Chapter 5: Genetic Disorders Flashcards
To examine chromosomes, the dividing cells are arrested in what phase of cell division?
a. anaphase
b. telophase
c. metaphase
d. prophase
C
The chromosomal segment located on the long arm of the X chromosome in region 1, band 3, and sub-band 2 is written in which notation?
a. Xp13.2
b. Xp1.32
c. Xq1.32
d. Xq13.2
D
What is the usual cause of aneuploidy (occurs if an error occurs in meiosis or mitosis and a cell acquired a chromosome complement that is not exact multiple of 23)?
a. nondisjunction
b. anaphase lag
c. metaphase lag
d. both a and b
e. both a and c
D
Euploid: exact multiple of haploid number of chromosomes (23)
What is the structural abnormality wherein the break occurs at both ends with fusion of damaged ends?
a. deletion
b. ring chromosome
c. inversion
d. translocation
B
deletion - loss of a portion of a chromosome
inversion - rearrangement that involves 2 breaks within a single chromosome with reincorporation of inverted, intervening segment
translocation - segment of 1 chromosome transferred to another
There are single breaks in each of two chromosomes, with exchange of material
a. Roberstsonian translocation
b. Centric fusion
c. Isochromosome
d. Balanced reciprocal translocation
D
Robertsonian - translocation between two acrocentric chromosomes (centric fusion)
isochromosome - results when one arm of a chromosome is lost and the remaining arm is duplicated (two short or two long arms only)
Which is not a clinical feature of Trisomy 21 or Down Syndrome?
a. flat facial profile
b. epicanthic folds
c. oblique palpebral features
d. none of the options
D
Which of the following is an example of chromosome 22q11.2 deletion syndrome
a. velocardiofacial syndrome
b. klinefelter syndrome
c. turner syndrome
d. hermaphroditism
A
and DiGeorge syndrome
Which of the following is true about Lyon hypothesis?
a. Only one of the X chromosomes in genetically inactive
b. Activation of either the maternal or the paternal X chromosome occurs at random among blastocysts
c. The other X chromosome of either maternal or paternal origin undergoes heteropyknosis
d. Activation of the same X chromosome persists in all the cells derived from each precursor cell
C
Which of the following is not an example of cytogenetic disorder involving sex chromosomes?
a. Hermaphroditism
b. Pseudohermaphroditism
c. Turner syndrome
d. Klinefelter Syndrome
e. none of the options
E
Which is not true about male hypogonadism?
a. 2 or more X chromosomes
b. 1 or more Y chromosomes
c. mitotic nondisjunction
d. aneuploidy
C
meiotic
Which is not a type of karyotypic abnormality in Turner syndrome?
a. mosaic type
b. complete monosomy of the X chromosome
c. missing an entire X chromosome
d. defective second X chromosome
B
should be partial
Which is not true about single-gene disorder with nonclassic inheritance?
a. disorders associated with phenotypic mosaicism
b. diseases caused by trinucleotide repeat mutations
c. diseases caused by mutations in mitochondrial gene
d. disorders associated with genomic imprinting
A
should be gonadal mosaicism
What is the most distinctive feature of Fragile X Syndrome (FXS)?
a. hyperextensible joints
b. macro-orchidism
c. high arched palate
d. large testicles
B
It is also referred to as “happy puppets”
a. Prader Willi syndrome
b. Angelman syndrome
c. Fragile X syndrome
d. Huntington disease
B
Which of the following is not a molecular basis of Angelman and Prader Willi Syndrome?
a. deletions
b. uniparental disomy
c. complete monosomy
d. defective imprinting
C
uniparental disomy - have two maternal copies of chromosome 15
