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)