• Insight to Mucopolysaccharidosis type II (Hunter syndrome)
  • Hanieh Askari,1 Saman Hakimian,2,*
    1. Biotechnology student , Kashan University
    2. M.sc student of Microbiology Islamic Azad University Central Tehran Branch, Iran, Tehran


  • Introduction: Mucopolysaccharidosis type II (MPS II; also known as Hunter syndrome) is a rare lysosomal storage disease. The disease is caused by deficiency of the lysosomal enzyme iduronate-2-sulfatase (I2S), which catalyzes the hydrolysis of 2-sulfate groups on dermatan sulfate and heparan sulfate. Deficiency of I2S enzyme activity in patients with MPS II leads to progressive lysosomal storage of GAGs in the liver, spleen, heart, bones, joints, and respiratory tract. MPS II has two clinical forms: neuronopathic, with CNS involvement, and nonneuronopathic, without involvement of the CNS.
  • Methods: The disease can be transmitted through the mother, who is the carrier of the mutated gene. The syndrome occurs primarily in male children aged between two and five years, while female children are usually not affected, but a case has been reported in a heterozygous female. Early diagnosis is of great importance for the treatment of Hunter syndrome. Diagnosis of MPS II involves assessment of clinical features, biochemical parameters, and molecular characteristics.
  • Results: macrocephalic head, coarse facial features, enlarged liver and spleen, lower level of I2S, aortic insufficiency, an enlarged left half of the heart and hearing loss are the symptoms of MPSII.
  • Conclusion: The current treatments are gene therapy, bone marrow transplantation, Hematopoietic stem cell transplantation, Elaprase which is life-long therapy contains the active substance idursulfase (Enzyme replacement therapy) and Substrate reduction therapy.
  • Keywords: Mucopolysaccharidosis type II , Hunter syndrome , MPS II , Enzyme replacement therapy , I2S