Numerical and Structural Chromosome Abnormalities
Very few trisomy 18 children live beyond what year of age?
1
What chromosomes are acrocentric?
13, 14, 15, 21, and 22
90-95% of all Down Syndrome patients have what karyotype?
47+21
What percent of all miscarriages are due to chromosomal abnormalities?
50
Balanced translocation carriers have an increased risk of what?
Abnormal Chromsomal Offspring
What cancer are those with Down syndrome at an increased risk for?
Acute lymphoblastic leukemia
Klinefelter syndrome may not be diagnosed till when?
Adulthood
Any abnormal number of chromosome that is not a multiple of n is called what?
Aneuploidy
If there is no loss or gain of significant chromosomal material then the individual is mentally and physically normal, this is referred to as what?
Balanced Translocation
What kind of problems may parents of children with Klinefelter's Syndrome have?
Behavioral problems
What types of cells are used in routine cytogenetic analysis?
Blood Skin Solid tumors Bone marrow Miscarriage Amniotic fluid CVS
Why can't someone with trisomy 18 open their hand?
Bones fused together
Klinefelter syndrome individuals have a higher risk of what cancer.
Breast
What is a disadvantage of FISH?
Can't label every chromosome, have to be very specific
What is frequently found in people with cancer, developmental delay, dysmorphic features, multiple malformations, short stature, ambiguous genitalia, and intellectual disability?
Chromosome abnormalities
80% those with Patau Syndrome have what two defects?
Cleft lip/palate Congenital heart defects
What are common clinical features of trisomy 18?
Clenched hand, often deformed fingers and toes Rocker bottom feet Low-set malformed ears Short sternum Congenital heart defects
What test isolates DNA and reference DNA and let's them compete for hybridization to detect extra material?
Comparative Genomic Hybridization
What is a variation of FISH used in the detection of chromosomal cancer changes?
Comparative Genomic Hybridization (CGH)
The study of chromosomes and their structure, inheritance, and abnormalities is...
Cytogenetics
What kind of cells (dead or live) can you use in FISH?
Dead
What refers to the loss of a segment of a chromosome?
Deletion
Cri du Chat syndrome is caused because what happens to the chromosome?
Deletion on 5p
Why is important to test parents of an unbalanced translocation child?
Determine risk for future pregnancies Determine region of translocation-trisomic or monosomic
When discussing chromosomal changes in cancer, what appear as very small, usually paired dots with no centromere, irregular segregation and variable numbers?
Double minutes
What test combines basic principles of molecular biology and cytogenetics?
FISH
In Edwards syndrome, 80% are what sex?
Female
What is the most common cause of triploidy?
Fertilization of one egg by two sperm
FISH stands for what?
Fluorescence in situ Hybridization
Routine cytogenetic analysis can be done on almost any cell type that is..
Fresh live
Small ear canals in those with Down Syndrome cause what?
Hearing deficits
In the most severe cases of trisomy 13 the forebrain fails to separate into two hemispheres this is referred to as what?
Holoprocencephaly
When discussing chromosomal changes in cancer, what material is duplicated millions of times and inserted into a chromosome?
Homogeneously Staining Regions (HSR)
Males with Klinefelter syndrome usually have what genitourinary problem?
Infertility, small penis and testes
People with Turner syndrome have normal...
Intelligence
What organization is for gene mapping?
International System for Human Cytogenetic Nomenclature
When chromosomes are classified into a specific pattern this is referred to as...
Karyotyping
47XXY is what syndrome?
Klinefelter Syndrome
The cry in cri du chat is caused by abnormal development of what?
Larynx
What leads to the web-neck of someone with Turner Syndrome?
Lymphedema
The risk of having a child with Down Syndrome increases with...
Maternal age
What stage of mitosis allows for the best visualization of chromosomes?
Metaphase
What is the outcome usually of a trisomy 13 baby?
Miscarriage/Only live a few days
Nondisjunction in mitosis after fertilization leads to what?
Mosaicism
Do cells have to be in metaphase to perform FISH?
No can be in interphase
Aneuploidy results from what?
Nondisjunction
What is the failure of the chromosomes or chromatids to properly divide during meiosis I or II resulting in sperm or egg with 22 or 24 chromosomes?
Nondisjunction
The most common trisomy is Down syndrome because..
Other trisomies are lethal
90% of females with Turner Syndrome are missing or have abnormal what?
Ovaries
The short arm of the chromosomes is the...
P arm
It is important to test who when a unbalanced translocation is found?
Parents
Trisomy 13 is also known as what syndrome?
Patau Syndrome
What may someone with trisomy 13 have on their extremities?
Polydactyl
Any multiple of the haploid chromosome number is called what?
Polyploid
Almost 100% of _______________ (aneuploidy or polyploidy) are miscarried
Polyploidy
The long arm of the chromosome is the...
Q arm
What is an exchange of material between two chromosomes?
Reciprocal Translocation
3-4% of all Down Syndrome Patients have what translocation?
Robertsonian
What is a translocation between any two acrocentric chromosomes?
Robertsonian Translocations
What kind of crease may be present on the hand of someone with Down syndrome?
Simian crease
Everybody born with cleft lip/palate is tested for what?
Trisomy 13
45X is what syndrome?
Turner syndrome
1% of all Down Syndrome patients have what translocation?
homologous 21;21 translocation
What translocation has 100% chance of haven an abnormal child?
t(21q;21q)
