.