(F) Cytogenetic Disorders (transes-based) Flashcards
an abnormal chromosomal number or
alterations in structure of one or more
chromosomes results to?
disease
Definition of terms
Complete sets of chromosome with none
extra or missing
Euploidy
TOF. The normal human cells are haploid,
having two sets of 23 chromosomes
F (diploid)
one or more individual chromosomes are extra or missing from a euploid set
aneuploidy
Aneuploidy
Pair 6 chromosomes is an example of?
Nullisomy
Aneuploidy
Missing pair of homologs
Nullisomy
Aneuploidy
This occurs at preimplantation and can be lethal.
Nullisomy
Aneuploidy
One chromosome is missing
Monosomy
Aneuploidy
Occurs at embryonic stage and may be lethal.
Monosomy
TOF. Turner’s syndrome is an example of trisomy.
F (monosomy)
TOF. Triploidy has 3 set of chromosomes while trisomy only has two sets with one chromosome that has an extra copy.
T
Aneuploidy
Three copies of a particular
chromosome in an otherwise diploid cel
Trisomy
Aneuploidy
TOF. 47, XX or X,Y +21 is an example of triploidy.
F (trisomy)
TOF. Trisomy, similarly to monosomy, occurs at embryonic stage and may be lethal.
T
Trisomy 21 AKA
Down Syndrome
TOF. The incidence of livebirths with people with down syndrome are 1:7000 live births
F (1:700)
causes of down syndrome?
nondysjunction, translocation and mosaics
TOF. Trisomy 21 and Trisomy 13 have the same causes.
T
TOF. Trisomy 13 and Trisomy 18 have the same causes.
F (walang translocation sa trisomy 18)
TOF. in trisomy 21, mosaicism is the most common cause.
F [nondisjunction 92.5-95% while Mosaicism (< 3%)]
TOF. The translocation as a cause of down syndrome is only 5%.
T
Specific Autosomal Aneu.
47,XX or XY + 21
Trisomy 21: Nondisjunction
Specific Autosomal Aneu.
46,XX or XY , der(14,21) (q10;q10) + 21
Trisomy 21: Translocation
Specific Autosomal Aneu.
○ 47,XX + 21/46,XX
○ 47,XY + 21/46,XY
Trisomy 21: Mosaicism
Life expectancy of Nondisjunction: Down Syndrome
2nd and 3rd decade of life
Trisomy 21
Life expectancy of Translocation
2nd and 3rd decade of life
Trisomy 21
Life expectancy of Mosaicism
n/a
Trisomy 18
aka?
EDWARD SYNDROME
TRISOMY 13
TOF. 1 in 4,000 to 15,000 live births
T
Specific Autosomal Aneu.
47,XX or XY +13
Trisomy 13: Nondis
Specific Autosomal Aneu.
46,XX or XY , der(13,14) (q10;q10) + 13
Trisomy 13: Trans
Specific Autosomal Aneu.
○ 46,XX/47,XX + 13
○ 46,XY/47,XY + 13
Trisomy 13: Mosa
Life expectancy of trisomy 18 and 13 if the cause is translocation?
A. <1 month
B. < 1 week
C. AOTA
D. NOTA
D
walang trans sa trisomy 18
Life expectancy of trisomy 18 and 13 if the cause is nondisjunction?
A. <1 month
B. < 1 week
C. AOTA
D. NOTA
C (A & B kasi within 1st month)
Trisomy 18
Live births of Trisomy 18
A. 1 in 4000
B. 1 in 8000
C. 1 in 1500
D. 2 in 8000
B
Trisomy 18
Mosaicism
A. 46,XX/47,XX +18
B. 46,XX/47,XX + 13
C. AOTA
D. NOTA
A
○ 46,XX/47,XX +18
○ 46,XY/47,XY +18
Trisomy 18
Identify Cause: 47,XX or XY +18
Nondisjunction
Risk association of autosomal aneuploidies
Increased maternal age
TOF. A child with translocation indicates translocation in one of the parents thus karyotyping of mother is needed, to know if there is an increased probability of having another child with Down syndrome due to the risk of maternal age.
F (both parents is needed)
At what age is considered to have a high-risk pregnancy?
35
Identify disease
Trisomy 21: down syndrome
a bands of 21 q22.12-21q22.3 is a common indicator for?
down syndrome
Most common of the chromosomal disorders
Trisomy 21
FEATURES OF AN INDIVIDUAL WITH DOWN SYNDROME, except:
A. Abundant Neck Skin
B. Low Set Ears
C. Simian Crease
D. Umbilical Hernia
E. Hypotonia
B (should be small ears, low ears is for trisomy 18)
Trisomy 21
Which is not true
A. Protruding Tongue
B. Decreased functional activity of the gonads
C. Heart defects occur 50%
D. Obstruction through the
flow of the chyme
C(40%)