Hurler Syndrome - Genetics

Genetics

Children born to an MPS I parent carry a defective IDUA gene, which has been mapped to the 4p16.3 site on chromosome 4. The gene is named IDUA because of its iduronidase enzyme protein product. As of 2001, 52 different mutations in the IDUA gene have been shown to cause Hurler syndrome.

Because Hurler syndrome is an autosomal recessive disorder, affected persons have two non-working copies of the IDUA gene. If someone is born with one normal and one defective copy of the gene (s)he is called a carrier and will produce less α-L-iduronidase than an individual with two normal copies of the gene. The slightly reduced production of the enzyme in carriers, however, remains sufficient for normal function and the person should not show any symptoms of the disease.