SGSH and mucopolysaccharidosis type 3: This is the case of Sanfilippo syndrome, caused by four different genetic defects affecting lysosomal heparan sulfate degradation, each one defining a different disease subtype A, B, C and D. In this regard, Sanfilippo A represents 60% of all diagnosed cases and is caused by a deficiency of the heparan N‐sulfatase enzyme, also known as N‐sulfoglucosamine sulfohydrolase (SGSH).