Case Report: Compound heterozygous mutations in the IDUA gene causing mucopolysaccharidosis type I with uterine developmental abnormality

TL;DR

A 13-year-old girl with MPS I caused by IDUA gene mutations also had a uterine abnormality, suggesting a possible link to reproductive system issues.

Contribution

This case report expands the known phenotypic spectrum of MPS I to include uterine developmental abnormalities.

Findings

Compound heterozygous IDUA gene mutations were identified in a patient with MPS I-S.

The patient exhibited uterine developmental abnormalities alongside typical MPS I symptoms.

The case suggests a potential association between MPS I and reproductive system developmental issues.

Abstract

Mucopolysaccharidosis (MPS) represents a group of rare inherited metabolic disorders characterized by abnormal accumulation of glycosaminoglycans (GAGs) due to deficiencies of lysosomal enzymes. Mucopolysaccharidosis type I (MPS I) is caused by biallelic pathogenic variants in the IDUA gene and is inherited in an autosomal recessive pattern. The IDUA gene is located on chromosome 4p16.3 and encodes the lysosomal enzyme α-L-iduronidase, which plays a critical role in the degradation of GAGs, particularly dermatan sulfate and heparan sulfate. Reduced or absent IDUA enzymatic activity leads to the progressive accumulation of undegraded substrates within lysosomes, resulting in multisystem organ involvement. Based on clinical severity, MPS I is traditionally classified into three phenotypic subtypes: the severe form (Hurler syndrome), the intermediate form (Hurler–Scheie syndrome), and the attenuated form (Scheie syndrome, MPS I-S). This report describes a 13-year-old female patient in whom compound heterozygous pathogenic variants in the IDUA gene were identified by genetic testing, and whose clinical manifestations were consistent with the MPS I-S. In addition to typical skeletal and joint abnormalities, the patient also presented with uterine developmental abnormality. Currently, there is no definitive evidence supporting a direct causal relationship between MPS I and uterine developmental abnormalities; however, this case suggests a potential association between MPS I and reproductive system developmental abnormalities. This case may help further expand the phenotypic spectrum of MPS I and enhance clinical awareness of its multisystem involvement.

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