Purine salvage deficiencies Flashcards
What are the two purine salvage deficiencies?
ADA deficiency
Lesch-Nyhan syndrome
Mode of inheritance: ADA deficiency
AR
What does HGPRT catalyze?
Guanine —> GMP
Hypoxanthine —> IMP
What causes ADA deficiency?
Too much ATP and dATP, which causes feedback inhibition of ribonucleotide reductase, thereby inhibiting pyridimidine synthesis, which decreases pool of rapidly-dividing T cells and B cells
What would be elevated in the blood of a kid with Lesch-Nyhan syndrome?
Uric acid
Mode of inheritance: Lesch-Nyhan syndrome
X-linked recessive
Which drug is activated by HGPRT?
6-MP
(inhibits PRPP —> IMP in purine synthesis)
What does xanthine oxidase catalyze?
Hypoxanthine –> xanthine
Xanthine –> uric acid
What are the symptoms of Lesch-Nyhan syndrome?
Hyperuricemia
Gout
Pissed (agitation, self-mutilation)
Retardation
dysTonia
Which drug produces the same deficiency as ADA deficiency?
Hydroxyurea
(Both cause inhibition of ribonucleotide reductase)
What does ADA catalyze?
Adenosine —> inosine
What causes Lesch-Nyhan syndrome?
HGPRT deficiency, so can’t generate IMP or GMP
How is Lesch-Nyhan syndrome treated?
Allopurinol or febuxostat
ADA deficiency is the primary cause of:
SCID
Which drug in inactivated by XO (and TMPT)?
6-MP
(inhibits PRPP —> IMP in purine synthesis)
