Adolescent Child Child, Preschool Clinical findings DNA Mutational Analysis Founder Effect Genes Haplotypes Humans Hydrolases Mucopolysaccharidosis III Mucopolysaccharidosis IIIA Mutation Mutation 1091delC Mutation detection Mutation frequencies Polymorphism, Single-Stranded Conformational SSCP Sanfilippo A Sequence Deletion Spain Sulfamidase allele amidase article catabolism enzyme deficiency gene frequency gene location gene mutation