Patients with Lesch-Nyhan syndrome have a shortened life expectancy..

Patients with Lesch-Nyhan syndrome have a shortened life expectancy
(a) What is the enzyme defect?
(b) What is the cause of their reduced life expectancy?
(a)How is dietary folic acid activated?
(b)The single carbon unit comes from serine and there are 4 forms of folic acid coenzymes (ie 4 ways in which folic acid transfers 1-C units in biochemical reactions). How are they interconverted, one to another form?
(c)In the transfer of a single carbon atom to form dTMP from dUMP, the folic acid is converted to dihydrofolate. How is it reactivated to tetrahydrofolate?
A  little bit complex....Thanks