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

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 <i>IDUA</i> gene and is inherited in an autosomal recessive pattern. The <i>IDUA</i> gene is located on chromosome 4p16.3 and encodes the lysosomal enzyme <i>α</i>-L-iduronidase, which plays a critical role in the degradation of GAGs, particularly dermatan sulfate and heparan sulfate. Reduced or absent <i>IDUA</i> 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 <i>IDUA</i> 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.