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Biochemistry Diseases

Subject : health-sciences
Instructions:
  • Answer 50 questions in 15 minutes.
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  • Match each statement with the correct term.
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This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Trisomy 18 (E=election age) - 1:8000. Severe MR - rockerbottom feet - congenital heart disease. Vs Patau's: micrognathia - low - set ears - clenched hands - prominent occiput. Death w/in 1 yr


2. Glucose -6- phosphatase deficiency (type I glycogen storage disease). Can't de - plate G6P (glycogenolysis & gluconeogenesis). Severe fasting hypoglycemia - inc. glycogen in liver - inc. blood lactate (gluconeogenesis impaired) - hepatomegaly.


3. Converts adenosine to inosine in purine salvage pathway. Excess ATP - dATP in nucleotide pool = imbalance (feedback inhibition of ribonucleotide reductase - preventing DNA synthesis) - so decreased lymphocyte count (major cause of SCID - severe combi






4. Glycogen debranching enzyme (alpha -1 -6 glucosidase) deficiency (type III glycogen storage disease). Like type I (Von Gierke's; glucose -6- phosphatase deficiency) but milder (gluconeogensis intact; normal blood lactate levels)


5. Bleeds (gamma - carboxylation of glutamic acid residues on factors II - VII - IX - X - protein C - S). Neonatal hemorrhage (inc PT - aPTT - normal bleeding time - sterile intestine in newborn - can't synthesize vitK - synthesized by intestinal flora






6. Aut - dom; mutation of NF2 gene (chr 22: 'type 2 = 22'). Bilateral acoustic neuromas - juvenile cataracts.






7. Trisomy 21; MR - flat facies - epicanthal folds - simian crease - gap btwn 1-2nd toes - duodenal atresia - congenital heart dz (esp septum - primum - type ASD) - a/w inc risk All - Alz dz (>35 y/o). #1 cause congenital MR; #1 chr disorder (1:700). 95






8. X- linked frame - shift mutation: deletion of dystrophin (DMD anchors mm fibers - esp. skeletal / cardiac. Longest gene: lots of spontaneous mutations). Accel. mm breakdown (weakness in pelvic girdle -> superiorly). Pseudohypertrophy of calf mm (fibr


9. Aut - rec (CFTR gene - chr 7; CFTR channel secretes Cl - in lungs / GI - resorbes Cl - from sweat). Thick mucus - plugs lungs - pancreas - liver. Recurrent pulm infections (Pseudomonas - S aureus) - chronic bronchitis - bronchiectasis - pancreatic in






10. B1 (thiamine) deficiency. Polyneuritis - symmetrical muscle wasting






11. High output cardiac failure (dilated CM) - edema






12. Aut - dom; deletion of VHL gene (tumor suppressor) on chr 3 (3 words for chr 3). Results in constitutive expression of HIF (transcription factor) - activation of angiogenic growth factors. Hemangioblastomas of retina / cerebellum / medulla - 50% get






13. A 22q11 deletion syndrome. Palate - facial - cardiac defects. Microdeletion at chr 22q11. Due to aberrant development of 3rd / 4th branchial pouches.






14. Mutation in mismatch repair genes (mismatched nucleotides in unmethylated / newly synthesized string recognized + removed)






15. Aut - rec - 3 forms. All interfere with conversion of methionine to cysteine - cysteine becomes essential; homocysteine accumulates. Causes: 1) cystathionine synthase deficiency (Tx: dec Met - inc. Cys intake. Inc B12 / folate in diet to drive conver






16. Aut - dom; defective / absent LDL receptor. Elevated LDL. Heterozygotes (1:500) have cholesterol = 300 mg/dL. Homozygotes (rare) chol > 700 mg /dL - severe atherosclerotic dz early in life - tendon xanthomas (classically Achilles); may have MI < 20 y






17. Type IV familial dyslipidemia. Hepatic overproduction of VLDL; VLDL increased; blood TGs elevated






18. X- linked mutated dystrophin. Less severe than Duchenne's. Onset: adolescence - early adulthood.


19. Aut - rec deficiency in apoB-100 (binds LDL receptor; mediates VLDL secretion) and apoB-48 (mediates chylomicron secretion) - so can't synthesize lipoproteins. Sx appear in 1st months of life: FTT - steatorrhea - acanthocytosis (= RBC with spikes - '






20. Microtubule polymerization defect (no lysosomal tracking). Decreased phagocytosis. Recurrent pyogenic infections - partial albinism - peripheral neuropathy.






21. A 22q11 deletion syndrome. Thymic - parathyroid - cardiac defects. Microdeletion at chr 22q11. Due to aberrant development of 3rd / 4th branchial pouches.






22. X- linked recessive. G6PD: G6P + NADP+ -> 6PG + NADPH; NADPH needed to reduce GSSG to 2GSH (glutathione reductase) for H2O2 to 2H2O conversion. Only pathway for making reduced GSH in RBC - so can't detoxify free radicals / peroxides (fava beans - sul






23. Type I familial dyslipidemia. Lipoprotein lipase deficiency or altered apolipoprotein C- II (LPL cofactor) = can't degrade TG circulating in chylomicrons - VLDLs. Increased chylomicrons - elevated cholesterol / TGs in blood






24. Lysosomal storage disease (a sphingolipidosis). Aut - rec deficiency of sphingomyelinase; sphingomyelin accumulates. Progressive neurodegeneration - hepatosplenomegaly - cherry- red spot on macula - foam cells.






25. Rare; from abx or excessive raw egg ingestion (avidin in whites binds biotin). Dermatitis - alopecia - enteritis. Biotin used in carboxylation enzymes.






26. Chr 15 - normally active maternal (AngelMan = maternal) allele deleted. MR - seizures ataxia - inappropriate laughter ('happy puppet'). Other parent's allele inactivated / imprinted by methylation; can also be from uniparental disomy (2 copies of chr


27. Energy malnutrition. Tissue / muscle wasting - loss of subQ fat - variable edema.






28. Variable inheritance (locus heterogeneity); vs ocular albinism (x- linked recessive). Congenital deficiency of either 1) tyrosinase (can't make melanin from tyrosine; aut - rec); 2) defective tyrosine transporters (dec. tyrosine = dec. melanin); can






29. Hypercalcemia - hypercalciuria - loss of appetite - stupor. Seen in sarcoidosis (inc. activation of vitamin D by epithelioid macrophages).






30. Aut - dom; mutation of huntingtin (chr 4 - 'hunting 4 food') - CAG repeats. Depression - progressive dementia - choreiform movements - caudate atrophy; manifests 20-50 y/o. Dec GABA - ACh in brain.


31. Cheilosis - corneal vascularization (the 2 C's)






32. Aut - dom; I/II/III - familial tumors of endocrine glands (pancreas - parathyroid - pituitary - thyroid - adrenal medulla). II / III a/w ret gene






33. Dec alpha - ketoacid dehydrogenase activity = blocked degradation of branched amino acid (Ile - Leu - Val = I Love Vermont; maple trees w/ branches). Increased alpha - ketoacids in blood (esp Leu). Severe CNS defects - MR - death. Urine smells like m






34. Aut - dom - Fibrillin defect (scaffolding for elastin formation - stretchy protein for lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava). Connective tissue disorder: skeleton - heart - eyes affected. Tall - long extremities


35. Adult polycystic kidney disease. Aut - dom - 90% from mutation in APKD1 - chr 16 (16 letters in 'polycystic kidney'). Always bilateral - big kidneys (lots of big cysts). Flank pain - hematuria - HTN - progressive renal failure. a/w polycystic liver d






36. Night blindness - dry skin






37. Lysosomal alpha -1 -4- glucosidase (acid maltase) deficiency (type II glycogen storage disease. Lysosomal degradation of glycogen impaired (1 -4 = linkages - not branches). Cardiomegaly - systemic findings (liver - muscle) leading to early death. Pom


38. Peroxisomal disease; can't metabolize very long chain FA (VLCFAs) or branched - chain FAs (e.g. phytanic acid - via alpha - oxidation). Can't form myelin in CNS. Hypotonia - seizures - hepatomegaly - MR - early death.






39. Acquired (e.g. liver dz) or hereditary (urea cycle enzyme deficiencies). inc. NH4 depletes alpha - keotglutarate - inhibiting TCA cycle. Ammonia intox - tremor - slurred speech - somnolence - vomiting - cerebral edema - blurred vision. Tx with benzoa






40. Aut - rec deficiency of homogentisic acid oxidase (degradative pathway of tyrosine) - benign disease. Dark connective tissue - pigmented sclera - urine turnes black on standing - may have debilitating arthralgias.






41. X- linked rec; most common urea cycle disorder (others aut - rec). Can't eliminate ammonia; often dx'd perinatally but can be later. Dx: orotic acid in blood / urine (excess carbamoyl phosphate converted to orotic acid) - dec. BUN - hyperammonemia sx






42. Lysosomal storage disease (a sphingolipidosis). X- linked recessive (all other sphingolipidoses AR); deficiency of alpha - galactosidase A ceramide trihexoside accumulates. Peripheral neuropathy (hands / feet) - angiokeratomas - CV / renal disease


43. Inclusion cell disease. Can't add mannose -6- P to lysosome proteins. Enzymes secreted outside of cell instead of targeted to lysosome. Lysosomal storage disorder. Coarse facial features - clouded corneas - restricted joint movement - high plasma lev






44. Aut - rec galactokinase deficiency. Galactitol can accumulate if galactose present in diet; relatively mild. Galactose in blood / urine - infantile cataracts (may not track objects - develop social smile.






45. X- linked dominant disorder (M/F offspring of affected mom can be affected; all female offspring of affected father diseased). Inc. phosphate wasting at proximal tubule; rickets - like presentation






46. Severe vitamin B3 (niacin) deficiency (less severe = glossitis). Diarrhea - dementia - dermatitis. Can be caused by Hartnup disease (dec. tryptophan absorption) - malignant carcinoid syndrome (inc tryptophan metabolism) (B3 made from tryptophan) and






47. Mitochondrial inheritance (only transmitted via mom); degeneration of retinal ganglion cells / axons; acute loss of central vision


48. Lysosomal storage disease (a sphingolipidosis) - Aut - rec deficiency of beta - glucocerebrosidase; glucocerebroside accumulates. Hepatosplenomegaly - aseptic necrosis of femur - bone crises - Gaucher's cells (macrophages that look like crumpled tiss


49. Inhibits lipoic acid (required for pyruvate dehydrogenase complex - pyruvate to acetyl - coA). Vomiting - rice water stools - garlic breath.






50. Peroxisomal disease; no alpha - oxidation of branched - chain FA like phytanic acid. Neuro sx; Tx = avoid chlorophyll