First reported case of compound heterozygosity for HbA2-Yialousa (HBD: c.82 G>C) and HbA2-Wrens (HBD: c.295 G>A) in Oman

Haemoglobin Fontainebleau (HBA2: c. 64G>C) in Oman: molecular and haematological characteristics and interaction with various haemoglobinopathies

Objectives

To describe the laboratory features of haemoglobin Fontainebleau (Hb FB) and its interactions with various α and β globin gene mutations in the Omani population.

Methods

Over a period of 10 years, a total of 94 blood samples were suspected to have an α variant on HPLC at the Sultan Qaboos University Hospital, Muscat, Oman. Molecular testing was performed using PCR based techniques to define the variant and to analyse other interacting mutations in either α or β globin genes.

Results

Of 94 subjects, molecular analysis confirmed the Hb FB variant in 55 samples (38 non-cord and 17 cord blood). A total of 36/38 non-cord samples were heterozygous for the variant, while all 17 cord blood samples were heterozygotes. A total of 43/55 individuals had a concomitant α and/or β globin gene mutation.

Conclusions

Hb FB is the the most common α variant in the Omani population. We report the different HPLC profiles of this variant that we observed, with and without other haemoglobinopathies in non-cord and cord blood samples. This is the first report describing the HPLC profiles of this α globin chain variant on 1 year follow-up testing of cord blood samples. With careful analysis by HPLC, it is possible not only to identify Hb FB but also to predict any concomitant α and/or β globin gene mutations.