Abstract: (11201 Views)
Introduction: Megaloblasc anemia is an uncommon problem in childhood most frequently associated with vitamin deficiency or gastrointesnal disease. The common causes of megaloblasc anemia are vitamin B12 (cobalamin) deficiency and folic acid deficiency. Familial selecve malabsorpon of vitamin B12 associated with proteinuria firstly was described by Imerslund (1960) and Grasbeck et al (1960) (Imerslund-Grasbeck syndrome).1,2 About 300 paents have been published worldwide, with new paents mostly appearing in eastern Mediterranean countries. However, lots of paents may be misdiagnosed.3 Imerslund-Grasbeck syndrome (IGS), an autosomal recessive disease, is associated with megaloblasc anemia and proteinuria. The diagnosis should be considered when three typical features (macrocyc anemia, decreased serum B12 level, and proteinuria) are present. Symptoms may appear from the 4th month of age (not immediately a!er birth as in transcobalamin deficiency) up to several years later. The cause is a defect in the receptor of the vitamin B12-intrinsic factor complex on the ileal enterocytes. In most cases, the molecular basis of the selecve malabsorpon and proteinuria involves a mutaon in one of two genes, cubilin (CUBN) on chromosome 10 or amnionless (AMN) on chromosome 14. Both proteins are components of the intesnal receptor for the vitamin B12- intrinsic factor complex and the receptor mediang the tubular reabsorpon of protein from intraglomerular filtrate. Management includes life-long vitamin B12 injecons, resulng in a long healthy life. Nevertheless, proteinuria persists. To diagnose the disease, it is important to be aware that cobalamin deficiency affects enterocyte funcon therefore, all tests suggesng general and cobalamin malabsorpon should be repeated a!er resolving the deficiency.3
:
Original Article |
Subject:
Pediatric Hematology & Oncology Received: 2012/01/10 | Published: 2010/10/15