Biochemistry - Diseases - Full Biochem listttttt Flashcards Preview

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Flashcards in Biochemistry - Diseases - Full Biochem listttttt Deck (82)
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1

Orotic Aciduria

-Inability to convert orotic acid to UMP bc of defect in UMP synthase

-AR

-Findings: Increased orotic acid in urine, megaloblastic anemia, FTT. No hyperammonemia (excess ammonia in the blood)

-Treatment: Oral uridine administration

2

Adenosine Deaminase (ADA) Deficiency

-AR** --> SCID

-can't break down Adenine/AMP/ATP (can't convert Adenosine --> Inosine**)

-excess ATP and dATP inhibit ribonucleotide reductase by negative feedback (prevents DNA synthesis)

-Decreased lymphocyte count (accumulation of adenosine is toxic to lymphocytes)

3

Lesch-Nyhan Syndrome

-X-linked Recessive

-Absence of HGPRT --> defective purine salvage

-Findings: retardation, self-mutilation, aggression, hyperuricemia, gout, choreoarthetosis (involuntary movements)

4

I-cell (Inclusion Cell) disease

-failure of addition of Mannose6P to lysosome proteins --> enzymes secreted out of cell

-Findings: Coarse facial features, clouded corneas, restricted joint movement, high plasma level of lysosomal enzymes

-Often fatal in childhood

5

Chediak-Higashi Syndrome

-Mutation in lysosomal trafficking regulator gene (LYST) - the product is required for the MT dependent sorting of endosomal proteins into late multivesicular endosomes

-Findings: pyogenic infections, partial albinism (trbls w melanosome trafficking), and peripheral neuropathy

6

Kartagener's syndrome (primary ciliary dyskinesia)

-Dynein arm defect --> immotile cilia

-Findings: male infertility, decreased female fertility, bronchiectasis, recurrent sinusitus

-assoc with situs inversus

7

Osteogenesis Imperfecta

-AD, abnormal type 1 collagen

-Findings: Multiple fractures, blue sclerae (translucency of the CT over the choroidal veins), Hearing loss (abnl middle ear bones), Dental imperfections (lack of dentin)

8

Ehlers-Danlos Syndrome

-6 types, inheritance and severity vary

-AD or AR  --> Hyperextensible skin, tendency to bleed (easy bruising), hypermobile joints

-Assoc with joint dislocation, BERRY ANEURYSMS, organ rupture

common mutations: can't cross link collagen (decr lysyl-hydroxylysyl bonds), missing pro-collagen peptidase (can't cleave SS-rich temrinal ends to make collagen insoluble)

9

Alport Syndrome

-Varying gene defects --> abnl type 4 collagen (BM, ears, eyes)

-Most common: X-linked recessive

-Progressive hereditary nephritis, deafness

-May be assoc w ocular disturbance

10

Prader-Willi Syndrome

-Defect in Paternal allele on chr 15 (maternal already imprinted/silenced)

-Mental retardation, hyperphagia (over eating), obesity, hypogonadism, hypotonia

11

AngelMan's syndrome

-Defect in Maternal allele (chr 15), paternal allele already imprinted

-Mental retardation, seizures, ataxia, inappropriate laughter (Angel!)

12

Achondroplasia

-Cell-signaling defect in Fibroblast Growth Factor (FGF) receptor 3  (activating mutation, inhibits chondrocyte proliferation)--> Dwarfism, short limbs, relatively larger head (trunk size is normal)

-Assoc w advanced paternal age

-AD

-homozygous? die in utero/shortly after birth

13

AD Polycystic Kidney Disease (ADPKD)

-AD

-massive enlargement of BL kidneys, multiple large cysts

-Findings: flank pain, hematuria, HTN, progressive renal failure

-85%: mutation in PKD1 (chr 16)

-Assoc w polycystic LIVER disease, BERRY ANEURYSMS, MITRAL VALVE PROLAPSE*

-Inftanile form: AR

(kidney cysts look like BERRYs!)

14

Familial adenomatous polyposis

-AD

-Mutations on chr 5 (five letters in 'polyp')

-Colon becomes covered w adenomatous polyps after puberty --> colon ca unless colon is resected

(F --> Five, A --> APC, P --> Polpyposis)

15

Familial hypercholesterolemia (hyperlipidemia type IIA)

-AD

-Defective or absent LDL receptor --> elevated LDL

-Heterozygotes (1:500) have cholesterol ~300 -Homozygotes (very rare) cholsterol >700, severe atherosclerotic disease early in life, and achilles tendon xanthomas, MI may develop <20 yrs

16

Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu Syndrome)

-AD

-Disorder of blood vessels

-Findings: telangiectasia, recurrent nose-bleeds/epistaxis, skin discolorations*, AV malformations*

(can be in skin, mucous membranes, GI, respiratory tract, urinary tract (epistaxis, GI bleeds, hematuria)

17

Hereditary Spherocytosis

-AD

-spectrin or ankyrin defect --> spheroid erythrocytes

-hemolytic anemia, increase MCHC*** diagnostic (relatively incr hgb concentration due to smaller rbcs)

-Rs: Splenectomy

18

Huntington's disease

-AD

-Findings: depression, progressive dementia, choreiform mvmts, CAUDATE ATROPHY, decreased levels of GABA and ACh in the brain

-Sxs manifest between 20-50

-Gene located on chr 4

-Trinucleotide repeat disorder (CAG)

CAG4

19

Marfan's syndrome

-AD

-Fibrillin-1 gene mutation --> CT disorder affecting skeleton, heart, and eyes

-Findings: tall w long extremities, pectus excavatum, hypermobile joints, long, tapering fingers and toes (arachnodactyly), scolosis and/or Kyphoscoliosis

--> cystic medial necrosis of aorta --> aortic incompetence and dissecting aortic aneurysms, Berry aneurysm*

--> Floppy mitral valve/MVP**

-Subluxation of lenses

-death by conduction defects (more common than aortic dissection)

20

Multiple endocrine neoplasias (MEN)

-AD

-Type 1: Pituitary, Parathyroid, Pancreas

-Type 2: Medullary thryoid ca., Parathyroid, Pheo's

-Type 3: Marfinoid habitus, medullary thyroid cancer, oral nodules, Pheo's

-MEN 2A and 2B ~ ret gene

21

Neurofibromatosis type 1 (von Recklinghausen's disease)

-AD

-Findings: cafe-au-lait spots (inguinal/axial freckles), neurofibromas, Lisch nodules (pigmented iris hamartomas)

-Also skeletal disorders (e.g. scoliosis)

-optic gliomas (assoc w meningiomas as well)

-on long arm of chr 17

-100% penetrant, variable expression*

22

Neurofibromatosis type 2

-AD

-Bilateral acoustic schwannomas, juvenile cataracts

-NF2 gene on chr 22

23

Tuberous sclerosis

-AD

-HAMARTOMAS: in CNS and skin

-Adenoma sebaceum (cutaneous angiofibromas)

-Ash leaf spots 

-cardiac Rhabdomyoma**, mitral regurg

-Mental retardation, seizures

-renal Angiomyolipoma**

-Incomplete penetrance, variable presentation

24

von Hippel-Lindau disease

-AD -Findings: HEMANGIOBLASTOMAS of retina/cerebellum/medulla, PHEOS

-Majority develop multiple bilateral RENAL cell carcinomas and other tumors

-cavernous hemangiomas in skin, mucosa, organs.

-Assoc w deletion of VHL gene (tumor suppressor) on chr 3 (3p) - nl inhibits HIF (hypoxia inducible factor)--> Results in constituitive expression of HIF (TF) and activation of angiogenic growth factors

VHL = VMA (pheo), Hemangioblastomas, renaL. 3 letters = chr3

25

Cystic Fibrosis

-AR

-defect in CFTR (normally actively secretes Cl- in lungs and GI tract, actively reabsorbs Cl- from sweat AND INHIBITS NA+ REABSORPTION)

-abnormally thick mucus (plugs lungs, pancreas, liver)

-pancreatic insufficiency (malabsorption and steatorrhea - excess fat in feces)

-nasal polyps, meconium ileus in newborns

-mutation causes abnl protein folding --> degradation of channel BEFORE reaching cell surface

-Infertility of males due to bilateral ABSENCE of vas deferences

-Fat-soluble vitamin deficiencies (A,D,E,K)

-Rx: N-acetylcysteine to loosen mucus plugs (cleaves S-S bonds within mucous glycoproteins)

26

Duchene's

-X-linked frameshift mutation -->deletion of dystrophin gene --> accelerated muscle breakdown

-Starts pelvic girdle mm --> progresses superiorly

-Pseudohypertrophy of calf muscles (fibrofatty replacement of mm), cardiac myopathy

-Gower's maneuver +

-Onset before age 5

-Diagnose: Increased CPK (muscle breakdown), muscle biopsy

27

Becker's

-X-linked mutated dystrophin gene

-Less severe than Duchene's  (so onset later)

-Onset in adolescence or early childhood

28

Fragile X syndrome

-X-linked defect

-Trinucleotide repeat: CGG

-affected: methylation and inexpression of FMR1 gene

-2nd most common cause of genetic mental retardation

-Findings: macroorchidism, long face w large jaw, large everted ears, AUTISM, MITRAL VALVE PROLAPSE**

"Xtra large testes, ears, jaw, Mitral valve, Xtra CGG, and Xtra ANAL (kinda like autism?)"

29

Down Syndrome

-Trisomy 21

-Findings: Mental retardation, flat facies, prominent epicanthal folds, simian crease (hand-line), gap btwn toes 1-2, duodenal atresia, ASD

-Incr risk of ALL, Alzheimers (>35 yrs)

-95% due to nondisjxn (advanced M age)

-4% due to Robertsonian translocation

-1% due to Down mosaicism

-Most common cause of genetic mental retardation

-Screening: incr B-Hcg, inhibinA, nuchal translucency. Decr AFP and estriol

30

Edwards' Syndrome

-Trisomy 18

-Findings: severe mental retardation, rocker-bottom feet, micrognathia (small jaw), low-set ears, CLENCHED HANDS, prominent occiput, CHD

-death w/in 1 yr

-Screening: Decr AFP, B-hCG, estriol. NORMAL inhibin A