What are the different kinds of chromosomal abnormalities?
When does first trimester begin and end?
First day of someone's last period and lasts until the end of week 12 of an embryo's life
What percentage of miscarriages during the first trimester are due to chromosomal abnormalities?
What are the kinds of numerical abnormalities?
Trisomy (additional chromosomes)
Monosomy (less chromosomes)
What is trisomy?
What is monosomy?
What are examples of trisomy?
Patau syndrome (additional 13)
Edwards syndrome (additional 18)
Downs syndrome (additional 21)
Klinefelter (boys have additional X)
Patau syndrome is an additional what chromosome?
Edwards syndrome is an additional what chromosome?
Downs syndrome is an additional what chromosome?
Klinefelter syndrome is an additional what chromosome?
Boys have an additional X chromosome
What is an example of a monosomy?
Turner's syndrome (female missing all or part of X chromosome)
What chromosome is missing in turner's syndrome?
Female missing all or part of X chromosome
What is disomy?
The condition of having a chromosome represented twice in a chromosomal complaint
What is aneuploudy?
The presence of an abnormal amount of chromosomes in a cell
What is nondisjunction?
Failure of chromosomes to seperate properly during cell division
What may the origin of nondysjunction be?
Paternal or maternal, with different kinds of trisomys having different likeliness of each
Most autosomal are maternal and sex monosomy sex linked is paternal and trisomy sex linked is even
What are examples of autosomal chromosomes aneuploidy syndromes?
Down syndrome (trisomy 21)
Patau syndrome (trisomy 13)
Edwards syndrome (trisomy 18)
What are the chances of inheriting trisomy 21 (down syndrome)?
What causes the chances of inheriting down syndrome to increase?
Increases with maternal age
What are some characteristics of down syndrome?
Facial dysmorphologies (birth defects that affect anatomy)
IQ less than 50
Alzheimer's disease in later life
What is down syndrome normally due to?
Non-dysjunction of chromosome 21 which is usually maternal (95%)
What is the occurance of trisomy 13 (patau syndrome)?
What are some characteristics of patau syndrome?
Multiple dysmorphic features and mental retardnation
Very few survive beyond first year
What is patau syndrome normally caused by?
Nondysjunction of chromosome 13 (90%)
What is the occurance of trisomy 18 (edwards syndrome)?
What are some characteristics of edwards syndrome?
Severe developmental problems
Most die in first year
What is edwards syndrome normally caused by?
What are some sex chromosomes aneuploidy syndromes?
Turner's syndrome (45, X)
Klinefelter syndrome (47, XXY)
What is the occurance of turner's syndrome?