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.
Amino acid · FMK 07.2
Phenylketonuria (classic PKU) Autosomal recessive
Defect / target: Phenylalanine hydroxylase (PAH) deficiency (~98%; BH₄-requiring enzyme converting Phe → Tyr)
Mechanism: Phenylalanine cannot be hydroxylated to tyrosine, so it accumulates and is shunted to phenylketones while tyrosine becomes conditionally essential; excess Phe also competitively inhibits tyrosinase, reducing melanin.
↑ Accumulates: Phenylalanine; phenylpyruvate, phenylacetate, phenyllactate in urine· ↓ Deficient: Tyrosine; melanin (secondary tyrosinase inhibition)
Presentation: No neonatal symptoms; untreated: severe intellectual disability, developmental delay, microcephaly, seizures; fair hair, light skin, blue eyes; musty urine odor; 1:15,000, most common inborn error of amino acid metabolism
Labs: Newborn screening 24–48 h after protein feeding begins; ↑ plasma Phe; phenylketones in urine
Treatment: Dietary Phe restriction started within 7–10 days of life and continued lifelong; tyrosine supplementation
Musty odor; diet fixes classic PKU but not DHPR deficiency
Learn the mechanism: Catecholamines, serotonin & the tyrosine tree →
FMK 07.2 Amino Acid Metabolism II · slide 07.2: 2, 5, 6, 7, 12, 15; 07.1: 25, 26