Dear Editor, The pleiotropic effects of mutations of the band 3 (SCL41/ AE1) gene which result in familial distal renal tubular acidosis (dRTA) and red cell abnormalities are now wellestablished [1]. The occurrence of dRTA and haemolytic anaemia in A858D homozygotes was first reported recently in children from India [2] and Oman [3]. This letter describes certain unusual features in an Omani adolescent A858D homozygote. A 17-year-old Omani Arab youth, son of a consanguineous marriage presented with complaints of bleeding gums and easy bruising for a few weeks. Also, he reported experiencing progressively severe muscle weakness which, after several weeks, culminated in his inability to rise out of bed. He was of normal stature and weight with mild scleral icterus, generalised skin purpura, buccal mucosal petechiae and mild splenomegaly; hypotonia, hyporeflexia and quadriparesis were additional findings. Investigations showed a normal haemoglobin (Hb— 131 g/L), haematocrit (0.39) and white blood cell count, but an increased reticulocyte count (373.5×10/L) and a very low platelet count (6.0×10/L). Freshly drawn blood films revealed polychromasia, a striking predominance of acanthocytes (70–85 %), a moderate number of ovalocytes and a few other poikilocytes (Fig. 1). Ahaptoglobinaemia, unconjugated hyperbilirubinaemia, normal serum immunoglobulins and a negative antiglobulin test provided supportive evidence for a non-immune-compensated haemolysis. The bleeding problem was diagnosed as autoimmune idiopathic thrombocytopenic purpura (ITP) despite negative results of platelet and other relevant autoantibody tests [4]. Associated autoimmune diseases such as SLE and Sjogren's syndrome [5] were ruled out. Quadriparesis was due to hypokalaemia (serum K, 2.5 mmol/L) secondary to complete dRTA characterised essentially by hyperchloraemic acidosis (Cl, 117 mmol/ L), reduced serum HCO3 − (18 mmol/L) concentration and normal values of serum anion gap, blood urea, serum creatinine, arterial blood pH and blood gases, coupled with a positive urine anion gap and a persistent urine pH >6.0; the patient refused a urine acidification test. DNA analysis revealed a homozygous A858D (alanine → aspartic acid) mutation of the SLC41/AE1 gene. Following a 3-week course of oral prednisolone, bleeding symptoms ceased, platelet count was normalised (317×10/ L) and muscle weakness improved considerably on oral potassium chloride, sodium bicarbonate and spironolactone. During the ensuing years, because of poor drug compliance, he was hospitalised several times with hypokalaemic limb pareses (serum K levels varying between 2.0 and 3.1 mmol/L), but his blood counts have remained normal throughout. Ultrasonography later revealed bilateral J. U. Rehman : S. Al Zadjali :N. A. Fawaz : S. Al Kindi Department of Haematology, College of Medicine & Health Sciences, Sultan Qaboos University, PO Box 35, Muscat 123, Sultanate of Oman