Clinical Implications of HbD-Punjab and HbS co-Inheritance - A Rare Case in South India

HbD-Punjab is prevalent in the north-western region of India with an estimated frequency of 2% in Punjab. The association of HbD-Punjab with HbS results in moderate-severe symptoms which are similar to the HbSS homozygous phenotype. Simultaneous presence of variant HbD with HbS favors polymerization of HbS molecules which results in serious consequences like sickle vaso-occlusion leading to diminished flow of blood through the capillaries supplying the bones resulting in ischemia, avascular necrosis, infarcts of bone, untimely closure of epiphyseal plates and stunted growth. This study describes a brief incident where a 28-year-old female, who presented with left sided hip pain, diagnosed with left hip femoral head Avascular Necrosis (AVN) (Grade-3). She was diagnosed with sickle cell anemia in a regional hospital at the age of six years and had undergone multiple blood transfusions. She had a history of right total hip replacement, left knee synovectomy and pain in multiple joints, including both the knees, elbows and shoulders. In view of severe anemia, hemoglobin fractionation was done using HPLC method which was suggestive of double heterozygous Hb SD-Punjab, genetic and family studies were recommended and there was no significant family history. This study enlightens the occurrence of adverse consequences in the presence of a double heterozygous Hb variant with one of the variants being Hb S. Laboratory investigations for identification and characterization of such variant hemoglobin is important for preventive and palliative care.