USMLE

Phenylketonuria (PKU)

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Metabolic Disorders
  1. Albinism
  2. Pyruvate Dehydrogenase Deficiency
  3. Pyruvate Kinase Deficiency
  4. G6PD Deficiency
  5. Essential Fructosuria
  6. Hereditary Fructose Intolerance
  7. Galactosemia
  8. Galactokinase Deficiency
  9. Lactase Deficiency
  10. Ornithine Transcarbamylase Deficiency
  11. Phenylketonuria (PKU)
  12. Maple Syrup Urine Disease
  13. Alkaptonuria
  14. Homocystinuria
  15. Cystinuria
  16. Propionic Acidemia
  17. Lesch-Nyhan Syndrome
  18. Systemic Primary Carnitine Deficiency
  19. MCAD Deficiency

Phenylketonuria (PKU) is an autosomal recessive disorder caused by defects in metabolizing phenylalanine to tyrosine (See Catecholamine Synthesis).

Excess phenylalanine is converted into phenylketones in the urine, giving rise to the name, phenylketonuria. PKU can be caused by defects in phenylalanine hydroxylase or its BH4 cofactor. Since tyrosine cannot be produced from phenylalanine, tyrosine becomes essential in the diet.

Clinical features include seizures and cognitive delays. Growth retardation and failure to thrive is observed, and on exam, patients will often have a light or fair complexion, eczema, and a characteristic musty body odor. Diagnosis is delayed 2-3 days after birth since infants are normal at birth due to the presence of maternal enzymes.

Find this Phenylketonuria mnemonic and more mnemonics for Metabolic Disorders among Pixorize's visual mnemonics for the USMLE Step 1 and NBME Shelf Exams.