Question 1
Question
All of the following about hereditary breast and ovarian cancer are true except?
Answer
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Autosomal recessive inheritance
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BRCA 1 and BRCA 2 normally maintain genomic integrity by acting as a tumor suppressor gene and regulating DNA repair, transcription transactivation and the cell cycle
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2 hit hypothesis- Somatic LOF by the second allele occurs by loss of heteozygosity, intragenic mutation or promoter hypermethylation
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Founder effect seen in Ashkenazi Jews
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Germ line mutation of BRCA2 is associated with male breast cancers (6-14%)
Question 2
Question
Familial hypercholesterolemia is characterized by all of the following except?
Answer
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Autosomal Dominant inheritance
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Mutation of LDL receptor found in 59% of French Canadian with familial hypercholesterolemia
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LDL-R binds apoB100 and apoE
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decreased LDL cholesterol
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Management is mainly low fat high carbohydrate diet with 3 classes of drugs: bile sequestrants (Cholestyramine resin), HMG CoA reductase inhibitors and nicotinic acid
Question 3
Question
All of the following about G6PD deficiency are true except
Answer
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X-linked recessive inheritance
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G6PD is the first enzyme in HMP shunt critical for generating NADPH which is required to regenerate glutathione
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Rare symptomatic females - due to skewing of X chromosome inactivation
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G6PD B- is less severe than G6PD A-
Question 4
Question
A 25 year old African-American man is given anti-malarial prophylaxis for a trip to West Africa. Over the next week he develops increasing fatigue. On Physical exam there are no abnormal findings. Lab studies show a hematocrit of 30% and peripheral blood smear shows red blood cells with numerous Heinz bodies. There is a family history of this disorder, with males but not females, affected. What is the most likely diagnosis
Question 5
Question
A 30 year old woman has felt a mass in her right breast for 6 months. On physical exam there is a 5 cm mass in the right breast and it is firm, non tender with lymphadenopathy. A fine needle aspiration is performed and cytologic exam shows carcinoma cells. Right mastectomy with axillary lymph node dissection is performed and microscopic exam shows a poorly differentiated carcinoma that is negative for estrogen and progesterone receptors and negative for HER2/neu. One axillary node shows micrometastases. Her 32 year old sister is found to have a similar lesion. Which is the following is the most likely risk factor for this woman's breast cancer?
Answer
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BRCA 1 mutation
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loss of p53
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Both of the above
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none of the above
Question 6
Question
All of the following about Hereditary hemochromatosis are correct except
Answer
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Autosomal recessive with reduced penetrance
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HFE mutation
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90-95% of patients are homozygous for a Cys282Tyr mutaion
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Mutant HFE interferes with hepcidin signaling resulting in stimulation of enterocytes and macrophages to release iron
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Hepcidin is synthesized in liver and released to block further iron absorption when iron supplies are adequate
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Males are protected against this condition
Question 7
Question
46 year old man who has had worsening arthritis and swelling of his feet for the past year. On exam he has rales audible in all lung fields. A CXR showed cardiomegaly and pulmonary edema. Lab studies showed Hgb of 13, Hct of 39.1% MCV 86fl, platelet count of 255,000/ul and WBC count 5920/ul. His serum iron is 406 microgram/ml, with iron binding capacity of 440 micrograms/ml and ferritin 830 ng/ml. What is the most likely diagnosis
Question 8
Question
All of the following about Hemophilia are true except?
Answer
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Both Hemophilia A and B are X-linked recessive
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Factor 9 - Most common mutation is an inversion deleting the carboxyl terminus of factor 9
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Factor 9 - severe hemophilia during childhood that spontaneously resolves at puberty as factor 9 levels nearly normalize
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Therapy is replacement of the factor that is deficient
Question 9
Question
All of the following regarding HPNCC are true except
Answer
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Autosomal Dominant inheritance
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Mutation in MLH1, MSH2) DNA mismatch repair gene mutation
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Microsatellite instability occurs in 15-20% of HNPCC tumors
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Microsatellite instability induced frame shift mutations in the transforming growth factor receptor II gene (TGFBetaR2)
Question 10
Question
All of the following are true regarding NIDDM except?
Answer
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Multifactorial inheritance
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TCF7L2 significantly associated with NIDDM in Icelandic population and Pro12Ala mutation in PPARG in Finnish and Mexican Americans
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More prone to develop ketoacidosis
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HbA1c > 6.5% is more important that the actual glucose levels
Question 11
Question
A 57 year old man is found comatose. On exam he has decreased skin turgor. Lab studies show a blood glucose of 780 mg/dl. Urinalysis reveals no ketosis or proteinuria, but there is 4+ glucosuria. What is the most likely diagnosis?
Question 12
Question
24 hour old male baby is comatose and on lab studies shows Hyper ammonia, hypo citrullemia and urine showed orotic aciduria. Most likely diagnosis
Answer
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CPS I deficiency
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CPS II deficiency
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OTC deficiency
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None of the above
Question 13
Question
All of the following are true about Retinoblastoma except?
Answer
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Autosomal Dominant - LOF mutation on chromosome 13
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Isodisomy is the most common type of mutation
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Nearly half the mutations occurs at CpG dinucleotides (C --> T transition)
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Unilateral disease in hereditary
Question 14
Question
All of the following for Tay-Sachs disease are true except?
Answer
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Autosomal recessive inheritance
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Hexosaminidase A is a lysosomal enzyme made of HEXA + HEXB genes, Hexosaminidase A in the presence of activator protein, removes the N-terminal GalNAc from the ganglioside
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Curable disorder
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Infantile - onset is characterized by neurological deterioration at 3-6 months of age and Juvenile onset usually manifests between 2-4 yrs of age and also characterized by neurological deterioration
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Have normal levels of hexosaminidase B