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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. 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


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. 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






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


5. 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


6. 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






7. 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






8. 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






9. 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






10. 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.






11. 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






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






13. 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'






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






15. Lysosomal storage disease (a sphingolipidosis). Aut - rec deficiency of galactocerebosidase; galactocerebroside accumulates. Peripheral neuropathy - developmental delay - optic atrophy - globoid cells (multinucleated).


16. 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






17. 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


18. 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.


19. Aut - rec deficiency of phenylalanine hydroxylase / THB (cofactor) - so can't convert phenylalanine to tyrosine. Results: accumulate phenylalanine (excess phenylketones in urine); tyrosine becomes essential AA. Dx: MR - growth retardation - seizures






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






21. Aut - rec - defect in renal tubular AA transporter (cysteine - ornithine - lysine - arginine in renal PCT). inc. cystine (2 cysteines w/ disulfide bond) in urine --> cystine kidney stones (cystine staghorn calculi). Common (1:7000); Tx with acetazola






22. Rickets in children (bending bones); osteomalacia in adults (soft bones). Also hypocalcemic tetany.






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


24. 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






25. Aut - dom. Facial lesions (adenoma sebaceum) - hypopigmented 'ash - leaf spots' on skin - cortical / retinal hamartomas - seizures - MR - renal cysts - renal angiomyolipomas - cardiac rhabdomyomas. Inc. incidence astrocytomas. Incomplete penetrance w






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






27. Type IIa familial dyslipidemia. Aut - dom absence / decrease in LDL receptors. LDLs increased - blood cholesterol elevated.






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. 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


30. Trisomy 13 (P = puberty age) - 1:15 -000. Severe MR - rockerbottom feet - congenital heart disease. Vs. Edwards': cleft lip / Palate - holoProsencephaly - Polydactyly (P's) - micropthalmia - microcephaly. Death w/in 1 yr


31. Scurvy - swollen gums - bruising - anemia - poor wound healing. In fruits / vegetables. Facilitates Fe absorption: keeps Fe2+ reduced state - more absorbable. Also involved in hydroxylation of proline - lysine in collagen synthesis; antioxident; need






32. 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






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






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






35. 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


36. Variable presentation - incl CATCH-22: Cleft palate - Abnormal facies - Thymic aplasia / T- cell deficiency - Cardiac defects - Hypocalcemia (2ary to parathyroid aplasia) - from microdeletion at chr 22q11. Due to aberrant development of 3rd / 4th bra






37. Aut - dom; disorder of blood vessels. Telangiectasia - recurrent epistaxis - skin discolorations - AVMs. Incr. in Utah Mormons






38. 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






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






40. 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






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






42. 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






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






44. 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.






45. 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






46. X- linked recessive - absence of HGPRT (hypoxanthine to IMP - guanine to GMP in purine salvage pathway). Can't salvage purines - so increased elimination = incr uric acid production. Retardation - self - mutilation - aggression - hyperuricemia - gout






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






48. 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


49. 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


50. Microdeletion of short arm of chr 5: 46 -XX or XY - 5p -. Microcephaly - moderate/severe MR - high pitched crying/mewing (cry of the cat) - epicanthal folds - cardiac abnormalities