Usmle-First Readings

Front 1

Patients presents with dwarfism, short limbs, but head and trunk are normal size. What molecule is defective?

Back 1

Achondroplasia

Defect in FGF receptor

Front 2

LoH, which disease manifests?

Back 2

Rb = retinoblastoma

What is LoH?
When there's a mutation in a tumor suppressor gene, the complementary allele must be deleted/mutated before cancer develops.

Front 3

Pt. presents with acute loss of central vision. Her mom had it too. What is disease mode of inheritence?

Back 3

Dx. Leber's hereditary optic neuropathy

Mode of inheritence : Mitochondrial inheritance

Front 4

See genu varus, what is disease mode of inheritance?

Back 4

Bow legged ==> Ricket's, so X-linked DOMINANT

Front 5

Patients presents with dwarfism, short limbs, but head and trunk are normal size. What molecule is defective?

Back 5

Dx: Achondroplasia

Defect in FGF receptor

Front 6

What is Be Wise Fool's GOLD Heeds Silly Hope?

Back 6

X linked recessive disorders:

B= bruton's agammaglobinemia
W= wiskott-aldrich ( triad: eczema, thrombocytopenia,immunodeficiency)
F = Fabry's dz

G = G6PD deficiency
O = ocular albinism
L = Lesch-Nyhann
D = Duchenne Muscular Dystrophy

HS = Hunter's Syndrome

H = Hemophilia A and B

Front 7

What are the nucleotide repeats for the following trinucleotide repeat disorders?

1. Huntington's Disease
2. Myotonic Dystrophy
3. Fragile X syndrome
4. Friedrich's Ataxia

Back 7

1. CAG
2. CTG
3. CGG
4. GAA ( GAAAA, my ataxia!)

Front 8

What two diseases are Down's kids most likely to get?

Back 8

1. ALL ( MAJOR $$)
2. Alzheimer's

Front 9

What are the findings in a Down's positive pregnancy screen?

Back 9

A, B , E, I
down ,up, down, up

alpha- feto protein ( AFP ) low
Beta- hCG ( high)
estriol ( low)
inhibin A ( high)

Front 10

Patient presents with lesions on lips, and also corneal vascularizaiton. What vitamin is this person deficient in?

Back 10

Vitamin B2
( B2, 2 syllables ( Ri-Bo), and 2 C's = Cheliosis and Corneal vascularization, FADH2**).

Front 11

Patient presents with skin lesions, diarrhea, and confusion. What amino acid is deficient?

Back 11

Patient has pellagra

Niacin is deficient vitamin

( need tryptophan to make NAD+, NADP+ from niacin).

Low Tryptophan absorption = Hartnup disease

High metabolism of tryptophan = carcinoid syndrome (FA 302)

Another cause could be INH, which blocks vitamin B6. B6 is necessary for the synthesis of niacin from tryptophan

Front 12

Patient presents with fatigue, + Schilling test, and see macrocytic, megaloblastic anemia. What enzyme is non-functional?

Back 12

Dx: Pernicious anemia
Lack of IF, and lack of B12

B12 is Cofactor for
Homocysteine methyltransferase. FA 92

Front 13

What's the difference between megaloblastic anemias between B12 deficiency and Folate deficiency?

Back 13

Folate deficiency has no NEURO symptoms. FA 92

Front 14

Deficiency in Vit E, can cause demyelination in which part of the spinal cord?

Back 14

posterior column and spinocerebellar tracts FA 93

Front 15

Patient has AGMA, breath smells sweet, seems intoxicated. What is the antidote?

Back 15

He has ethylene glycol poisoning

Antidote: Fomepizole

Front 16

Patient develops vomiting, has rice water stools, and a tinge of garlic smelling breath. The toxin suspected acts to block which factor?

Back 16

Arsenic Poisoning:
Headache, confusion, diarhhea rice water stools, vomiting, lactic acidosis.

Arsenic blocks Pyruvate Dehydrogenase Complex which has 3 enzymes, 5 cofactors:

TPP- pyrophosphate ( B1- Thi)
FAD ( B2- Ri-BO)
NAD ( B3- NI- A- CIN)
CoA ( B5- pantothenate)
Lipoic acid

Arsenic blocks LIPOIC ACID ( answer)

Front 17

How do you great PDH deficiency?

Back 17

Increase intake of ketogenic amino acids:

( Lysine and Leucine)

Front 18

Patient has hx of hepatitis, he presents with tremor, slurred speech, vomiting, blurry vision. What is the treatment to alleviate his symptoms?

Back 18

Dx:He has hyperammonemia
Sx: Tremor, slurred speech, somnolence, vomiting, cerebral edema, blurred vision

Liver disease or Urea Cycle enzyme deficiency can cause this.

Hyperammonemia increases NH4+ and depletes alpha-ketoglutarate, which blocks the TCA cycle

Tx: Decrease protein intake, + Benzoate and phenylbutyrate to lower ammonia levels.