Defective IDUA does not hydrolyse the unsulfated alpha-L-iduronosidic link in DS

Stable Identifier
Reaction [transition]
Homo sapiens
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Absence of alpha-L-iduronidase (IDUA, MIM:252800), the enzyme responsible for the removal of non-reducing terminal alpha-L-iduronide (Lido) residues during the lysosomal degradation of heparan sulphate (HS) and dermatan sulfate (DS) is the cause of MPS I disorders (MIM:607014). The nonsense mutations, W402X and Q70X and the rarer P553R account for approximately 50% of all MPS I alleles in patients with predominantly European origins (Scott et al. 1992, Bunge et al. 1994, Scott et al. 1992b). There are, however, considerable differences in the frequency of these mutations in patients from Norway and Finland when compared with other Eurpoean countries. In Scandinavia, W402X and Q70X account for 17% and 62% of the MPSI alleles, respectively, while in the other European countries W402X is about 2.5 times more frequent (48%) than Q70X (19%).
Literature References
PubMed ID Title Journal Year
1301941 alpha-L-iduronidase mutations (Q70X and P533R) associate with a severe Hurler phenotype

Hopwood, JJ, Morris, CP, Nelson, PV, Scott, HS, Brooks, DA, Litjens, T

Hum Mutat 1992
1301196 A common mutation for mucopolysaccharidosis type I associated with a severe Hurler syndrome phenotype

Hopwood, JJ, Morris, CP, Scott, HS, Litjens, T

Hum Mutat 1992
7951228 Mucopolysaccharidosis type I: identification of 8 novel mutations and determination of the frequency of the two common alpha-L-iduronidase mutations (W402X and Q70X) among European patients

Hopwood, JJ, Morris, CP, Zuther, C, Steglich, C, Bunge, S, Scott, HS, Beck, M, Gal, A, Schwinger, E, Kleijer, WJ

Hum Mol Genet 1994
Catalyst Activity

L-iduronidase activity of IDUA mutants [lysosomal lumen]

Normal reaction
Functional status

Loss of function of IDUA mutants [lysosomal lumen]

Name Identifier Synonyms
mucopolysaccharidosis I DOID:12802 Lipochondrodystrophy, Mucopolysaccharidosis, type 1, Mucopolysaccharidosis, MPS-I (disorder), Mucopolysaccharidosis type I [Ambiguous], iduronidase deficiency disease
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