Mucopolysaccharidosis type III (Sanfilippo syndrome): a rare case report

Background. Mucopolysaccharidosis type III (MPS III), or Sanfilippo syndrome, is a rare autosomal recessive lysosomal storage disorder caused by deficiencies in enzymes involved in the degradation of heparan sulfate. It is characterized by progressive neurodegeneration, behavioral disturbances, and mild skeletal abnormalities, leading to severe cognitive impairment and shortened life expectancy. Case presentation. We present the case of a 4-year-old girl diagnosed with MPS IIIA, who initially presented with speech delay, hyperactivity, and developmental regression. Physical examination revealed coarse facial features, hepatosplenomegaly, and joint stiffness. Laboratory analysis showed elevated urinary glycosaminoglycans, and genetic testing confirmed a pathogenic mutation in the SGSH gene. Magnetic resonance imaging (MRI) revealed diffuse cerebral atrophy, consistent with neurodegenerative changes seen in MPS III. Discussion. Sanfilippo syndrome remains a diagnostic challenge due to its overlapping features with autism spectrum disorder (ASD) and other neurodevelopmental disorders. Early recognition and genetic confirmation are crucial for accurate diagnosis and supportive management. Currently, no disease-modifying treatment exists, but ongoing clinical trials in gene therapy and substrate reduction therapy offer promising future interventions. Conclusion. This case highlights the importance of early genetic testing and multidisciplinary care for children with suspected MPS III. Advances in molecular diagnostics and potential emerging therapies may improve disease outcomes and quality of life. Increased awareness among pediatricians, neurologists, and genetic specialists is essential for early detection and timely intervention.