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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. 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






2. 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






3. Aut - dom cell - signaling defect in fibroblast growth factor receptor 3 (FGFr3). Dwarfism: short limbs but head/trunk normal. A/W advanced paternal age






4. 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






5. 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.






6. Lysosomal storage disease (a mucopolysaccharidosis). X- linked rec deficiency of iduronate sulfatase; heparan sulfate - dermatan sulfate accumulate. Mild Hurler's phenotype (developmental delay - gargoylism (thickened gingiva + upturned nose) - airwa


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






8. Macrocytic - megaloblastic anemia w/o neuro sx. #1 vitamin deficiency in USA; see in alcoholism / pregnancy (neural tube defects; supplement in early pregnancy) - also drugs (phenytoin - sulfas - MTX). From FOLiage (leafy greens) with small reserve p






9. Aut - rec; can't convert orotic acid to UMP in de novo pyrimidine synthesis pathway (defect in orotic acid PRT or orotidine 5''- P- decarboxylase. Incr. orotic acid in urine - megaloblastic anemia (that doesn't get better with B12 / folate supplement






10. Lysosomal storage disease (a mucopolysaccharidosis). Aut - rec deficiency of alpha - L- iduronidase; heparan sulfate - dermatan sulfate accumulate. Developmental delay - gargoylism (thickened gingiva + upturned nose) - airway obstruction - corneal cl


11. Aut - dom; mutation on long arm of chr 17 (17 letters in 'von recklinghausen') cafe - au - lait spots - neuronal tumors - Lisch nodules (pigmented iris hamartomas). Skeletal disorders (eg scoliosis) - optic pathway gliomas - pheochromocytoma - increa


12. 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






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






14. (Pyruvate + NAD+ + CoA --> acetylCoA + CO2 + NADH; 3 enzymes - requires B1 -2 -3 - CoA - lipoic acid). Pyruvate - alanine accumulate --> lactic acidosis (pyruvate to lactate). Congenital or acquired (e.g. alcoholics - B1 deficiency - lactic acidosis!






15. Lysosomal storage disease (a sphingolipidosis). Aut - rec deficiency of arylsulfatase A - cerbroside sulfate accumulates. Central / peripheral demyelination - ataxia - dementia.






16. 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


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


18. Age dep or hereditary lactose intolerance (blacks / Asians); lose brush - border enzyme. Bloating - cramps - osmotic diarrhea. Avoid dairy / use lactase pills.






19. 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.






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






21. 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






22. Faulty collagen synthesis: hyperextensible skin - tendency to bleed (easy bruising) - hypermobile joints. Mostly type III collagen. 6 types - inheritance / severity vary (AD/AR). A/w joint dislocation - berry aneurysms - organ rupture






23. Hemolytic anemia (inc fragility of erythrocytes - vit E is antioxidant - protects erythrocytes / membranes from free - radical damage). Muscle weakness - neurodysfunction tooo.






24. Cobalamin = B12. macrocytic - megaloblastic anemia. Neuro sx: paresthesias - subacute combined degeneration from abnormal myelin. Prolonged deficiency = irreversible nervous system damage. Found in animal products; synthesized only by microorganisms.






25. 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






26. 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


27. 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






28. Chr 15 - normally active parental (Prader = parental) allele deleted. MR - hyperphagia - obesity - hypogonadism - hypotonia. Other parent's allele inactivated / imprinted by methylation; can also be from uniparental disomy (2 copies of chr from 1 par






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






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






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






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






33. Aut - dom - defect in spectrin or ankyrin. Hemolytic anemia - increased MCHC (mean corpuscular hemoglobin concentration). Splenectomy is curative






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






35. Defects in type IV collagen synthesis; most common form X- linked recessive. Hereditary nephritis - deafness +/- ocular disturbances (type IV collagen important in BM of kidney - ears - eyes)


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






37. Lysosomal storage disease (a sphingolipidosis). Aut - rec deficiency of hexosaminidase A; GM2 ganglioside accumulates. Progressive neurodegeneration - developmental delay - cherry- red spot on macula - lysosomes with 'onion skin'






38. Pyridoxine = B6. Convulsions - hyperirritability - peripheral neuropathy. Deficiency inducible by INH - oral contraceptives. Converted to pyridoxal phosphate: used in transamination (ALT - AST - etc) - decarboxylation - glycogen phosphorylase - heme






39. 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


40. 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)


41. Aut - rec absence of galactose -1- phosphate uridyltransferase; toxic substances accumulate (e.g. galactitol in lens of eye). FTT - jaundice - hepatomegaly - infantile cataracts - MR. Tx: no galactose / lactose (glucose + galactose).






42. 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






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






44. Aut - dom; mutation in APC gene (chr 5 - 'polyp' has 5 letters). Colon covered with adenomatous polyps after puberty. Progresses to colon cancer unless resected






45. Delayed wound healing - hypogonadism - dec. adult hair (axillary / facial / pubic); ?predispose to alcoholic cirrhosis?






46. 'Bear liver'guy - arthralgias - fatigue - headaches - skin changes - sore throat - alopecia. Also teratogenic (cleft palate - cardiac abnormalities)






47. Aut - rec fructokinase deficiency. Can't P- late fructose - so can't enter cells. Benign - asymptomatic - just fructose in blood - urine.






48. Mutation in nucleotide excision repair proteins (endonucleases that release oligonucleotides containing damaged bases; DNApol + ligase fill in). Can't repair thymidine dimers (UV light). Dry skin with melanoma + other cancers ('children of the night'






49. X- linked trinucleotide repeat disorder (CGG); affects methylation / expression of FMR1 gene - a/w chromosomal breakage. #2 cause of genetic MR (Down's is #1). Macro - orchidism - long face + large jaw - large everted ears - autism.






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