USMLE

Hereditary Fructose Intolerance

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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

Hereditary Fructose Intolerance is an autosomal recessive disease caused by a lack of aldolase B, which leads to the accumulation of fructose-1-phosphate (See Fructose Metabolism - coming soon!).

Fructose-1-phosphate binds free phosphate, thereby acting as a phosphate sink and depleting intracellular stores. The build-up of unmetabolized fructose leads to its presence in the urine, which presents as a reducing substance (fructose sugar) in the urine, despite a negative urine dipstick (no glucose in urine).

Patients become symptomatic only after consuming fructose, so infants often present after consuming fruit, juice, or honey. Symptoms include vomiting, hypoglycemia, jaundice, and eventual liver cirrhosis. Prognosis is poor in comparison to Essential Fructosuria.

Find Hereditary Fructose Intolerance and other Metabolic Disorders among Pixorize's visual mnemonics for the USMLE Step 1 and NBME Exams.