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86 Cards in this Set

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What are the FAT soluble vitamins?
ADEK

**Absorption depends on gut (ileum) and pancreas
=malabsorption syndromes (steatorrhea) such as CF and SPRUE or MINERAL OIL INTAKE can cause fat-soluble vitamin deficiencies

**Toxicity MORE COMMON than for water-soluble vitamins--i.e. these accumulate in fat!
What are the WATER soluble vitamins?
B1 (=thiamine: TPP)
B2 (=riboflavin: FAD, FMN)
B3 (=niacin: NAD+)
B5 (=panthothenate: CoA)
B6 (=pyridoxine: PP)
B12 (=cobalamin)
C (=ascorbic acid)
Biotin
Folate
About water soluble:
**all wash out easily from the body EXCEPT B12 (=stored in the liver)

**B-complex deficiencies often result in dermatitis, glossitis, and diarrhea.
Vitamin A = Function
(retinol)

**Found in leafy veggies
=constitutent of visual pigments (retinal)

**Retin-A used topically to treat wrinkles and acne
Deficiency
night blindness, dry skin
Excess
=arthralgias
=fatigue
=HA
=skin changes
=alopecia
=sore throat
Vitamin B1 Function
(thiamine)

**A component of THIAMINE PYROPHOSPHATE = a cofactor for oxidative decarboxylation of alpha ketoacids (=pyruvate, alpha-ketoglutarate)

**Also a cofactor for TRANSKETOLASE in the HMP shunt
Deficiency
**Beriberi

**Wernicke-Korsakoff Syndrome

=seen in alcholism and malnutrition
Dry Beriberi
=polyneuritis, muscle wasting
Wet Beriberi
=high output cardiac failure (dilated cardiomyopathy)

=edema
Vitamin B2
(riboflavin)

=cofactor in oxidation and reduction (i.e. FADH2 --> FAD and FMN are derived from riboFlavin!)
Deficiency
=angular stomatitis

=cheilosis

=corneal vascularization
Vitamin B3
(niacin)

**Constitutent of NAD, NADP
=used in redox reactions

**Derived from TRYPTOPHAN using vitamin B6
Deficiency
Pellagra

NOW, pellagra can be caued by 3 mechanisms:

1) Hartnup disease
=dec. tryptophan absorption
2) Malignant carcinoid syndrome
=inc. tryptophan metabolism
3) INH
=dec. vitamin B6
Sympotoms of Pellagra:
**The 3 D's:

1) Diarrhea
2) Dermatitis
3) Dementia

+ beefy glossitis
Vitamin B5
(pantothenate)

**Constituent of Coa (=cofactor for acyl transfers)

**Component of fatty acid synthase
Deficiency:
=dermatitis
=enteritis
=alopecia
=adrenal insufficiency
B6
(pyridoxine)

**Converted to pyridoxal phosphate, a COFACTOR used in:
1) Transamination (ALT, AST)
2) Decarboxylation
3) Heme Synthesis
Deficiency
=convulsions
=hyperirritability
=peripheral neuropathy

**Deficiency inducible by:
=INH
=oral contraceptives
Vitamin B12
(cobalamin)

**Cofactor for homocysteine methylation (transfers CH3 groups as methylcobalmin) AND methylmalonyl-CoA handling
Where Found?
**Found ONLY in animal products.

=stored primarily in the liver--> large reserve pool (years)
What usually causes deficiency?
1) Malabsorption
=sprue
=enteritis
=diphyllobothrium lactum

2) Lack of intrinsic factor (=pernicious anemia)

3) Absence of a terminal ileum
=Crohn's disease

**Use Schilling's test to detect deficiency
Deficiency?
=macrocytic, megaloblastic anemia

=neurological symptoms

=glossitis
What else is seen in B12 Deficiency?
**Abnormal myelin
=possibly due to DECREASED methionine or INCREASED methylmalonic acid (=from metabolism of accumulated methylmalonyl-CoA)
Folic Acid Function
**Coenzyme (tetrahydrofolate) for 1-carbon transfer

**Involved in methylation reactions

**Impt. for the synthesis of nitrogenous bases in RNA and DNA
Found?
**Green leaves
=NOT stored long!

**PABA is the folic acid precursor in bacteria
=i.e. SULFA drugs and DAPSONE (antimicrobials) are PABA analogs

**Take folic acid in early preggers to prevent NT defects
Deficiency
**MOST COMMON deficiency in US

=macrocytic, megaloblastic anemia
=NO neurological symptoms
Biotin
**Cofactor for carboxylations:

1) Pyruvate --> oxaloacectate
2) AcetylCoA --> malonyl-CoA
3) Proprionyl-CoA --> methylmalonyl-CoA
Deficiency?
**Caused by antibiotic use OR ingestion of raw eggs

=dermatitis
=enteritis
Vitamin C (ascorbic acid)
**Necessary for hydroxylation of proline and lysine in collagen synthesis
=vitamin C CROSSLINKS collagen

**Facilitates iron absorption by keeping iron in Fe2+ reduced state

**Necessary as a cofactor for dopamine --> NE
Deficiency
**SCURVY:
=swollen gums
=bruising
=anemia
=poor wound healing
Vitamin D FORMS
D2 = ergocalciferol; consumed in milk

D3 = cholecalciferol; formed in sun-exposed skin

25-OH D3 = storage form

1,25 (OH2) D3 = active form
Function:
=increased intestinal absorption of calcium and phosphate
Deficiency:
1) Rickets in kiddos (=bending bones)

2) Osteomalacia in adults (=soft bones)

3) Hypocalcemic tetany
Excess:
**Hypercalcemia
=loss of appetitie
=stupor

**Seen in SARCOIDOSIS
=epitheliod macrohpages convert vitamin D to its active form
Vitamin E
**ANTIOXIDANT
=protects erythrocytes from hemolysis

Vitamin E = Erythrocytes
Deficiency:
**Increased fragility of erythrocytes, neurodysfunction
Vitamin K
**Catylzes the gamma-carboxylation of glutamic acid residues on the vitamin K-dependent factors: 2, 7, 9, 10, protein C and S

recall: WARFARIN is a vitamin K antagonist!

**Synthesized by intestinal floria
=THERFORE, deficiency can occur after broad-spectrum antibiotics
Deficiency
**Neonatal Hemorrhage
=increased PT and aPTT but NORMAL bleeding time
=i.e. neonates have sterile intestines --> can't synthesize vitamin K
Zinc Deficiency
**Delayed wound healing

**Hypogonadism
=decreased adult hair (axillary, facial, pubic)

**MAY predispose to alcoholic cirrhosis
Ethanol Metabolism
**NAD+ is the limiting reagent

**Alcohol dehydrogenase operates via ZERO-ORDER kinetics
What can inhibit acectaldehyde dehydrogenase?
=Disulfiram (Antabuse)

THUS, acetaldehyde accumulates --> hangover symptoms
Ethanol Hypoglycemia
**Ethanol metabolism INCRASES NADH/NAD+ ratio in the liver
=causes diversion of pyruvate --> lactate and OAA --> malate
=this INHIBITS gluconeogenesis and leads to hypoglycemia

**This same altered HADH/NAD+ ratio is responsible for the FATTY CHANGE (hepatocellular steatosis) seen in chronicc alcoholics!
=shunting AWAY from glycolysis and toward fatty acid synthesis!
Kwashiokor
**PROTEIN malnutrition

=skin lesions
=edema
=liver malfunction (fatty change)

**Clinical picture is a small child with a SWOLLEN belly

Kwashiorkor results from a protein-deficient MEAL = malabsorption, edema, anemia, liver (fatty)
Marasmus
**Energy (total calorie) malnutrition resulting in:

=tissue and muscle wasting
=loss of subcutaneous fat
=variable edema
Autosomal Dominant Diseases
1) APKD
2) Familial Hypercholestrolemia
3) Marfan's Syndrome
4) Neurofibromatosis
5) Tuberous Sclerosis
6) Von Hippel-Lindau
7) Huntington's
8) Familial Adenomatous Polyposis
9) Hereditary Spherocytosis
10) Achondroplasia
Adult Polycystic Kidney Disease
**Always BILATERAL
=massive enlargement of kidneys because of large cysts

**Due to mutation in APKD1 (=chromosome 16)

**Note: Juvenille form is recessive
Presentation:
=pain
=hematuria
=HTN
=progressive renal failure

**Associated with: polycystic liver disease, berry aneurysms, mitral valve prolapse, sigmoid diverticulosis
Familial hypercholestrolemia
(Hyperlipidemia Type IIa)

**Elevated LDL because of DEFECTIVE or ABSENT LDL receptor

=Heterozygotes have cholesterol ~ 300
=Homozygotes have cholesterol ~ 700+
Presentation:
**Severe atherosclerotic disease in early life

**Tendon xanthomas (=Achille's tendon)

**MI may develop before age 20
Marfan's Syndrome
**Fibrillin gene mutation --> CT disorders
Presentation:
1) Skeletal abnormalities
=tall with long extremities (arachnodactyly)
=pectus excavatum
=hyperextensive joints
=long, tapering fingers and toes

2) CV
=cystic medial necrosis of the aorta --> aortic incompetance and dissecting aortic aneurysms
=mitral valve prolapse

3) Subluxation of lenses
Neurofibromatosis Type I

=von Recklinhausen's Disease
**Defect on chromosome 17
=cafe-au-lait spots
=neural tumors
=lisch nodules (pigmented iris hamartomas)

Also: scoliosis, optic pathway gliomas, pheochromycytoma
Neurofibromatosis Type II
**Bilateral acoustic neuroma

**Juvenille cataracts

NF2 gene on chromosome 22
Tuberous Sclerosis
**Incomplete penetrance
=variable presentation

=facial lesions, seizures, mental retardation
=hypopigmented "ash leaf patches" on skin
=cortical and retinal hamartomas + renal cysts
=cardiac rhabdomyomas
Von-Hippel-Lindau Disease
**Associated w/ deletion of VHL gene
=tumor suppressor on chromosome 3p

**See hemangioblastomas of the retina/cerebellum/medulla
=1/2 individuals go on to develop BILATERAL RENAL CELL CARCINOMA
Huntington's Disease
**Triplet repeat disorder (CAG) on chromosome 4
=decreased levels of Ach and GABA in the brain --> caudate atrophy

=depression, progressive dementia, choreiform movements
Familial Adenomatous Polyposis
**Deletion on chromosome 5
=colon becomes covered w/ adenomatous polyps after puberty

**Progresses to colon cancer uncless resected
Hereditary Spherocytosis
=spheroid erythrocytes

=hemolytic anemia, increased MCHC

**Splenectomy curative
Achondroplasia
**AD cell-signaling defect of FIBROBLAST GROWTH FACTOR (FGF) receptor 3

=dwarfism, short limbs BUT head and trunk are normal in size

**Associated w/ advanced PATERNAL age
AR Disorders
=CF, albinism, alpha-1-antitrypsin deficiency, PKU, thalassemias, sickle cell, glycogen storage diseases, mucopolysaccharidoses (except Hunters), sphingolipidoses (except Fabrys), infant polycystic kidney disease, hemochromotosis
Cystic Fibrosis
AR defect in CFTR gene on chromosome 7
=commonly a deletion of Phe508

**Normally, the CFTR channel secretes Cl- in the lungs and GI tract andd reabsorbs Cl from seat
SO, what will a defective Cl-Channel Cause?
**Secretion of abnormally THICK mucus that PLUGS the lungs, pancreas, and liver
--> recurrent pulmonary infections, chronic bronchitis, bronchiectasis, pancreatic insufficiency (malaborption and steatorrhea), + meconium ileus in newborns
What pathogens are CF patients particularly susceptible to?
PSEUDOMONAS

+ staph aureus
Diagnosis?
**Increased concentration of Cl- ions in SWEAT TEST

(most common lethal genetic disease of Caucasians)
Treatment:
N-acetylcysteine to loosen mucous plugs
X-Linked Recessive Disorders
**Be Wise, Fool's GOLD Heeds False Hope**

Bruton's agammaglobulinemia, Wiskott-Aldrich Syndrome, Fragile X, G6PD, Ocular albinism, Lesch-Nyhan syndrome, DMD, Hemophilia A and B, Fabry's Disease, Hunters Syndrome

**Female Carriers are RARELY affected --> random inactivation of X chromosomes in each cell
Fragile X Syndrome
**X-linked defect affeecting the methylation and expression of the FMR1 gene
=chromosome will BREAK when exposed to a folate-depleting substance--i.e. methotrexate--BREAKS at triplet repeats (CGG)

**NOTE that this repeat will show ANTICIPATION
Presentation:
**2nd most common cause of genetic mental retardation
=AFTER DS

=macro-orchidism, long face w/ a large jaw, large everted ears, autism
What are the other trinucleotide repeat diseases?
**Huntington's, myotonic dystrophy, fragile X, friedreich's ataxia

**May show anticipation (=disease severity INCRASES and age of onset DECREASES in sucessive generations)
Autosomal Trisomies
1) DS (Drinking age--21)
2) Edwards Syndrome (Election age--18)
3) Patau's Syndrome (Puberty--13)
Down Syndrome
Trisomy 21
=1:700
=Most COMMON chromosomal disorder and cause of congenital MR
Findings:
=mental retardation
=flat facial profile, prominent epicanthal folds, simian crease
=duodenal atresia
=congenital heart disease
=AD (>35)
=increased risk of ALL
Most common heart malformation
**Septum primum
=ASD due to endocardial cushion defects
Genetics--MOST common cause:
**95% of cases due to meiotic NONDISJUNCTION of homologous chromosomes
=associated w/ advancced maternal age
=1:1500 women <20
=1:25 in women >45
Other causes:
**4% due to Robertsonian Translocation

**1% due to Down Mosaicism
=NO maternal association
Edwards' Syndrome--Genetics:
**Trisomy 18

1:8000

**Death usually within 1 year of birth
Findings:
=severe mental retardation
=rocker bottom feet
=low-set ears + prominent occiput
=micrognathia (small jaw)
=clenched hands
=congenital heart didsease
Patau's Syndrome--Genetics:
**Trisomy 13

1:15,000

**Death usually w/i 1 year of birth
Findings:
=Severe MR
=Micropthalmia and microcephaly
=CLEFT LIP/PALATE
=abornal forebrain structures
=POLYDACTYLY
=congenital heart disease
Cri-du-chat Syndrome
**Cry of the cat**

=Congential DELETION of the short arm of chromosome 5
(46XX or XY, 5p-)
Findings:
=microcephaly
=severe MR
=HIGH PITCHED crying/mewing
=epicanthal folds
=cardiac abnormalities
22q11 Syndromes
CATCH-22 --> microdeletion at 22q11

=cleft palate
=abnormal facies
=thymic aplasia (T-cell deficiency)
=cardiac defects
=hypocalcemia secondary to parathyroid aplasia
SO, how can this present?
**Variable**

1) DiGeorge Syndrome
=thymic, parathyroid, and cardiac defects

2) Velocardiofacial Syndrome
=palate, facial, and cardiac defects
Fetal Alcohol Syndrome
**Newborns of mothers who consumed SIGNIFICANT amounts of alcohol (teratogen) during pregnancy
=highest risk at 3-8 weeks
=inhibits CELL MIGRATION

#1 cause of congenital malformations in the US
Presentation:
=microcephaly, MR
=facial abnormalities
=limb dislocation
=heart and lung fistulas