Unusual phenotypic observations associated with a rare HbH disease genotype (‐ ‐Med/αTSaudiα): implications for clinical management

A single patient with a rare Haemoglobin H (HbH) disease genotype (- -Med/alphaTSaudialpha) was observed to have exceptionally high levels of HbH (> 60%) and paradoxically high total haemoglobin levels. Studies of haematological parameters, blood biochemistry and oxygen transport properties revealed a severe functional anaemia, associated with marked erythropoietic stimulation and a markedly raised cardiac output. This rare case illustrates the complexity of interactions that may be associated with the clinical course of HbH disease, highlighting that haematological parameters alone may lead to spurious evaluation of clinical status. Issues related to the therapeutic management of unusual cases are raised.