Selective malabsorption of vitamin B12 without proteinuria or structural renal tract anomaly.

Selective malabsorption of vitamin B12 without proteinuria or structural renal tract anomaly The first reports by Imerslund' and Grasbeck2 of children presenting with a megaloblastic anaemia due to vitamin B1 2 deficiency but with normal gastric intrinsic factor activity (Imerslund-Grasbeck syndrome or selective malabsorption of vitamin BI 2) described associated proteinuria. In a review of 49 patients who had been examined for proteinuria, Visakorpi and Furuhjelm' showed that 44 patients had persistent proteinuria. Urography in 40 of these patients showed a structural anomaly of the renal tract in eight. Here we describe another child with selective malabsorption of vitamin B,1 in whom there was no proteinuria and in whom no renal tract anomaly was shown on urography. Case report A 3 2-year-old boy whose health had been normal until the age of 2 years presented with an 18-month history of difficult behaviour and tiring easily. He had had no abnormality of his faeces, and there was no history of con-sanguinity. His weight was 15 kg (between 25th and 50th percentile for his age). He was pale and irritable. There was no enlargement of the liver or spleen. The results of preliminary investigations are shown in the table. The blood film showed anisopoikilocytosis, with oval macrocytes and neutrophil hyper-segmentation. A bone marrow aspirate showed definite megaloblastic erythropoiesis and numerous giant metamyelocytes. There was increased stainable iron in the reticuloendothelial cells and in the erythroblasts. A urine sample taken without previous valine loading disclosed a methylmalonic acid concentration of 1-5 g/l. Consequently, daily physiological doses of one microgram hydroxocobalamin were given, and a reticulocyte response of 26 was noted on the fourth day. The one-hour gastric secretion after penta-gastrin stimulation (6 ,tg/kg) was 30 ml, with pH 1 0, free acid 9 mmol (mEq) 1, total acid 16 4 mmol(mEq),ll, intrinsic factor activity before pentagastrin 17 U/ml, after pentagastrin 36 U,ml. The Schilling test showed impaired vitamin B1.2 absorption with less than I excretion of a lug g 51Co-labelled oral dose in 24 hours, and this was uncorrected by the administration of an active preparation of hog intrinsic factor. A 24-hour urine collection showed no protein even after concentration and no abnormality on amino-acid chromatography. The results of the following investigations were normal: chest x-ray film, intravenous pyelogram, barium follow-through; serum calcium and phosphate, magnesium, and vitamin A concentrations; pro-thrombin time; urinary indican; and tests for ova and cysts in the faeces. …