Alexandria University Semester: Autumn Medical Research Institute Academic year: 2019/2020 Department of Human Genetics Time allowed: 120 minutes Master Degree Date: 6/01/2020 Course title: Clinical Cytogenetics Total marks: 60 marks Course code: 1713708 Final Exam ______Question 1: (30 marks, 30 mins) Choose the correct answer:(0.5-mark, 1 min each) 1- A child is born with a cleft lip and palate. This birth defect may be associated with the following: a) A disruption defect related to amniotic bands. b) A healthy, otherwise completely normal, newborn infant. c) A chromosome disorder such as 13. d) All of the above. 2-The most common in first trimester spontaneous miscarriages is: a) trisomy. b) . c) triploidy. d) . 3- Which of the following is not compatible with survival to birth? a) 47,XY,+13 b) 47,XX,+18 c) 47,XY,+21 d) 45,Y 4- The DiGeorge syndrome is caused by a in which chromosome? a) 4 b) 7 c) 15 d) 22 5- Which of the following is not a chromosome instability syndrome? a) b) Ataxia telangiectasia c) Fanconi anaemia d) Bloom syndrome

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6- Which of the following trisomy karyotypes has the mildest effect on human development? a) 47,XXX b) 47,XXY c) 47,XX,+13 d) 47,XY,+21 7- Triploids have _____ of each kind of chromosome. a) one b) two c) three d) four 8- When an individual has only one of a particular type of chromosome it's described as _____. a) monosomy b) disomy c) trisomy d) tetrasomy 9- A(n) _____ is the movement of a segment of a chromosome from one chromosome to another nonhomologous chromosome. a) inversion b) translocation c) deletion d) duplication 10- When a broken segment from one chromosome attaches to its homologue a(n) _____ occurs. a) duplication b) deletion c) inversion d) both A and B 11- Which of the following may result in abnormal and offspring? a) inversion b) translocation c) deletion d) all of the above

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12- that tends to run in the family of either the mother or father is the result of _____. a) deletion b) inversion c) duplication d) translocation 13- is the result of a(n) _____. a) inversion b) translocation c) deletion d) duplication 14- Which of the following cell types is not used to examine chromosomes? a) white blood cells b) bone marrow cells c) red blood cells d) all of the above can be used 15- Chromosomes may be broken by _____. a) viruses b) radiation c) certain organic chemicals d) all of the above 16- A(n) _____ occurs when a segment of chromosome is turned around 180o. a) inversion b) translocation c) deletion d) duplication 17- When a is done chromosomes are arranged in pairs based on _____. a) size b) shape c) centromere location d) all of the above 18- _____. a) results in gametes with too few chromosomes b) can occur during I c) can occur during meiosis II d) all of the above

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19- Cri-du-chat syndrome is associated with a) a missing chromosome number 5. b) an additional chromosome number 5. c) a deletion of the long arm of chromosome number 5. d) a deletion of the short arm of chromosome number 5. 20- Approximately ____ percentage of spontaneous abortions result from extra or missing chromosomes. a) 10 b) 25 c) 50 d) 75 21- The most common autosomal aneuploid is a) trisomy 13. b) trisomy 15. c) trisomy 18. d) trisomy 21. 22- A (an)____ chromosome has its centromere near a tip so that it has one long arm and one very short arm. a) metacentric b) submetacentric c) acrocentric d) none of the above 23- In a (an)____, the short arm of two acrocentric chromosomes break, and the long arms join, forming an unusual, long chromosome. a) Robertsonian translocation b) reciprocal translocation c) inversion d) duplication 24- When chromatids divide along the wrong plane, structures with identical arms called ____ are formed. a) ring chromosomes b) translocations c) isochromosomes d) satellites 25- ____ contains protein-encoding genes. a) heterochromatin b) euchromatin c) pericentric inversions d) aneuploids

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26- Heterochromatic regions at the ends of chromosomes are called a) centromeres. b) euchromatin. c) telomeres. d) satellites. 27- A triploid human karyotype has how many chromosomes? a) 23. b) 46. c) 69. d) 92. 28- Nondisjunction of during meiosis II in human females can result in all of the following chromosome complements in a zygote except (assume the oocyte is fertilized by a sperm with a normal chromosome set) a) no chromosome 21. b) euploid for chromosome 21. c) monosomic for chromosome 21. d) trisomic for chromosome 21. 29- Consider the following normal sequence of genes: a b c d e f g h. The sequence a b f e d c g h represents a (an) a) deletion. b) duplication. c) inversion. d) translocation. 30- Which of the following karyotypes is not possible in the offspring of a translocation carrier (involving chromosomes 14 and 21) and a normal individual. a) deficient 14 or deficient 21 b) normal c) translocation Down syndrome d) all are possible outcomes 31-The sequential development of the genital system can best be described as : a) internal and external genital tract dependent upon primordial secretion b) gonadal differentiation and hormone secretion determining internal then external tract development c) hormone secretion forming genital ridge then internal and external tract development d) internal tract determining gonadal then hormone secretion for external tract development

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e) forming genital ridge then hormone secretion for internal and external tract development 32-The offspring of a 45,X female : a) Normal females b) Normal males c) Offspring with a chromosome anomaly d) None of the above 33- The offspring of a 47,XXY will be a) Males only b) Females only c) Half males and half females d) Non of the above 34- deletion occur in: a) Monosomy of b) Partial monosomy of a sex chromosome c) Monosomy of sex chromosome d) Partial monosomy of an autosome 35-Which of the following would result in a Turner a- Mos 47,XXX[15]/46,XX[35] b- 46,X,r(X) c- 45,XX,rob(21;22)(q10;q10) d- 46,XX,t(X;1)(q22;p21) 36-A chromosomal analysis is obtained on a young woman with mild signs of and reveals a mos 45,X [30]/46,XX[20] karyotype. Nondisjunction is most likely to have occurred in: a) maternal meiosis I b) maternal meiosis II c) paternal meiosis I d) mitosis after fertilization

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37-The meiotic error leading to an XYY male is: a) Meiosis I in mother b) Meiosis I in father c) Meiosis II in mother d) Meiosis II in father 38. is usually deleterious as ______a) Chromosomal pairing is hampered b) Gene balance is disrupted c) Size of individual may vary d) Chromosomal disintegration is increased 39. Klinefelter syndrome results due to ______a) Non-disjunction in the male b) Non-disjunction in the female gamete c) Gradual loss of chromosome d) Non-disjunction in any of the gametes 40-. is a result of which of the following? a) Non-disjunction of sex chromosome in female b) Non- disjunction of sex chromosome in male c) Non-disjunction of d) Non-disjunction of 41-. At what maternal age the probability of having a child with Down’s syndrome is increased drastically? a) 25 b) 30 c) 35 d) 45 42. Chromosome ______trisomy leads to Edward’s syndrome. a) 12 b) 13 c) 18 d) 21 43. Which one of the following is the only active gene in the inactivated ? a) XIST b) XCE c) Histone coding gene d) Ribosomal gene 44. A Y linked gene ______a) Is expressed only when homozygous b) Is present near the telomere of long arm in human

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c) Is carried by mother d) Expressed only in men 45. An X linked recessive gene would appear to ______a) Be expressed in both males and females equally b) Skip generations c) Be lethal d) Gradually degrade 46. Which of the following is wrong? a) lacks dosage compensation b) DMD gene is an X linked gene. c) Y linked gene like hemophilia passes from father to son d) X linked recessive genes are carried by females 47. A turner child born to normal parents is hemophilic. Where did the non- disjunction occur? a) Mother b) Father c) Zygote d) Grand mother 48. Deletion of a region led to over expression of a gene X. What do you conclude from this observation? a) Part of gene X is mutated b) Promoter of gene X is deleted c) Regulator of gene X is deleted d) No effect on gene X or its regulators 49. Which of the following is wrong for sex chromosome? a) X chromosome is larger than Y b) Female human are homozygous c) Y chromosome carries TDF d) All genes present on Y chromosome are unique to it 50- A child was born XY, but never developed external male genitals. The child has: a) 46,XY CGD b) Androgen-insensitivity syndrome c) ovotesticular DSD d) Down Syndrome 51-Chris was born XY and appeared female during childhood. Chris has: a) 46,XY CGD b) Androgen-insensitivity syndrome c) ovotesticular DSD d) Down Syndrome

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52-Sex determination occurs initially through the SRY transcription factor acting on : a) primordial germ cells b) c) testes support cells d) support cells e) mesonephric duct cells 53- Patients with Frasier syndrome show a) XY complete . b) XX complete gonadal dysgenesis. c) XY partial gonadal dysgenesis. d) XX partial gonadal dysgenesis. 54-Denys-Drash syndrome is caused by a) DAX1 b) WNT4 mutation c) WT1 mutation d) SF1 mutation 55- Which statement is true about NR5A1 gene mutation: a) leading to ambiguous genitalia, partial gonadal dysgenesis, and absent or rudimentary Wolffian structures b) leading to ambiguous genitalia, complete gonadal dysgenesis, and absent or rudimentary Wolffian structures c) leading to ambiguous genitalia, partial gonadal dysgenesis, and well developed müllerian structures d) leading to ambiguous genitalia, partial gonadal dysgenesis, and absent or rudimentary müllerian structures 56- Which statement is wrong about DAX1 gene: a) Is located at Xp21.3 b) encodes a transcription factor that plays a dosage-sensitive role in sex determination development c) Inhibit SRY and SOX9 d) Activate expression of AMH 57-From the causes of 46,XY female a) WNT4 duplication b) SRY translocation c) SOX9 duplication d) RSPO1 mutation 58-From the causes of 46,XX male a) WNT4 duplication b) WT1 mutation

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c) SOX9 deletion d) RSPO1 mutation 59- All those patients have tall stature except: a) 47,XXY b) 48,XXYY c) 48,XXXY d) 49,XXXXY 60-The most common genotype of ovotesticular DSD is: a) 46,XX b) 46,XX/46,XY c) 46,XY d) 46,XX/45,X

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Question no. 2: (30marks, 90 mins) Short question: 1- Write short note on Cri du chat syndrome (3marks)

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2- Write short note on Mendelian disorders with cytogenetic effects (4marks)

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3- Write short note on Parent of origin effect (3marks)

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4- Complete: (5marks)

A- Complete are generally not viable expect for …………. B- The most common isochromosome is …………. In some individuals with …………….

C-The most common inversion seen in human chromosomes is …………..

D-The deletion in chromosome 15q11-13 leads to ………….. syndrome if the father has the deletion and ………… syndrome if the mother has the deletion

F-……………is an autosomal dominant condition caused by deletion within 22q11, while duplication of the same part leads to ……….

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5-Write short note on SOX9 gene (3 marks)

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6- There are several forms of androgen insensitivity that result in 46,XY DSD. Discuss in brief. (4 marks) ------

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7-What are the most common causes of ambiguous genitalia? Discuss in short one cause. (4marks)

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8- A male child presented to our genetic clinic with delayed speech, clinical examination revealed small testes. Karyotype result was 47,XXY. The parents were worried about the diagnosis, could you give this family a proper genetic counselling? (4marks)

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