Type I<unk>  can be caused by a deficiency of xanthine oxidase, which is an enzyme necessary for converting xanthine to uric acid. Type II<unk>  and molybdenum cofactor deficiency lack one or two other enzyme activities in addition to xanthine oxidase.
Xanthinuria
Lipiduria
Cystinuria
Iminoglycinuria
Sialuria
Pentosuria
Uricosuria
Hyperuricosuria