Hb H hydrops foetalis syndrome: a case report and review of literature

Haemoglobin H (Hb H) disease is caused by deletion or inactivation of three alpha -globin genes, leaving only one intact and active alpha -globin gene. People with Hb H disease usually have moderate anaemia, but are generally thought to be asymptomatic. Some Rb H disease patients require transfusions, and there are reports of fetuses with Rb H disease who have severe anaemia in utero resulting in fatal hydrops foetalis syndrome. We now report a case of Hb H hydrops foetalis syndrome, caused by the inheritance of a hitherto novel alpha -globin gene point mutation (codon 35 TCC-->CCC or Serine-->Proline) and an alpha -thalassaemia deletion of the Filipino type removing all zeta-alpha -globin genes on the other chromosome 16. The infant was delivered prematurely because of pericardial effusion and fetal distress, and was found to have severe anaemia ard congenital anomalies. A review of the relevant literature on this syndrome is presented, and serves to underscore the phenotypic variations of Hb H disease and the need for surveillance for this condition among newborns and genetic counselling in communities with a high proportion of at-risk populations.