title: Tetrahydrobiopterin metabolism in Down's syndrome and in non-Down's syndrome mental retardation.
mesh_terms: D000328:Adult; D000368:Aged; D001708:Biopterins / Q000031:analogs & derivatives / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D004314:Down Syndrome / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000097:blood / Q000209:etiology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010649:Phenylalanine / Q000097:blood; D011621:Pteridines / Q000378:metabolism*
chemical_list: D011621:Pteridines; D001708:Biopterins; D010649:Phenylalanine; C017226:7,8-dihydrobiopterin; C003402:sapropterin