Hurler Syndrome: A Mini Review

Abstract

Hurler syndrome is a lysosomal  storage disorder also  known as mucopolysaccharidosis type I. There are  two  other,  less  severe  types  of mucopolysaccharidosis  type  I,  the  Hurler -Scheie  syndrome  and the Scheie syndrome. Hurler syndrome is a rare autosomal recessive disorder with a prevalence of 1 in 200,000 and a life expectancy of less than 10 years. It is caused by a defective gene for the enzyme α-L   iduronidase.   The   resulting   enzyme   deficiency   leads   to   the   progressive   accumulation   of glycosaminoglycans  namely,  dermatansulphate  and  heparan  sulfate  in  multiple  tissues  in  the  body, causing abnormally thick mucus secretion in the respiratoryand digestive tracts as well as abnormal enlargement,  thickening,  and  malfunction  of  many  tissues  and  organs.  The  symptoms  include intellectual  disability,  characteristic  musculoskeletal  manifestations  as  well  as  cardiac  disease  and neurological  impairments.  Some  of  the  symptoms  appear  during  the  first  twelve  months  after  birth and vary from patient to patient. However, the lack of a reliable prognostic biomarker makes it more difficult to make a treatment decision for newborns diagnosed through screening,making the timing of  diagnosis  and  treatment  initiation  very  important.  Treatments  found  to  improve  life  expectancy include  Enzyme  Replacement  Therapy  and HematopoieticStem  Cell  Transplantation.  Several  surgical procedures  can  also  be  performed  to  mitigate  some  ofthe  symptoms  of  the  syndrome. Today,  gene therapy  is  considered  a  very  promising  method  while  transplantations  of  the  bone  marrow  and  the umbilicus are close to becoming crucial for Hurler’s syndrome treatment