Practice Questions

Question 1

A 15 y/o girl has developed multiple nodules on her skin over the past 10 years. On PE, there are 20 scattered, 0.3-cm to 1-cm, firm nodules on the pt’s trunk and extremities. There are 12 light brown macules averaging 2-5 cm in diameter on the skin of the trunk. Slit-lamp exam shows pigmented nodules in the iris. A sibling and a parent are similarly affected. Genetic analysis shows a loss of function mutation. Which of the following inheritance patterns is most likely to be present in this family?

A. Autosomal dominant
B. Autosomal recessive
C. Mitochondrial
D. Multifactorial
E. X-linked recessive

Answer 1

A. Autosomal dominant

Question 2

A 22 y/o woman delivers an apparently healthy female infant after an uncomplicated pregnancy. By 4 years of age, the girl has progresive, severe neurologic deterioration. PE shows marked HSM. A bone marrow biopsy specimen shows numerous foamy vacuolated macrophages. Analysis of which of the following factors is most likely to aid in the diagnosis of this condition?

A. Level of alpha-1-antitrypsin in the serum
B. Level of glucose-6-phosphatase in hepatocytes
C. Level of sphingomyelinase in splenic macrophages
D. Number of LDL receptors on hepatocytes
E. Rate of synthesis of collagen in skin fibroblasts

Answer 2

C. Level of sphingomyelinase in splenic macrophages

Question 3

A 10 y/o child has had recurrent otitis media for the past 8 years. On PE, there is HSM. No external anomalies are present. Lab findings include anemia and leukopenia. A bone marrow biopsy is performed [pic in book]. An inherited deficiency of which of the following enzymes is most likely to produce these findings?

A. Alpha-1,4-glucosidase
B. Glucocerebrosidase
C. Glucose-6-phosphatase
D. Hexosaminidase A
E. Lysyl hydroxylase

Answer 3

B. Glucocerebrosidase

Question 4

A 13 y/o boy has been drinking large quantities of fluids and has an insatiable appetite. He is losing weight and has become more tired and listless for the past month. Lab findings include normal CBC and fasting serum glucose of 175 mg/dL. His parents, 2 brothers, and one sister are healthy. A maternal uncle is also affected. Which of the following is the probable inheritance pattern of his disease?

A. Autosomal dominant
B. Autosomal recessive
C. Mitochondria DNA
D. Multifactorial
E. X-linked recessive

Answer 4

D. Multifactorial

Question 5

A healthy 20 y/o woman, G3, P2, Ab1, has previously given birth to a liveborn infant and a stillborn infant, both with the same karyotypic abnormality. On PE, she is at the 50th percentile for height and weight. She has no physical abnormalities noted. Which of the following karyotypic abnormalities is most likely to be present in this woman?

A. Deletion of q arm - del(22q)
B. Isochromosome - 46,X,i
C. Paracentric inversion - inv(18)
D. Ring chromosome - r(13)
E. Robertsonian translocation - t(14;21)

Answer 5

E. Robertsonian translocation - t(14;21)

Question 6

A 27 y/o primigravida has a fetal ultrasound performed at 18 weeks gestation. The male fetus is mildly growth retarded. Multiple congenital anomalies are present including ventricular and atrial septal defects, horseshoe kidney, and omphalocele. Amniocentesis is performed, and the fetal cells obtained are examined using FISH analysis using a probe for one of the chromosomes. Based on the findings shown in the figure, which of the following karyotypic abnormalities is most likely to be present in this fetus?

A. 45,X/46,XX
B. 46,XY,del(22q11)
C. 46,XY,der(14;21)(q10.0),+21
D. 47,XY,+18
E. 47,XXY

Answer 6

D. 47,XY,+18

Question 7

A 27 y/o man and his 24 y/o wife have been trying to conceive a child for 6 years. PE shows he has bilateral gynecomastia, reduced testicular size, reduced body hair, and increased length between the soles of his feet and the pubic bone. A semen analysis indicates oligospermia. Lab studies show increased FSH and slightly decreased testosterone level. Which of the following karyotypes is this man most likely to have?

A. 46,X,i(Xq)
B. 47,XYY
C. 47,XXY
D. 46,XX/47,XX,+21
E. 46,XY,del(22q11)

Answer 7

C. 47,XXY

Question 8

A 25 y/o woman with amenorrhea has never had menarche. On PE, she is 4’9”. She has a webbed neck, broad chest, and widely spaced nipples. Strong pulses are palpable in upper extremities, but there are only weak pulses in lower extremities. On abdominal MRI, her ovaries are small, elongated, and tubular. Which of the following karyotypes is she most likely to have?

A. 45,X/46,XX
B. 46,X,X(fra)
C. 47,XXY
D. 47,XXX
E. 47,XX,+16

Answer 8

A. 45,X/46,XX

Question 9

3 female children in a family arenoted to have histories of multiple fractures along with dental problems and hearing impairment. On exam, they are of normal height and weight for age, but have steel gray to blue sclerae. Both parents are unaffected by these abnormalities. Which of the following genetic abnormalities is most likely to account for the findings in these children?

A. Genomic imprinting
B. Gonadal mosaicism
C. Multifactorial inheritance
D. Random X inactivation
E. Spontaneous new mutation

Answer 9

B. Gonadal mosaicism

Question 10

A study of families with fragile X syndrome reveals that 20% of affected men are carriers but do not develop mental retardation. Genomic sequencing shows that these men have premutations having 55 to 200 trinucleotide repeats in the FMR1 gene. Half of these men exhibit a progressive neurodegenerative disease with cerebellar signs after age 50. Through which of the following mechanisms is their disease mediated?

A. Loss of mRNA transcription
B. Methylation with gene silencing
C. Random inactivation of X chromosome
D. Reduced translation of FMR1 protein
E. Toxicity from gain of function

Answer 10

E. Toxicity from gain of function

Question 11

In a study of inheritance of the CFTR gene, the genetic mutations in carriers and affected individuals are documented. Based on these findings, investigators determine that there is no simple screening test to detect all carriers of mutations of the CFTR gene. Which of the following is most likely to be the greatest limitation to development of a screening test for CFTR mutations?

A. Both copies of the gene must be abnormal for detection
B. Fluorescence in situ hybridization is labor-intensive and expensive
C. Frequency of mutations among ethnic groups limits sensitivity
D. Less than 1 individual in 10,000 is a heterozygote
E. Most mutations cannot be detected by PCR

Answer 11

C. Frequency of mutations among ethnic groups limits sensitivity

Question 12

A 32 y/o woman has had 3 pregnancies, all ending in stillbirths in the first trimester. On PE, she and her only spouse for all pregnancies have no abnormalities. Which of the following lab tests is most appropriate to perform on this woman for elucidating potential causes for recurrent fetal loss?

A. Genome-wide association study
B. Fluorescence in situ hybridization
C. Karyotyping
D. PCR analysis
E. Tandem mass spectroscopy

Answer 12

C. Karyotyping

Question 13

A case-control study is performed involving persons diagnosed with essential hypertension. Genetic analysis reveals linkage disequilibrium. Haplotypes of affected persons differ from the controls in the chromosome containing the angiotensinogen gene. Which of the following types of genetic analysis is most likely to yield this info?

A. FISH
B. Giemsa banded karyotyping
C. RNA expression
D. Single nucleotide polymorphisms
E. Southern blotting

Answer 13

D. Single nucleotide polymorphisms

Question 14

A pedigree reveals that multiple family members over 4 generations have been affected by the onset of CHF within the first four decades of life. A cardiomyopathy is suspected, but specific features of the disease are not known, and no prior genetic testing has been performed. Which of the following techniques involving DNA sequencing is most likely to identify a specific mutation in a cost-effective manner?

A. Pyrosequencing
B. Sanger sequencing
C. Targeted sequencing
D. Whole exome sequencing
E. Whole genome sequencing

Answer 14

D. Whole exome sequencing

Question 15

A 33 y/o man has experienced nausea and vomiting and has become mildly icteric over the past week. On PE his temp is 37.4 C. Labs show serum AST of 208 U/L and ALT of 274 U/L. Serologic findings for HBsAg and HBcAb are positive. A liver biopsy specimen examined microscopically shows focal death of hepatocytes with a portal inflammatory cell infiltrate. Which of the following is the most likely mechanism by which his liver cell injury occurs under these conditions?

A. Activated macrophage cytokine release
B. Ab-mediated destruction of HBsAg-expressing liver cells
C. CD4+ lymphocyte recognition of circulating HBsAg
D. CD8+ lymphocyte recognition of viral peptide presented by MHC class I molecules
E. NK cell recognition of viral peptide presented by MHC class II molecules

Answer 15

D. CD8+ lymphocyte recognition of viral peptide presented by MHC class I molecules

Question 16

A 28 y/o man has had hemoptysis and hematuria for the past 2 days. On PE, his temp is 36.8 C, pulse is 87/min, respirations are 19/min, and BP is 150/90. Lab studies show creatinine of 3.8 mg/dL and urea nitrogen of 35 mg/dL. Urinalysis shows 4+ hematuria, 2+ proteinuria, and no glucose. A renal biopsy specimen examined microscopically shows glomerular damage and linear immunoflourescence with labeled complement C3 and anti-IgG Ab. Which of the following autoantibodies has the greatest specificity for this patient’s condition?

A. Anti-basement membrane
B. Anticardiolipin
C. Anti-double-stranded DNA
D. Antihistone
E. Anti-SS-A
F. Anti-U1-ribonucleoprotein

Answer 16

A. Anti-basement membrane

Question 17

A 26 y/o man has had myalgias and a fever for the past week. On PE, his temp is 38.6 C. He has diffuse muscle tenderness, but no rashes or joint pain on movement. Lab studies show elevated serum creatine kinase and peripheral blood eosinophilia. Larvae of Trichinella spiralis are present within the skeletal muscle fibers of a gastrocnemius biopsy specimen. Two years later, a chest radiograph shows only a few small calcifications in the diaphragm. Which of the following immunologic mechanisms most likely contributed to the destruction of the larvae?

A. Abscess formation with neutrophils
B. ADCC
C. Complement-mediated cell lysis
D. Formation of Langhans giant cells
E. Synthesis of Leukotriene C4 in mast cells

Answer 17

B. ADCC

Question 18

Person with sensitivity to body jewelry undergo skin patch testing with nickel compounds. Within 24 to 48 hours there is focal erythema and induration of their skin, accompanied by itching and pain. Histologically, there is an accumulation of neutrophils and monocytes with some CD4 T cells. Which of the following cytokines produced by T cells is most likely to be involved in mediating this reaction?

A. IL-2
B. IL-5
C. IL-10
D. IL-12
E. IL-17

Answer 18

E. IL-17

Question 19

A 24 y/o woman has had increasing malaise; facial skin lesions are exacerbated by sunlight exposure, and arthralgias and myalgias for the past month. On PE she has mild pedal edema. On auscultation, a friction rub is audible over the chest. Lab findings include pancytopenia and serum creatinine 3 mg/dL. Urinalysis shows hematuria and proteinuria. A serologic test for syphilis yields false positive result. A renal biopsy shows granular deposits of IgG and complement in the mesangium and along the basement membrane. Which of the following mechanisms is most likely involved in the pathogenesis of her disease?

A. Antiphospholipid antibodies
B. Defective clearance of apoptotic nuclei
C. Increased production of IFN-y
D. Molecular mimicry
E. Superantigen activation of T cells

Answer 19

B. Defective clearance of apoptotic nuclei

Question 20

A 29 y/o woman has had fever and arthralgias for the past 2 weeks. On PE she has temp of 37.6 C and an erythematous malar skin rash. Initial lab findings are positive for ANA at 1:1600 and anti-dsDNA Abs at 1:3200, along with false positive serologic test for syphilis. Serum creatinine is markedly elevated, and serum complement levels are decreased. In vitro tests of coagulation (PT and PTT) are prolonged. For which of the following conditions is she at greatest risk?

A. Acute pyelonephritis
B. Cerebral hemorrhage
C. Renal cell carcinoma
D. Malignant HTN
E. Recurrent thrombosis

Answer 20

E. Recurrent thrombosis

Question 21

A 33 y/o woman develops skin rash on her face when she is outside in the sun for more than 1 hour. Lab studies show Hgb 10.2 g/dL; Hct 31.3%; platelet count 126,800/mm3, and WBC count 3211/mm3. Urinalysis shows no glucoe but there is 3+ proteinuria and 2+ blood. Her ANA test result is positive with a titer of 1:2048 and a diffuse homogenous immunofluorescent staining pattern. Which of the following complications is most likely to occur in this patient?

A. Bronchoconstriction
B. Cerebral lymphoma
C. Hemolytic anemia
D. Keratoconjunctivitis
E. Sacroiliitis
F. Sclerodactyly

Answer 21

C. Hemolytic anemia

Question 22

A 31 y/o woman has had increasing peripheral edema, pleuritic chest pain, and an erythematous rash for the past 6 months. Lab studies show increasing serum creatinine, and urinalysis shows proteinuria with RBC casts. A renal biopsy is performed, and the light microscopic appearance of the PAS-stained specimen shows wire-loop glomerular capillary lesions. Which of the following autoantibodies when present is specific for this patients condition?

A. Centromere
B. Cyclic citrullinated polypeptide
C. DNA topoisomerase I
D. Smith
E. U1-RNP

Answer 22

D. Smith

Question 23

A 60 y/o woman exposed to Tb is found to have a positive tuberculin skin test. She receives prophylactic therapy that includes isoniazid. She develops arthralgias, myalgias, and a malar erythematous rash 9 months later. Lab findings include ANA titer of 1:2560 in a diffuse pattern. Anti-dsDNA Abs are not present. Which of the following autoantibodies has greatest specificity for her condition?

A. Anti-Sm
B. Anticentromere
C. Antihistone
D. Anti-Jo-1
E. Anti-U1-ribonucleoprotein
F. Anti-SS-A

Answer 23

C. Antihistone

Question 24

A 19 y/o woman has a skin rash involving her face and scalp for the past 9 months. On exam there are 0.5 to 1.5cm plaques with erythema and edema. A punch biopsy is taken and on microscopic exam shows follicular plugging. There is positive immunofluorescence at the dermal-epidermal junction with staining for IgG and complement C3. Which of the following pathogenic mechanisms result from TLR engagement by self nucleic acids?

A. Mast cell degranulation
B. Molecular mimicry
C. Release of sequestered Ags
D. Th17 elaboration
E. Type I IFN elaboration

Answer 24

E. Type I IFN elaboration

Question 25

During heterosexual intercourse, seminal fluid containing HIV contacts vaginal squamous mucosa. Cells capture virions and transport the virus via lymphatics to regional lymph nodes. Within the germinal centers of these lymph nodes, the virons infect CD4+ cells and proliferate, causing CD4+ lysis with release of more virions, which are taken up on the surface of cells having Fc receptors, allowing continued infection by HIV of more CD4+ cells passing through the nodes. Which of the following types of cells is most likely to capture HIV on its surface via Fc receptors?

A. B lymphocyte
B. CD8+ cytotoxic lymphocyte
C. Follicular dendritic cell
D. Natural killer cell
E. Langhans giant cell
F. Macrophage
G. Mast cell

Answer 25

C. Follicular dendritic cell

Question 26

A 51 y/o woman has had bilateral diffuse pain in her thighs and shoulders for the past 6 weeks. She has difficulty rising from a chair and climbing steps. She has a faint violaceous rash around the orbits and on the skin of her knuckles. On PE, she is afebrile. Muscle strength is 4/5 in all extremities. Lab studies show serum creatine kinase of 753 U/L and the ANA test result is positive with a titer of 1:160. Which of the following serologic tests is most specific for the diagnosis of her underlying condition?

A. Anti-cyclic citrullinated peptide
B. Anti-double-stranded DNA antibodies
C. Antihistone antibodies
D. Anti-Jo-1 antibodies
E. Anti-U1-ribonucleoprotein antibodies

Answer 26

D. Anti-Jo-1 antibodies

Question 27

A 4 y/o previously healthy boy has had pharyngitis with fever and malaise for a week. On PE he has lymphadenopathy and HSM. Serologic studies demonstrate the presence of EBV infection. Flow cytometry shows presence of NK cells, but they are found to be nonfunctional when tested in vitro. There is hypogammaglobulinemia. He develops B cell non-Hodgkin lymphoma. His 2 y/o brother follows a similar course starting at age 5. Which of the following immunologic conditions best explains his findings?

A. DiGeorge syndrome
B. HIV infection with AIDS
C. Severe combined immunodeficiency
D. Wiskott-Aldrich syndrome
E. X-linked lymphoproliferative disorder

Answer 27

E. X-linked lymphoproliferative disorder

Question 28

A 4 y/o boy has had recurrent respiratory infections with multiple bacterial and viral pathogens for the past 3 years. On PE, he has eczema involving the trunk and extremities. Serum immunoglobulin levels show normal IgG, low IgM, and high IgA. This patient is at increased risk for which of the following?

A. Dementia
B. Hypocalcemia
C. Glomerulonephritis
D. Malignant lymphoma
E. Rheumatoid arthritis

Answer 28

D. Malignant lymphoma

Question 29

A 28 y/o woman with a 9-year history of IV drug use has developed chronic watery diarrhea that has persisted for the past week. On PE she is afebrile and has mild muscle wasting. Her BMI is 18. Lab studies of her stool show cysts of cryptosporidium parvum. One month later, she develops cryptococcal meningitis, which is treated successfully. Oral candidiasis is diagnosed 1 month later. This patient is at greatest risk of developing which of the following neoplasms?

A. Cerebral astrocytoma
B. Cervical clear cell carcinoma
C. Cerebral non-Hodgkin lymphoma
D. Pulmonary adenocarcinoma
E. Retroperitonal sarcoma

Answer 29

C. Cerebral non-Hodgkin lymphoma