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






2. 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


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






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


5. Night blindness - dry skin






6. 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.






7. 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






8. 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






9. 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


10. 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






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






12. Aut - rec deficiency of aldolase B; fructose -1- P accumulates; dec. in phosphate = inhibition of glycogenolysis / gluconeogenesis. Hypoglycemia - jaundice - cirrhosis - vomiting. Tx: limit fructose - sucrose (gluc + fruc) intake.






13. 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'






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






15. 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






16. 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


17. 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


18. 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






19. 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






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






21. Brittle bone disease; genetic bone disorder. Variety of gene defects. Type II fatal in utero - neonatal. Most common form: AD with abnormal type I collagen (bone): multiple fractures w/ minimal trauma (e.g. during birth) - blue sclerae (translucent c






22. 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






23. 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






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






25. 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


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






27. 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.






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






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






31. 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






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






33. Protein malnutrition. Skin lesions - edema - liver malfunction (fatty change). Small child - swollen belly.






34. 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 - '






35. 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






36. 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






37. 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.


38. 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






39. Immobile cilia (dynein arm defect). Infertility (M/F; sperm immotile) - bronchiectasis - recurrent sinusitis (not pushing out bacteria / particles). A/W situs inversus


40. 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






41. 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






42. 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






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






44. 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).






45. 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






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






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






48. 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






49. Skeletal muscle glycogen phosphorylase deficiency (normally breaks down glycogen to 4- glucose residue branched 'limit dextrans'). Type V glycogen storage disease. Incr. glycogen in mm - but can't break down (mm cramps - myoglobinuria with strenuous


50. 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