Favorites 1 Flashcards
(47 cards)
cAMP signaling pathway (Gs)
ACTH, FSH, LH, TSH, PTH, glucagon
IP₃/DAG pathway (Gq)
GnRH, TRH, oxytocin, angiotensin II (GATO)
MAP kinase pathway (RTKs)
Insulin, IGF-1, FGF, PDGF (PIFI) map pifi
JAK-STAT pathway
GH, prolactin, EPO, cytokines (IL-2, IL-6)
GEProCy
G6PD deficiency
hemolysis after fava beans or sulfa drugs
Sickle cell anemia
glutamic acid → valine (missense)
(1er remplace 2ieme)
Lead poisoning
inhibits ALA dehydratase & ferrochelatase
Basophilic stippling
ALA: aminolevulinate
Crigler-Najjar syndrome
Type 1: absent UDP-glucuronosyltransferase
High risk of kernicterus
Does not respond to phenobarbital
Type 2: partial. Respond to phenobarbital
I-cell disease
defective mannose-6-P tagging in GolgI
Defect in N-acetylglucosaminyl-1-phosphotransferase
Lysosomes become cluttered with undigested material (inclusions)
Caused by defective phosphotransferase enzyme
* Failure to tag lysosomal enzymes with mannose-6-phosphate
* Enzymes get secreted outside the cell instead of delivered to lysosomes
Chediak-HiGashi syndrome
Giant Granules in neutrophils
Caused by a defect in lysosomal trafficking regulator gene (LYST) →
* Microtubule dysfunction
* Failure of lysosomes to fuse properly with phaGosomes
Results in:
* Inefficient killinG of pathoGens
* Accumulation of Giant Granules inside cells
Mnemonic: “PLAIN”
* Progressive neurodegeneration (peripheral neuropathy, ataxia)
* Lymphohistiocytosis (uncontrolled lymphocyte/macrophage activation)
* Albinism (partial, due to defective melanosome transport)
* Infections (recurrent pyogenic infections, especially Staph and Strep)
* Neutropenia and pancytopenia (due to marrow involvement)
Kartagener syndrome
dynein arm defect → infertility + sinusitis
A subset of primary ciliary dyskinesia (PCD) characterized by a triad of:
• Situs inversus (including dextrocardia — heart on right side)
• Chronic sinusitis
• Bronchiectasis
Defective dynein arms → immotile cilia
Autosomal recessive
• Gene mutations: Often involve DNAI1 or DNAH5 genes (but many genes possible
Conductive hearing loss from recurrent otitis media
Low nasal nitric oxide levels (screening test — very high-yield)
Rapid-Fire Step 1 Tips:
• Triad: Situs inversus + chronic sinusitis + bronchiectasis = Think Kartagener immediately.
• Low nasal nitric oxide is a classic Step 1 association.
• Look for male infertility clue in vignettes.
• Defective dynein arms is the molecular basis — memorize this!
Achondroplasia
FGFR3 mutation (AD)
Neurofibromatosis type I
Mutation in NF1 gene on chromosome 17.
• Neurofibromin (a tumor suppressor that inhibits Ras — a proto-oncogene).
• Loss of neurofibromin → Ras overactivation → uncontrolled cell growth.
• Tumor suppressor gene malfunction (NOT a proto-oncogene mutation directly).
Mnemonic : Café SPoT
Feature
Details
Café-au-lait spots
Hyperpigmented macules, flat, light-brown.
Skin neurofibromas
Benign nerve sheath tumors; soft, fleshy nodules on skin.
Pheochromocytoma
Catecholamine-secreting tumor (hypertension, palpitations).
Optic glioma
Can lead to vision loss.
Tibial pseudoarthrosis
Bowing of the legs, bone dysplasia.
cafe-au-lait spots + Lisch nodules
100% penetrance, but variable expressivity.
Marfan syndrome
Autosomal dominant connective tissue disorder caused by mutations in FBN1, the gene encoding fibrillin-1, a glycoprotein important for the formation of elastic fibers.
FBN1 mutation (fibrillin)
Mutation: FBN1 gene on chromosome 15
Associated pathway: ↑ TGF-β signaling due to defective sequestration by fibrillin → contributes to the disease.
Clinic
arachnodactyly = “spider fingers”)
pectus excavatum = sunken chest, or pectus carinatum = protruding chest)
Hypermobile joints (joint laxity)
• Scoliosis
2. Ocular: • Ectopia lentis (upward and temporal lens dislocation) — extremely high-yield! • Early cataracts 3. Cardiovascular (most dangerous, most common cause of death): • Aortic root dilation → aortic aneurysm, aortic regurgitation • Aortic dissection (especially ascending aorta — Stanford type A dissection) • Mitral valve prolapse (MVP)
Homocystinuria = Downward and inward (“Homo goes low”)
• Homocystinuria can mimic Marfan but has:
• Intellectual disability
• Thrombosis
• High methionine levels
Pseudohypoparathyroidism
resistance to PTH, short 4th/5th metacarpals
Vitamin D activation
1α-hydroxylase in kidney
Addison disease
↑ ACTH, hyperpigmentation, hypotension
Waterhouse-Friderichsen syndrome
N. meningitidis + adrenal hemorrhage
Hashimoto thyroiditis
anti-TPO antibodies, Hürthle cells
Graves disease
TSI antibodies, pretibial myxedema
MEN syndromes
RET, MEN1 gene associations
Nephrogenic DI
lithium side effect
Rickets vs. osteomalacia
defective bone mineralization
Osteogenesis imperfecta
COL1A1 defect, multiple fractures, blue sclerae
