Linked from
The 5 pages that link to Hypoxanthine, each with the reason it gives.
AdenineRelated: It is a related purine base, but it is not one of DNA’s standard bases.
Xanthine oxidaseRelated: It is the enzyme’s first substrate in the pathway to uric acid.
XanthineRelated: Its oxidation is the step immediately before xanthine formation.
InosineBroader topic: It is the base attached to ribose in inosine.