Survey of Patients With Sanfilippo Type a (MPS IIIA ) Disease Diagnosed by the MPS Brazil Network

ABSTRACT Mucopolysaccharidosis IIIA (MPS IIIA) is an autosomal recessive lysosomal disease caused by the deficiency of N‐sulfoglucosamine sulfohydrolase (SGSH), due to biallelic mutations in the SGSH gene. We conducted a retrospective study utilizing data from MPS IIIA patients born from 1983 to 2024 diagnosed by the MPS Brazil Network. Sixty‐eight patients with MPS IIIA were included. The age at diagnosis was 7.3 ± 4.7 (y), a delay of almost 4y compared to the age of onset of symptoms (3.8 ± 1.5). Developmental delay (42%), facial abnormalities (32%), and joint restriction (12%) were the first described symptoms. Behavior problems were present in most cases. Low SGSH activity and a high urinary glycosaminoglycans (uGAGs) concentration were observed, as expected. A positive correlation between age at diagnosis and urinary GAGs concentration was detected ( p  < 0.05). Joint restriction was described in most patients, which is not commonly described in this condition. We hope that the present data can help to reduce the age at diagnosis, helping to introduce the palliative care measures available and to provide a more precise genetic counseling.