However, if the degree of BBB damage in Sanfilippo IIIB patients is similar to that observed in other MPS III subtypes59 or if it bears any resemblance to the Naglu KO mouse model, it would be important to understand the clinical aspects of whether and how BBB compromise in MPS IIIB affects disease pathogenesis and progression. The gene discussed is NAGLU; the disease is mucopolysaccharidosis type 3B.