Learn / FMK
Every FMK condition
299 diseases, deficiencies, toxicities and drug mechanisms harvested from every FMK deck — the ones sprinkled through a single bullet as much as the ones with their own slide. Pick what you're given and what you have to name, or let it cycle; distractors come from the same category so you have to discriminate (hypoketotic vs. ketotic hypoglycemia, which GSD, which urea-cycle enzyme…). Every answer shows the whole card with the lecture and slide.
Nucleotide · FMK 08.1
Purine nucleoside phosphorylase (PNP) deficiency Autosomal recessive
Defect / target: Purine nucleoside phosphorylase (removes the sugar from purine nucleosides to yield the free base)
Mechanism: Accumulating purine nucleosides (notably deoxyguanosine -> dGTP) are toxic to T lymphocytes, causing a milder, predominantly T-cell immunodeficiency that spares B cells more than ADA deficiency.
↑ Accumulates: Purine nucleosides (inosine, guanosine, deoxyguanosine/dGTP)· ↓ Deficient: T lymphocytes (B cells relatively spared)
Presentation: Recurrent infections with predominantly T-cell immunodeficiency; milder than ADA deficiency
Labs: Low T-cell count; low serum uric acid
Treatment: Supportive care, hematopoietic stem cell transplant
Compare: ADA = T + B + NK loss (severe); PNP = predominantly T-cell loss (milder)
Learn the mechanism: Purine degradation & uric acid →
FMK 08.1 Nucleic Acid Metabolism · slide 17, 28