mucopolysaccharidosis type iii b (sanfilippob) in a dizygotic twin: a case report

the mucopolysaccharidoses are a clinically and genetically heterogenous group of lysosomal storage diseases caused by defects in different enzymes for mucopolysaccharid degradation (glycosaminoglycans). except for mucopolysaccharide storage disease type ii (hunter disease), all are transmitted through an autosomal recessive mode of inheritanceinheritance. clinical feature of these metabolic disorders result from accumulation of mucopolysaccharides in various organs. these disorders have been classified based on clinical manifestations and enzyme defects. this poster presentation is a case report of a dizygotic twin, a boy and a girl of a second cousin couple, with short stature, scoliosis and characteristic bony changes (dysostosis multiplex), progressive and profound mental retardation and coarse faces, hepatosplenomegaly in both and also umbilical hernia in the girl. both of them have a conductive hearing loss. urinary mucopolysaccharide was positive and biochemical analysis showed heparan sulfate. therefore, we requested the evaluation of heparan sulfamidase, alpha–n-acetyl hexosaminidase, n–acetyl glucosamine 6 sulfatase and acetyl coa alpha glucosaminide n acetyl transferase activity in their leukocytes that showed very low activity of alpha –n – acetyl hexosaminidase (glucosaminidase) and confirmed the diagnosis of sanfilippo (mps iii) b. their mother is 5 weeks pregnant now and we have planned for cvs and enzyme assay of her fetus in the 12th week of gestation.