Lecture 17 - QF PCR Flashcards
What is aneuploidy
the gain or loss of a chromosome
What is monosomy
the loss of a chromosome
What is disomy
two copies of a chromosome
What is trisomy
three copies of a chromosome
What is non-disjunction
the failure of one or more pairs of homologous chromosomes to separate normally during nuclear division resulting in an abnormal distribution of chromosomes
What is turner syndrome
- 45 , X
- caused by paternal non-disjunction
What is the frequency of turner syndrome
1 in 2500 newborn girls
What is the phenotype of turner syndrome
-short stature
-webbed neck
-low hairline
-loss of ovarian function
-cardiac defects
-kidney disease
-normal intelligence
What is klinefelter syndrome
- 47, XXY
- caused by paternal and maternal non-disjunction
What is the phenotype of klinefelter syndrome
- tall with long limbs
- small testes and penis
- breast growth
- decrease sexual interest
- lower than average intellignece
what is the frequency of klinefelter syndrome
1/650 newborn boys in the US
1-2/1000 live male births in the UK
What is trisomy X
- 47, XXX
- caused by maternal non-disjunction
What is the phenotype of trisomy X
- taller than average
- developmental delays
What is the frequency of trisomy X
1/1000 female births in canada and the us
What is Jacob syndrome
- 47, XYY
- caused by paternal non-disjunction or post-zygotic cleavage errors
What is the phenotype of Jacob syndrome
- tall
- enlarged head
- anti-social
- learning disabiliities
- usually fertile
What is the frequency of jacob syndrome
1 in 1000 live male births
What is patau syndrome
- 47, XX+13 or 47, XY+13
- caused by non-disjunction of either parent
What is the phenotype of patau syndrome
- small eyes
- extra digits
- cleft palate
- heart and CNS defects
What is the frequency of patau syndrome
1/16 000 newborns
~90% of infants die within a year
What is edwards syndrome
- 47, XX+18 or 47, XY+18
- caused by maternal non-disjunction
What is the phenotype of edwards syndrome
- small, long head
- small mouth
- underweight
- feeding and breathing problems
- heart and genitorinary issues
- severe cognitive impairment
What is the frequency of edwards syndrome
1/5000 newborns
~90% of infants die within a year
What is downs syndrome
- 47, XX+21 or 47, XY+21
- caused by maternal non-disjunction
What is the phenotype of downs syndrome
- craniofacial abnormalities
- early-onset alzheimers
- mild to moderate cognitive impairment
What is the frequency of downs syndrome
1/700 newborns
What are short tandem repeats
short nucleotide sequences that repeat multiple times
How can we determine STR
amplification via PCR that produces products of variable sizes
How is monosomy seen in STR
one PCR product
How is disomy seen in STR
two PCR products
How is trisomy seen in STR
three PCR products
