Abstract
BACKGROUND: Sanfilippo A Syndrome (mucopolysaccharidosis [MPS] IIIA), an inherited lysosomal storage disorder, is mainly characterized by central nervous system degeneration that is characterized by neurocognitive decline and typically results in early death. Some Sanfilippo A Syndrome patients have heart diseases, which are typically not severe. Moreover, there have been no reported cases of patients with Sanfilippo A Syndrome who also have sick sinus syndrome (SSS). CASE PRESENTATION: This case describes a 44-year-old woman with a history of a preliminary clinical diagnosis of MPS. She had a mild respiratory infection and promptly recovered. Nevertheless, upon arriving at our hospital, she was found to have severe and persistent bradycardia. We conducted a detailed examination of her. The electrocardiogram monitoring revealed frequent sinus arrest with the maximum R-R interval of 5.47 s. Brain CT scan and cranial MRI showed global brain atrophy and ventricular enlargement. The urinary glycosaminoglycans level was 3.88 ± 0.11 ng/ml. The level of N - sulfoglucosamine sulfohydrolase (SGSH) enzyme activity was significantly reduced, and gene sequencing identified a heterozygous G > A change in the SGSH gene at nucleotide c.1063G > A. The diagnosis of SSS co-occurring with Sanfilippo A Syndrome was established. CONCLUSIONS: This is the first reported case of SSS in an adult with Sanfilippo A Syndrome. This case suggests SSS may be a potential associated feature of Sanfilippo A Syndrome. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12883-025-04354-7.