Chapter 6 Q&A

Question 1

1. 4 yo girl presents for PE; small head circumference, thin upper lip, low-bridge nose; mild mental retardation; parents state she is often emotional; what defects account for findings?

Answer 1

Alcohol abuse (fetal alcohol syndrome with growth retardation, CNS dysfunction, facial dysmorphology)

Question 2

2. 12 mo boy goes to ER and there is recent fracture of right ulna and healing fractures; blue sclerae; patient has mutation with which proteins?

Answer 2

Collagen (osteogenesis imperfecta, or brittle bone disease; the fragility of bone due to type I collagen synthesis affected)

Question 3

3. 28 yo woman has stillborn with neural tube defect; defect caused by error of morphogenesis that occurred at which stage of development?

Answer 3

20-40 days (dysfunction of the neural tube to close around day 23-26 of gestation)

Question 4

4. 20 yo man has numerous pigmented patches and pedunculated skin tumors on chest; benign neoplasm from Schwann cells; parents don’t have signs; what is the mutation for?

Answer 4

GTPase activating protein: neurofibromatosis type 1 characterized by disfiguring neurofibromas, areas of dark pigmentation of skin, pigmented lesions of the iris; the GTPases inactivate ras protein

Question 5

5. Patient with pigmented patches is at increased risk of developing which neoplasm?

Answer 5

Neurofibrosarcoma (a complication of neurofibromatosis type 1)

Question 6

6. 25 yo pregnant woman, 16 weeks gestation; US shows 3 cm neural tube defect in thoracic spine; what would screening test measure for in the serum?

Answer 6

Alpha-fetoprotein (AFP): will enable detection of all anencephalic features

Question 7

7. 25 yo man presents as tall, long fingers; later has dissecting aortic aneurysm; what mutation is here?

Answer 7

Fibrillin: missense mutation in gene for fibrillin leads to Marfan’s

Question 8

8. What is pattern of inheritance with Marfan’s?

Answer 8

Autosomal dominant

Question 9

9. 12 mo boy shows progressive weakness, mental deterioration, loss of vision; labs show decreased hexosaminidase A; child becomes blind and dies at 3 years of age; what is the path?

Answer 9

Accumulation of unmetabolized substrate

Question 10

10. Parents of kid with hexosaminidase A deficiency have four sons, two daughters, how many of their children expected to be asymptomatic?

Answer 10

3 (Tay-Sachs is autosomal recessive, so half expected to be asymptomatic)

Question 11

11. 4 yo boy has pneumonia and respiratory distress; bowel movements are greasy and have pungent odor; sweat-chloride test positive; why the steatorrhea?

Answer 11

Lack of pancreatic enzyme secretion (CF characterized by chronic pulmonary disease, deficient exocrine pancreatic function, and other complications of inspissated mucus in number of organs)

Question 12

12. For 4 yo boy with pneumonia and respiratory distress, what mutations are expected?

Answer 12

Membrane ion channel (Cl)

Question 13

13. 10 yo child presents with xanthomas on extensor surfaces of forearms; labs show cholesterol of 820 mg/dL; child’s mother and maternal grandfather with elevated serum cholesterol; where is the mutation?

Answer 13

LDL receptor

Question 14

14. 10 mo boy is fair skinned, blond hair; has mousy odor; inborn error of aa metabolism; to prevent mental retardation, what aa’s should be lacking?

Answer 14

Phenylalanine (PKU with autosomal recessive disease and mental deterioration)

Question 15

15. What is the path for the 10 mo fair skinned kid?

Answer 15

Accumulation of unmetabolized substrate

Question 16

16. 4 yo boy with pliable skin; bruises easily; joints hyperextended; deficiency of lysyl hydroxylase; what is the abnormal cell/tissue component?

Answer 16

Collagen fibers: Ehler Danlos (autosomal dominant, type IV)

Question 17

17. 25 yo woman with recurrent bone pain, increasing abdo girth; massive hepatosplenomegaly; radiolucent bone defects; large cells with fibrillar appearance reminscent of wrinkled tissue paper; where is the mutation?

Answer 17

Glucosidase (Gaucher disease, with Gaucher cells that have lipid-laden macrophages seen in red pulp of spleen, liver sinusoids, lymph nodes, lungs, and bone marrow)

Question 18

18. How do you get hepatosplenomegaly, bone pain in 25 yo woman?

Answer 18

Accumulation of unmetabolized substrate

Question 19

19. Neonate with severe motor dysfunction of lower extermities; vertebral bodies in lumbar region lack posterior arches; space under membrane has tissue with meninges and spinal cord; what can reduce incidence of neural tube defects?

Answer 19

Folic acid

Question 20

20. Parents of infant with cleft lip and palate; what can cause this error of morphogenesis?

Answer 20

Structural chromosomal abnormality (multifactorial inheritance, teratogens also causes of the cleft lip and palate)

Question 21

21. 4 yo boy has weakness in pelvic and shoulder girdles and calf muscle enlarged; CK levels elevated; foci of muscle fiber necrosis, myophagocytosis, regenerating fibers, fibrosis; where would there be alterations of the primary transcript?

Answer 21

Dystrophin (DMD, a severe X0linked condition with degeneration of the muscles)

Question 22

22. What can cause patient death from DMD?

Answer 22

Cardiomyopathy

Question 23

23. 22 yo man complains about inability to conceive child; patient is tall, gynecomastia and testicular atrophy; incrased levels of FSH; chromosomal abnormality?

Answer 23

Meiotic nondisjunction (Klinefelter syndrom, or testicular dysgenesis, usually involving one extra X chromosome, ie XXY)

Question 24

24. 35 yo pregnant woman has baby prematurely at 28 weeks gestation; neonate becomes SOB, with intercostal retraction and nasal flaring during respiration; dies of respiratory insufficiency and intraventricular hemorrhage; what is the eosinophilic material?

Answer 24

Fibrin (respiratory distress syndrom and deficiency of surfactant; collapse of alveoli)

Question 25

25. If neonate with RSD had survived, which would have led to anoxia and acidosis?

Answer 25

Necrotizing enterocolitis: most common acquired gastrointestinal emergency in newborns and thought to be related to ischemia of intestinal mucosa

Question 26

26. 16 yo girl is not menstruating; patient short, thick-webbed neck; widely spaced nipples and poor breast development; if caused by nondisjunction during mitosis of somatic cell, what is the karyotype?

Answer 26

45,X/46,XX: woman with Turner syndrome having mosaics rather than lacking an entire X chromosome

Question 27

27. 34 yo woman has female neonate with generalized edema and jaundice; CBC shows hemolytic anemia; Rh-incompatibility seen; which crossing leads to anasarca and jaundice in neonate?

Answer 27

IgG

Question 28

28. Parents of 2 yo boy with hyposadias (urethra opens on ventral aspect of penis); what pattern of inheritance?

Answer 28

Multifactorial:

Question 29

29. 42 yo woman gives birth to neonate with multiple congenital abnormalities: flat facial profile, slanted eyes, epicanthal folds, Brushfield spots, short nose, short neck, dysplastic ears, clinodactyly, large protruding tongue, heart murmur; cause?

Answer 29

Nondisjunction: trisomy 21/Down syndrome

Question 30

30. In adulthood, patient with Down syndrome has what changes?

Answer 30

Alzheimer disease

Question 31

31. 50 yo man with history of type 2 DM asks about inheritance pattern?

Answer 31

Multifactorial

Question 32

32. 25 yo man with autism and mental retardation history; has coarse facial features, increased head circumference, macro-orchidism; maternal uncle affected; fragile X syndrome rendered; cause?

Answer 32

Expansion of trinucleotide repeat

Question 33

33. 28 yo man presents to ER after experience crushing substernal chest pain; acute MI; later dies of cardiac arrhythmia; how?

Answer 33

Familial hypercholesterolemia (leading to accelerated atherosclerosis; due to mutations of gene encoding LDL receptor)

Question 34

34. 5 yo boy with maculopapular rash; rash affects palsm and soles; cracks and fissures around mouth and anus; interstitial keratitis; mild hepatosplenomegaly; anterior tibial bones with outward curvature; cause?

Answer 34

Syphilis: TORCH (toxoplasma, rubella, cytomegalovirus, herples, others, including congential syphilis); notice the rash early on

Question 35

35. 3 yo boy dies in auto accident; right lung shrunken, right main stem bronchus ends in nondescript tissue with rudimentary ducts and CT; error?

Answer 35

Aplasia: absence of organ coupled with persistence of the organ anlage or a rudiment

Question 36

36. Mother of newborn boy sees him vomit every feeding; esophagus almost completely occluded; why?

Answer 36

Atresia

Question 37

37. 87 yo woman dies in sleep: pancreatic tissue seen in wall of lower esophagus; why?

Answer 37

Choristomas: minute or microscopic aggregates of normal tissue in aberrant locations Hamartomas: focal, benign overgrowths of one or more of the mature cellular elements of a normal tissue Hemangiomas: most frequently encountered tumors in childhood

Question 38

38. 30 yo pregnant woman says two of three kids with yellow jaundice at birth; mother blood type O, Rh neg, husband blood type A, Rh positive; what was most likely used as indicator of fetal lung maturity?

Answer 38

Lecithin: made by type II pneumocytes; check to see that ratio is above 2:1 relative to sphingomyelin to see if they survive without respiratory distress syndrome

Question 39

39. That 30 yo pregnant woman has kid with severe generalized edema; baby dies even with transfusions; why the anasarca?

Answer 39

Erythroblastosis fetalis (CHF): hemolytic disease of newborn caused by maternal Ab's against fetal erythrocytes

Question 40

40. An 18 yo woman gives male neonate; baby with cephalohematoma and also subperiosteal hemorrhage over calvarial bones; what is outcome of this tough delivery and labor?

Answer 40

Spontaneous resolution

Question 41

41. 42 yo woman in third pregnancy has female neonate at 30 weeks gestation; baby with jaundice within 2 days; unconjugated serum bilirubin 15 mg/dL; what is most serious complication of untreated hyperbilirubinemia in this neonate?

Answer 41

Encephalopathy (Kernicterus)

Question 42

42. 27 yo woman presents for pregnancy test; what is consequence of toxic exposure to conceptus during early development (heavy drinking)?

Answer 42

Embryonic lethality