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
Adenosine deaminase (ADA) deficiency — SCID Autosomal recessive
Defect / target: Adenosine deaminase (purine degradation: adenosine -> inosine)
Mechanism: Without ADA, adenosine and deoxyadenosine accumulate and are converted to dATP, which allosterically inhibits ribonucleotide reductase, halting synthesis of ALL dNTPs and causing developmental arrest and apoptosis of lymphocyte precursors (lymphocytes have the highest ADA activity of any cell type).
↑ Accumulates: Adenosine, deoxyadenosine, dATP· ↓ Deficient: All deoxyribonucleotides (dNTPs) in lymphocytes; T, B, and NK cells
Presentation: Severe combined immunodeficiency: recurrent infections (e.g., third pneumonia at 4 months), absent thymic shadow on chest X-ray, failure to thrive; fatal by ~age 2 if untreated
Labs: Critically low absolute lymphocyte count (T, B, and NK cells depleted); elevated dATP
Treatment: Enzyme replacement (PEG-ADA), hematopoietic stem cell transplant, gene therapy
Baby Sophia — a defect in recycling a nucleotide breakdown product wipes out the immune system. ADA deficiency = more common and more severe than PNP deficiency (T + B + NK loss).
Learn the mechanism: Purine degradation & uric acid →
FMK 08.1 Nucleic Acid Metabolism · slide 2, 17, 28, 29