Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
44 Cards in this Set
- Front
- Back
|
C2. Guanine nucleotide binding proteins play regulatory role in many signal transduction pathways within the cell. Abnormalities of guanine nucleotide binding protein have been associated with several clinical disorders. Which of the following disorders results from inactivating mutations of the guanine nucleotide binding protein Gs?
A. Albright hereditary osteodystrophy B. insulin unresponsiveness C. McCune-Albright syndrome D. nephrogenic diabetes insipidus E. type II diabetes mellitus |
Answer: A. Mutations causing deficiency of G proteins occur in Albright osteodystrophy while activating mutations in the same gene cause McCune-Albright.
|
|
|
C3. An infant dies at ten days of age, and autopsy reveals clinical features that include: agyria, cerebellar hypoplasia, Dandy-Walker cyst, microphthalmia, and retinal detachment with retinal dysplasia. Which of the following syndromes if the most likely diagnosis?
A. Meckel-Gruber syndrome B. Miller-Dieker syndrome C. Neu-Laxova syndrome D. Pallister-Hall syndrome E. Warburg syndrome |
Answer: E. This is a typical description for a patient with Warburg syndrome. A patient wlth Meckel-Gruber syndrome would more likely have encephalocele, polydactyly, and polycystic kidney disease. The Pallister-Hall syndrome is characterized by hypothalamic hamartoblastoma, hypopitutarism, imperforate anus, and postaxial polydactyly. The Neu-Laxova syndrome is characterized by microcephaly or lisssencephaly, elfin-facies with exophthalmos, and syndactyly with subcutaneous edema. The Miller-Dieker syndrome is characterized by lissencephaly.
|
|
|
C4. Prader-Willi is a genetic syndrome characterized by failure to thrive during the first year of life, developmental delay in most patients, small hands and feet (more noticeable in late childhood), crytorchidism in males, a facial gestalt that is recognizable in many patients and food- seeking behaviour after age two. Even so clinical diagnosis can be difficult because of the variability in the phenotype and laboratory studies have become the mainstay of diagnosis. Which of the following laboratory analyses is most likely to reveal a positive finding in a young child where the constellation of clinical features above is not readily identifiable?
A. FISH analysis for missing SNRPN locus B. High-resolution chromosome analysis C. Imprinting assessment with DNA methylation assay D. Routine chromosome analysis and karyotype E. Subtelomeric probe analysis by FISH studies |
Answer C. Consensus clinical diagnostic criteria are accurate, but the mainstay of diagnosis is DNA-based methylation testing to detect abnormal parent-specific imprinting within the Prader-Willi critical region (PWCR) on chromosome 15, this testing determines whether the region is maternally inherited only (i.e., the paternally contributed region is absent) and detects more than 99% of affected individuals. Methylation-specific testing is important to confirm the diagnosis of PWS in all individuals, but especially those who have atypical findings or are too young to manifest sufficient features to make the diagnosis on clinical grounds.
|
|
|
C1. A concerned mother brings her 18-month-old daughter to the pediatrician's office because she has been intermittently constipated. Her mother became alarmed while changing her diaper straining to have a stool, she found some red, tissue bulging from the rectum. Which of the following procedures or laboratory studies is most like to identify the appropriate diagnosis?
A. Colonoscopy for Crohn disease. B. Molecular analysis for Duchenne muscular dystrophy C. Rectal biopsy Hirschsprung disease D. Renal ultrasound for Beckwith-Wiedemann syndrome |
Answer: E. Rectal prolapse is a frequent feature of CF and should raise concern about that diagnosis.
|
|
|
C5. A newborn infant has the Robin sequence. The mother was diagnosed with arthritis in childhood and has had a retinal detachment. Which of the following is the most likely syndromic diagnosis?
Acromesomelic dysplasia Rieger syndrome Stickler syndrome Treacher Collins syndrome Warburg syndrome |
Answer: C. This would be a reasonably good story for Stickler syndrome. The arthropathy can simulate juvenile rheumatoid arthritis. Retinal detachment is a feature. Robin sequence can occur in childhood. The other disorders would all be quite different.
|
|
|
C6. Radial ray anomalies distinguished by the presence or absence of thumbs can provide a clue
toward an appropriate diagnosis. In which of the following syndromes are thumbs consistently present? Thrombocytopenia and absent radius syndrome Fanconi anemia Holt-Oram syndrome VATER association de Lange syndrome |
Answer: A. The thumbs may be absent in any of these disorders except TAR where they are consistently present.
|
|
|
C7. Soft cystic masses in the auricle which develop into hypertrophic cartilage are a typical feature of which of the following skeletal dysplasias?
Achondroplasia Camptomelic dysplasia Chondroectrodermal dysplasia Diastrophic dwarfism Larsen syndrome |
Answer: D. This description of the changes in the ear is typical of diastrophic dwarfism. It is a very distinctive change but is usually not present in the neonatal period.
|
|
|
C8. A 28-year-old woman underwent amniocentesis for chromosomal analysis when her fetus was
found to have limbs that were short for the assigned dates. The karyotype was 46,XY. At birth the baby had female appearing genitalia. These clinical findings are most consistent with which of the following syndromes? Achondrogenesis type IA Achondrogenesis type II Campomelic dysplasia Jeune thoracic dystrophy Thanatophoric dysplasia |
Answer: C. Female appearing genitalia in an XY infant is a common feature of campomelic dysplasia, but is not a feature of the other disorders.
|
|
|
C9. A 1-year-old boy presents with an episode of fever on a 90 degree day in July and there is no evidence of an infection. His parents note that he never seems to sweat in the extreme heat of the summer. He has extremely sparse hair. Skull x-rays show absence of most of the primary tooth buds. Which of the following statements reflects the most likely inheritance pattern for this disorder?
A. He likely has an autosomal dominant disorder. B. He likely has an autosomal recessive disorder. C. He likely has a sporadically occurring disorder. D. He likely has an X-linked dominant disorder. E. He likely has an X-linked recessive disorder |
Answer: E. This clinical description is very suggestive of anhidrotic ectodermal dysplasia, which is usually X-linked. Many other forms with different inheritance occur. This story is typical for the X-linked disorder but is not diagnostic of that pattern of inheritance.
|
|
|
C10. A newborn infant has extreme hypotelorism, microcephaly, midline cleft, poor temperature regulation, seizures, and no anomalies below the neck. Which of the following syndromes is best described by these findings? A. Ellis van Creveld syndrome B. Holoprosencephaly C. Meckel-Gruber syndrome D. Trisomy 13 E. Trisomy 18
|
Answer: B. This is a typical description of holoprosencephaly. The trisomies and Meckel-Gruber syndrome would likely be associated with additional features below the neck. The CNS abnormalities would not be a feature of Ellis van Creveld although cardiac defect and limb abnormalities would be present.
|
|
|
C11. A newborn infant has cleft lip and palate, postaxial polydactyly, microphthalmos, and congenital heart disease. Which of the following syndromes is best described by these findings?
A. Ellis van Creveld syndrome B. Holoprosencephaly C. Meckel-Gruber syndrome D. Trisomy 13 E. Trisomy 18 |
D
|
|
|
C12. Haploinsufficiency is the mechanism underlying the genotype/phenotype relationship for which of the following disorders? A. achondroplasia B. acute intermittent porphyria C. Huntington disease D. multiple endocrine neoplasia, type 2A E. transthyretin amyloidosis
|
Answer: B. All the conditions listed are autosomal dominant disorders. Missense mutations with some type of aberrant function are involved in MEN2A and achondroplasia. The mechanism is not clear for Huntington disease, but there is no evidence that deletion of this region causes the disease, and the evidence favors some type of gain of function. A harmful effect of the mutant protein is involved in amyloidosis. Many of the mutations in acute intermittent porphyria and in some of the other porphyries are obvious loss of function mutations indicating that haploinsufficiency is the mechanism of dominance for AIP.
|
|
|
C13. Reproductive fitness is a measure of an individual’s likelihood of being able to have offspring where a fitness level of 1 is equivalent to the normal population and a fitness of 0 represents an inability to reproduce. In the relationships outlined below the disorders are abbreviated as follows: Huntington disease (HD), tuberous sclerosis (TS), neurofibromatosis type 1 (NF), and osteogenesis imperfecta type II (OI). What relationship best describes the reproductive fitness of these disorders from greatest to least?
|
HD>NF>TS>OI
|
|
|
C14. A six-year-old girl presents to clinic with a history of cleft palate, tetralogy of Fallot, height at the 3rd centile, and mental retardation. Which of the following syndromes is the most likely diagnosis?
A. Cardiofaciocutaneous syndrome B. Down syndrome C. Otopalatodigital syndrome D. Stickler syndrome E. Velocardiofacial syndrome |
E. Conotruncal defects are most common in Down syndrome and clefting would be less typical. It is unlikely a child with Trisomy 13 or 18 would survive to age 6 years. Congenital heart defect would not be expected with otopalatodigital syndrome and it is much less common than VCFS. Clefting and TOF are not features of CFC. All of the features listed are common in VCFS.
|
|
|
C15. A 7-year-old boy with cleft palate, height at the 3rd centile, myopia, and a family history of retinal detachment presents to orthopedic clinic with hip pain and a referring diagnosis of Legg-Perthes disease. Which of the following syndromes is most consistent with this patient’s clinical presentation?
A. Coincidental Legg-Perthes disease in a child with nonsyndromic cleft palate B. Otopalatodigital syndrome C. Stickler syndrome D. Struger’s multiple epiphyseal dysplasia with cleft palate syndrome E. Velocardiofacial syndrome |
Answer: C. The retinal detachment is the unique feature in this question- it is only found in Stickler syndrome.
|
|
|
C16. A newborn baby is found to have hydrocephalus, spina bifida, and clubbed feet. Which of the following genetic etiologies provides the best description of this baby’s clinical features?
A. A multiple congenital anomalies syndrome B. A single primary malformation C. A probable teratogenic syndrome D. A probable chromosome abnormality E. An association |
Answer: B. This is a single primary malformation because the other malformations are a direct result of the first. A MCA syndrome includes anomalies that arise independently, not causatively. An association is a group of anomalies that frequently arise together (e.g. VACTERL) without an apparent relationship to each other or a known single gene cause. The vast majority of neural tube defects are isolated and multifactorial in origin, not chromosomal or teratogenic.
|
|
|
C17. You are evaluating a newborn with bilateral absence of the radii, with intact thumbs. Which of the following clinical findings is most likely to be associated with this baby’s presentation?
A. Cytogenetic testing would show an extra copy of an E group chromosome. B. Hypoplasia of the mammary tissue is a common associated finding. C. Thrombocytopenia is a common complication. D. Tracheo-esophageal fistula is a common associated finding. E. When DEB is added to the media, increased chromosomal breakage is seen. |
Answer: C. Absent radii is associated with absent or abnormal thumbs except in one syndrome- Thrombocytopenia-Absent Radius syndrome. These children have a high rate (as the name suggests) of developing thrombocytopenia. The other answers suggest other syndromes that commonly manifest radial hypoplasia, but in all the thumbs are also absent: Trisomy 18 (answer B), Fanconi syndrome (answer D), and VATER (answer E). Answer C suggests ulnar mammary syndrome, in which ulnar ray (not radial ray) defects are associated with mammary hypoplasia.
|
|
|
C18. A child with hypoplastic left heart syndrome is being evaluated prior to consideration of a heart transplant. Which of the following karyotypes is most likely to be found on chromosomal analysis?
A. 45,X B. 46,XX C. 46,XX,del(22)(q11.2q11.2) D. 46,XY.ish del(7)(q11.23q11.23)(ELN-) E. 47,XXY |
Answer: B. The most common cytogenetic finding seen with hypoplastic left heart (HLH) is a normal karyotype. Turner syndrome (45,X) is among the most common cytogenetic abnormalities seen with HLH, but is still not as common as a normal karyotype. Other syndromes seen with HLH include Down syndrome, and Smith Lemli Opitz.. HLH is not seen at an increased frequency in Williams syndrome [46,XY.ish del(7)(q11.23q11.23)(ELN-)], VCFS/DiGeorge [46,XX,del(22)(q11.2q11.2)], or Klinefelter syndrome [47,XXY].
|
|
|
C19. You are asked to evaluate a 6-year-old boy with mild developmental delay and a distinctive dysmorphic facial appearance. In taking the history, you are told by his mother that his father has the exact same appearance. Which of the following syndromes are you most likely to remove from your differential diagnosis based on this clinical history?
A. Aarskog B. Noonan C. Robinow D. Pfeiffer E. Velocardiofacial |
Answer: A. While all the syndromes have a distinctive facial appearance, Aarskog syndrome is an X-linked disorder, so father-to-son transmission would not be seen. The other syndromes are autosomal dominant
|
|
|
C20. A man with a right-sided triphalangeal thumb and left sided absent thumb has a child with bilateral absence of the radius and an atrioventriculoseptal defect. Which of the following genetic concepts accounts for this clinical history?
A. Genetic heterogeneity B. Multifactorial inheritance C. Phenotypic pleiotropy D. Variable expression with complete penetrance E. Variable penetrance with incomplete expressivity |
Answer: D. The description fits Holt-Oram syndrome, and represents variable expression with complete penetrance
|
|
|
C21. A newborn boy manifests macrosomia (birth weight 5.2 Kg), coarse facies, and post-axial polydactyly. Which of the following clinical findings are you most likely to encounter when caring for this child?
A. Cardiac conduction defects B. Delayed bone age C. Father to son transmission D. Late onset retinitis pigmentosa E. Uniparental disomy for chromosome 11p |
Answer: A. The child in this scenario has Simpson-Golabi-Behmel syndrome, an X-linked overgrowth syndrome caused by mutations in Glypican 3 on Xq26. There is no parent of origin effect, and male to male transmission is not seen. These children have a high rate of cardiac conduction defects, which may account for the observation of unexplained death. Bone age is advanced initially, then becomes normal. Retinitis pigmentosa is not a common long-term complication
|
|
|
C22. A four-year-old girl is found to have relative macrocephaly, a broad forehead, a large open anterior fontanelle, and Wormian bones on X-ray. Her parents were told that she suffered bilateral clavicular fractures at birth, and they have never healed. Her father has a broad forehead, wide set eyes, and a history of dental problems, including supernumerary and ectopic teeth. Which of the following clinical findings has been associated with the underlying disorder?
A. Cytogenetic testing is needed to confirm the diagnosis. B. Most affected individuals have an adult height under 5 feet. C. Retinal detachment is a long-term risk. D. There is a lifetime increase risk for fractures. E. There is an increase rate of Caesarian section for affected women |
Answer: E. This scenario describes a child with Cleidocranial dysplasia (CCD). Women with CCD have an increased rate of needing a Caesarian section in childbirth. They do not have an increased fracture rate. Mild short stature can be seen, but adult heights are usually at the low end of the normal range. Retinal detachment is not a manifestation. Cytogenetic testing is not helpful. Some children have a microdeletion on 6p21, but it is not cytogenetically visible. These children usually have developmental delay/mental retardation in addition to the usual CCDS findings.
|
|
|
C23. A 3-year-old girl has hypodontia, alopecia, and mild developmental delay. Examination reveals hyperpigmented hyperkeratotic streaks. Her sister has severe developmental delay with seizures. Her mother has partial adontia and atrophic scalp hair. Which of the following clinical findings is most commonly associated with this disorder?
A. Affected females can only have unaffected males or affected females. B. Chromosome analysis of fibroblasts reveal an abnormality in 90% of cases. C. Germline mosaicism is a common etiology. D. One sees fewer than expected males in affected families. E. 67% of cases represent new mutations |
Answer: D. The condition describes is Incontinentia Pigmenti (IP), an X-linked male lethal trait. In such conditions one sees fewer than expected males in a given pedigree, as 1⁄2 of male fetuses (those affected) are lost. Germline mosaicism is not common in IP. For an X-linked lethal trait, approximately 1/3rd of cases are new mutations. There is no cytogenetic abnormality associated with IP. Chromosome analysis of fibroblasts demonstrates an abnormality in approximately 40% of cases of Hypomelanosis of Ito, a related but clinically distinct disorder. Affected females can have unaffected males and affected and unaffected females
|
|
|
C24. A 3-year-old boy manifests short stature, “Hitchhiker” thumbs, and “cauliflower” ears. What is the recurrence risk for his unaffected parents of having a subsequent child with the same condition?
A. <1% B. 5-7% C. 12.5% D. 25% E. 50% |
Answer: D. This child’s description is classic for Diastrophic Dysplasia, which is an autosomal recessive trait caused by mutations in the DDST gene
|
|
|
C25. Which of the following genes is most likely to be mutated in an individual with a hypercoagulable state? A. Factor VIII B. Factor IX C. Prothrombin D. Thrombin E. von Willebrand factor
|
C. The prothrombin G20210A mutation is associated with the hypercoagulable state. Mutation of any of the other listed proteins would lead to bleeding tendency, not increased tendency to form blood clots.
|
|
|
C26. Which of the following symptoms is the most common presenting complaint in individuals with hemochromatosis?
A. joint pain B. fatigue C. change in skin pigmentation D. nausea and vomiting E. decreased libido |
B
|
|
|
C27. Hereditary angioedema is due to deficiency in which of the following systems?
A. Antibodies B. B-cells C. Complement D. Macrophages E. T-cells |
C. Hereditary angioedema is due to C1q inhibitor deficiency in the complement system
|
|
|
C28. Which of the following is responsible for a phase I reaction in drug metabolism?
A. ABC transporter B. Acetylase C. Glucuronyl transferase D. P450 enzyme E. Transcarbamylase |
D
|
|
|
C29. The thiopurine methyltransferase polymorphism is important in treatment of which of the following disorders? * A. Hypertension B. Asthma C. Tuberculosis D. Leukemia E. Diabetes
|
Answer: D. The TPMT polymorphism affects metabolism of drugs such as 6-mercaptopurine, 6- thioguanine, etc., which have a role in treatment of leukemia and autoimmune disorders.
|
|
|
C30. Imatinib is used in the treatment of which of the following disorders?
A. Asthma B. Chronic myelogenous leukemia C. Coronary artery disease D. Diabetes E. Hypertension |
Answer: B. Imatinib targets the BCR-ABL kinase that results from the Philadelphia chromosome, which is associated with chronic myelogenous leukemia.
|
|
|
C31. A sodium channel polymorphism can be associated with which of the following side effects of medication?
A. Allergy B. Arrhythmia C. Hair loss D. Hepatitis E. Seizure |
Answer: B. The sodium channel polymorphism can lead to arrhythmia upon exposure to specific drugs
|
|
|
C32. You are asked to evaluate a well infant girl with apparently isolated Pierre Robin sequence. Which of the following diagnostic tests is most likely to yield a useful clinical finding?
A. Chromosome analysis B. Electrocardiogram (ECG) C. Eye exam D. FISH for del22q11.2 E. Skeletal survey |
Answer: C. In approximately 50% of cases, Pierre Robin sequence (PRS) is part of a genetic syndrome, and half of that is Stickler syndrome (SS). The majority of those with SS have eye involvement (only those cases caused by COL11A2 mutations do not). The eye findings of SS are usually evident in the newborn period. Chromosome abnormalities are unlikely in an otherwise normal baby with PRS. Del22q11.2 is the next most common syndromic cause of PRS, so it should be ordered in every baby with PRS. However, del22q11.2 is only about half as common as SS as the cause of PRS. Cardiac conduction abnormalities are unlikely in this setting.
|
|
|
C33. Chromosome analysis would be most helpful in diagnosis of which of the following syndromes?
A. Marfan syndrome B. Neurofibromatosis 1 C. Smith-Magenis syndrome D. Pfeiffer syndrome E. Williams syndrome |
Answer: C. SMS is caused by deletions of 17p11.2 visible with routine chromosome analysis (>550 bands), although deletions may be missed on first inspection. There is evidence that the majority of the manifestations may be attributable to haploinsufficiency of the RAI1 gene. While a small percentage of Neurofibromatosis 1 (NF1) is caused by deletions of the NF1 gene, the majority of cases are caused by point mutations in the NF1 gene. Furthermore, a cytogenetically visible deletion is very rare. Williams syndrome is caused by submicroscopic deletions of 7q11.2, encompassing the elastin gene and others as well. The Pfeiffer syndrome (PS) phenotype can be caused by a variety of different point mutations in FGFR1 (mild type 1 PS), FGFR2 (more severe type 1 as well as types 2 and 3 PS), and FGFR3 (some cases of FGFR3-related craniosynostosis, or Muenke syndrome, can look like PS). Marfan syndrome is generally caused by point mutations in fibrillin-1 on chromosome 15q21.
|
|
|
C34. Which of the following would be most useful in differentiating non-accidental injury (NAI) from osteogenesis imperfecta in a 5-month-old girl with unexplained fractures?
A. Blue sclerae B. Healing fractures of different ages C. Low socioeconomic status of the parents D. Retinal hemorrhages E. Type I collagen analysis |
Answer: D. Blue sclerae are seen in OI types 1, 2 and 3, but are also seen in most healthy babies as a normal variant. Healing fractures of different ages can be seen in OI as well as NAI. Type I collagen analysis is considered the ‘gold standard’ for the diagnosis of OI, but it can be normal in over 10% of OI, so a negative analysis does not rule out OI. NAI can be seen in families of any level of socioeconomic status of the parents. Retinal hemorrhages are not a feature of OI, but do suggest a diagnosis of NAI.
|
|
|
C35. A 3 year old girl has severe developmental delay, microcephaly, no speech, grand mal seizures, and ataxic limb movements. Chromosome analysis and FISH testing for a 15q11 deletion are normal. Which of the following genetic tests would be most appropriate to order in trying to determine the underlying etiology?
A. Cholesterol/7-delhydrocholesterol ratio B. FMR1 analysis C. MECP2 sequence analysis D. Methylation studies of chromosome 11p15 E. Uniparental disomy for chromosome 7 |
Answer: C. Mutations in MECP2 cause Rett syndrome, but also can cause an Angelman syndrome-like phenotype, as described above. Uniparental disomy (UPD) 7 causes idiopathic short stature and a small percentage of cases of Russell-Silver syndrome. FMR1 is the gene for Fragile X syndrome, and does not typically present with these findings. The ratio of cholesterol/7- dehydrocholesterol is used to diagnose Smith-Lemli-Opitz syndrome.
|
|
|
C36. Assuming complete penetrance for a point mutation, this pedigree (two paternal half sisters have 1 affected child each, one male one female) is most consistent with
A. autosomal dominant inheritance of a gene imprinted (not expressed) for the maternal allele B. autosomal dominant inheritance of a gene imprinted (not expressed) for the paternal allele C. mitochondrial inheritance D. X-linked dominant inheritance E. X-linked recessive inheritance |
Answer: B. The disorder was not expressed in the mother of the two affected children, since these women inherited the gene from their father. Their sons each inherited the mutation from a female, though, and therefore are affected.
|
|
|
C37. Which of the following is associated with increased sensitivity to treatment of small cell lung cancers with gefitinb?
A. BCR-ABL translocation B. EGF receptor mutation C. N-myc amplification D. RAS mutation E. RET mutation |
Answer: B. EGF receptor mutations are found in small cell lung cancers that are likely to respond to gefitinib.
|
|
|
C38. Which of the following hematologic disorders is commonly associated with a gene inversion?
A. Hemophilia A B. Hemophilia B C. Protein S deficiency D. Thalassemia E. Von Willebrand disease |
Answer: A. Hemophilia A is commonly associated with an inversion of the factor VIII gene
|
|
|
C39. Which of the following immune deficiency disorders is associated with thrombocytopenia?
A. Adenosine deaminase deficiency B. Ataxia-telangiectasia C. Severe combined immune deficiency D. Velocardiofacial syndrome E. Wiscott-Aldrich syndrome |
E
|
|
|
C40. Which of the following mutations is the most common mutation associated with hemochromatosis?
A. C282Y B. H63D C. I105T D. Q283P E. R330M |
A
|
|
|
C41 – C43: For each consultand described below, choose the chance that the consultand might have a child with a neural tube defect (in the US) from the percentages listed in A-E. You may choose an answer once, more than once, or not at all.
Percentages A. < 0.1% B. 0.1% to 1.9% C. 2% to 4% D. 5% to 10% E. >10% C41. A man with asymptomatic L-5 spina bifida occulta discovered on X-ray following a car accident C42. A woman whose maternal aunt's daughter had a baby with anencephaly C43. A normal couple whose first two children have isolated spina bifida |
C41: B, C42: B, C43: D
|
|
|
C44 – C46: For each situation described below, choose the coping response that best describes the consultands behavior, from those listed in A-E. You may choose an answer once, more than once, or not at all.
A. Anger B. Denial C. Intellectualization D. Projection E. Reaction formation C44. A father who is preoccupied with learning all about the embryology of his newborn son's cleft lip C45. A mother who insists that her 4 year old daughter with spina bifida is not walking because of her many hospitalizations C46. A mother who ascribes her son's fetal alcohol syndrome to her obstetrician's negligence |
C44: C, C45: B, C46: D
|
|
|
C47. Which of the following proteins represents the defective protein responsible for familial hypercholesterolemia?
A. ApoB-100 B. ApoE C. ApoB-48 D. Lipoprotein lipase E. LDL receptor |
E
|
|
|
C48. Which of the following skeletal disorders has been associated with defective Wnt signaling? * A. Osteogenesis imperfecta B. Osteopetrosis C. Pseudohypoparathyroidism D. Achondroplasia E. Osteoporosis
|
Answer: E. A mutation in LDL receptor protein (LRP6) has been found in a family with a number of conditions, including osteoporosis, and an LRP5 mutation in association with pseudogloma osteoporosis syndrome. Both are involved in the Wnt signaling pathway
|
