Novel mutations in the von Hippel–Lindau gene associated with congenital polycythemia

To the editor: Polycythemia is a rare disorder in children and the vast majority of cases are secondary to causes such as cyanotic congenital heart disease, congenital lung diseases, liver and kidney disease, and masses producing erythropoietin. Mutations in exon 3 of the VHL gene are the most common cause of congenital erythrocytosis [1–3]. Several reports have shown evidence of heterozygous and homozygousmutations in exon 2 of theVHL gene as a cause of congenital polycythemia [4–6]. We report on a 9-month-old female who was referred to the hematology clinic for evaluation by her pediatrician with plethora and erythrocytosis (RBC count 7.67million/mm, hemoglobin 21.5 g/dL, hematocrit 66.2%, MCV 86.3 fL). The erythropoietin level was 48 IU/L (normal 4–27), in the face of marked erythrocytosis. The patient was started on phlebotomy treatments of 5ml/kg of blood which has progressed to 10ml/kg of blood with normal saline replacement every 4weeks with good results. Shewas