<unk>  has an autosomal recessive pattern of inheritance. Children with<unk>  carry two defective copies of the IDUA gene, which has been mapped to the 4p16.3 site on chromosome 4. This is the gene which encodes for the protein iduronidase. All patients with subtypes of MPS I have mutations in the same gene, leading to deficiencies of the same enzyme. However, patients with<unk>  have a greater level of iduronidase activity than patients with Hurler<unk> . Because<unk>  is an autosomal recessive disorder, affected persons have two nonworking copies of the gene. A person born with one normal copy and one defective copy is called a carrier. They will produce less α-L-iduronidase than an individual with two normal copies of the gene. The reduced production of the enzyme in carriers, however, remains sufficient for normal function; the person should not show any symptoms of the disease.
Scheie syndrome
Hunter syndrome
Gerstmann–Sträussler–Scheinker syndrome
Mucopolysaccharidosis type I
Gerstmann syndrome
Mucopolysaccharidosis
Pallister–Killian syndrome
Hurler syndrome