The sequence variant c.295T>Cin exon 3 changes tyrosine in position 99 to histidine (p.Tyr99His). Studies in transfected cells show that p.His99 is inactive, but processed and localized to the lysosomes. p.Tyr99 is located in the dimer interface and 3d-modelling indicates that the substitution changes the dimerization properties of the enzyme which may make the enzyme more susceptible to degradation.