Genotype-phenotype studies in a large cohort of Brazilian patients with Hunter syndrome

Am J Med Genet C Semin Med Genet. 2021 Sep;187(3):349-356. doi: 10.1002/ajmg.c.31915. Epub 2021 May 7.


Mucopolysaccharidosis type II (MPS II) is an X-linked inherited disease caused by pathogenic variants in the IDS gene, leading to deficiency of the lysosomal enzyme iduronate-2-sulfatase and consequent widespread storage of glycosaminoglycans, leading to several clinical consequences, with progressive manifestations which most times includes cognitive decline. MPS II has wide allelic and clinical heterogeneity and a complex genotype-phenotype correlation. We evaluated data from 501 Brazilian patients diagnosed with MPS II from 1982 to 2020. We genotyped 280 of these patients (55.9%), which were assigned to 206 different families. Point mutations were present in 70% of our patients, being missense variants the most frequent. We correlated the IDS pathogenic variants identified with the phenotype (neuronophatic or non-neuronopathic). Except for two half-brothers, there was no discordance in the genotype-phenotype correlation among family members, nor among MPS II patients from different families with the same single base-pair substitution variant. Mothers were carriers in 82.0% of the cases. This comprehensive study of the molecular profile of the MPS II cases in Brazil sheds light on the genotype-phenotype correlation and helps the better understanding of the disease and the prediction of its clinical course, enabling the provision of a more refined genetic counseling to the affected families.

Keywords: Hunter syndrome; IDS gene; iduronate-2-sulfatase; lysosomal storage diseases; mucopolysaccharidosis type II.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brazil
  • Genotype
  • Humans
  • Male
  • Mucopolysaccharidosis II* / genetics
  • Mutation
  • Phenotype