Mucopolysaccharidosis type IIIC diagnosed at the age of 12 years: Why was the disease diagnosed so late?
Institute of Clinical Sciences, Maria Skłodowska-Curie Medical Academy, Warsaw, Poland
Third Department of Pediatrics, Center of Postgraduate Medical Education, Dziekanów Leśny, Poland
Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
Department of Medical Genetics, Medical University of Warsaw, Poland
Pediatr Endocrinol Diabetes Metab 2026; 32 (3):
Mucopolysaccharidoses (MPS) are a group of inherited metabolic diseases associated with impaired lysosomal degradation of glycosaminoglycans. The aim of this manuscript is to report a case of a patient with mucopolysaccharidosis type IIIC (MPS IIIC) diagnosed at 12 years of age – to raise awareness among pediatricians, pediatric neurologists, and endocrinologists about the possible misdiagnosis. The patient was initially diagnosed with autism spectrum disorder and hyperactivity with normal motor development. During follow-up, psychomotor regression with moderate intellectual disability was observed. The patient was referred for further metabolic work-up only after the results of molecular analysis suggesting MPS IIIC. The final diagnosis was established based on clinical, biochemical, and molecular analyses.
Keywords
mucopolysaccharidosis, autism spectrum disorder, psychomotor regression, glycosaminoglycan electrophoresis
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