Chromosomal Aberrations Flashcards
Occur when there is a defect in a chromosome, or in the arrangement of the genetic material on the chromosome.
Chromosomal abnormalities
If there is an error in cell division, the egg or sperm can end up with too many or not enough chromosomes.
[etiology]
Meiosis
If the chromosome do not split into halves, the new cells can have an extra chromosome or have a missing chromosome.
[etiology]
Mitosis
Eggs are also aging and may have the incorrect number of chromosomes at the time of fertilization.
[etiology]
Maternal age
It describes a relationship between two people who share a common ancestor or shared a blood relationship.
[etiology]
Consanguinity
It is teratogenic.
[etiology]
Radiations
It may include medications, foods, etc.
[etiology]
Environment
[5] Numerical
- Monosomy
- Trisomy
- Tetrasomy
- Triploidy
- Tetraploidy
[6] Structural
- Deletion
- Translocation
- Insertion
- Isochromosome
- Ring chromosome
- Duplication
One chromosome is missing.
[numerical]
Monosomy
When a chromosome does not separate properly during Meiosis I or II it is called as?
[numerical]
Meiotic nondisjunction
It is incompatible with survival because of loss of too much genetic information.
[numerical]
Monosomy
3 instances of a particular chromosome are present instead of normal 2 chromosomes.
[numerical]
Trisomy
Occurs if the chromosomes fail to separate properly during cell division.
[numerical]
Trisomy
It is a deviation of an abnormal number of chromosomes in which an additional chromosome pair is added to a particular chromosome.
[numerical]
Tetrasomy
A cell contains 48 chromosomes.
[numerical]
Tetrasomy
There is a complete set of extra chromosome.
[numerical]
Triploidy
Two extra chromosome set are pre
[numerical]sent. So, a cell contains 92 chromosomes.
Tetraploidy
Not compatible with life.
[numerical]
Tetraploidy
It means of loss of small portion of chromosome.
[structural]
Deletion
Occurs from breakage at random in both chromatids of a chromosome or only in one chromatid.
[structural]
Deletion
Sometimes a segment of a chromosome becomes detached and unites with another non-homologous chromosome.
[structural]
Translocation
[2] types of Translocation
- Simple
- Reciprocal
A fragment is transferred from a chromosome to a non-homologous chromosome.
[structural]
Insertion
It is a rare non-reciprocal type of translocation which involves three breaks.
[structural]
Insertion
This results in having extra genetic material, even though usually normal.
[structural]
Duplication
May cause affected genes to not function properly.
[structural]
Duplication
These extra instructions can lead to errors in the development of a baby.
[structural]
Duplication
It results when there are two breaks in a chromosome and the detached segment becomes reinserted in the reverse order.
[structural]
Inversion
[2] types of Inversion
- Paracentric
- Pericentric
Both breaks in one arm of chromosome.
[inversion]
Paracentric
It has breakpoints on either side of the centromere.
[inversion]
Pericentric
It is a chromosome that has lost one of its arm and replaced it with an exact copy of the other arm.
[structural]
Isochromosome
It is a chromosome whose arms have fused together to form a ring.
[structural]
Ring chromosome
Happens due to the trisomy for chromosome 21.
[syndrome]
Down syndrome
The most common autosomal aneuploidy among live-borns.
[syndrome]
Down syndrome
This syndrome is also known as ‘Mongolism’ or ‘Mongolian idiocy’.
[syndrome]
Down syndrome
Persons with this syndrome shows a strong mental retardation.
[syndrome]
Down syndrome
Their body is short about 120cm with stubby fingers.
[syndrome]
Down syndrome
They also possess wide nostrils, swollen tongue, monkey-like skin ridges on extremities. The most queer feature is the epicanthic fold— the prominent eyelid folds like those of Mongolian people. The persons usually survive about sixteen years.
[syndrome]
Down syndrome
Prompted Sir John Langdon Haydon Down to term the condition to Mongoloid (1866).
[syndrome]
Epicanthal fold
Happens due to trisomic condition in chromosome no. 13.
[syndrome]
Patau syndrome
The persons suffering from this syndrome show harelip, cleft palate, and serious cerebral, ocular and cardiovascular defects.
[syndrome]
Patau syndrome
Average survival is about three months; a few live up to five years.
[syndrome]
Patau syndrome
In this syndrome there is an extra chromosome 13.
[syndrome]
Patau syndrome
Happens due to the trisomic condition for the chromosome no. 18.
[syndrome]
Edward syndrome
The syndrome is characterized by mental deficiency; multiple congenital malformations affect virtually every organ system.
[syndrome]
Edward synrome
Great physical and mental abilities (6-month level).
[syndrome]
Edward syndrome
Babies suffering from this syndrome usually die within a year. In some rare cases they survive up to their teen years.
[syndrome]
Edward syndrome
It is caused by the presence of three – as opposed to two – copies of chromosome 18 in a fetus’ or infant’s cells.
[syndrome]
Edward syndrome
Large toes (fused 2nd and 3rd) and “Rocker-Bottom” Feet.
[syndrome]
Edward syndrome
Male aneuploidy.
[syndrome]
Klinefelter’s syndrome
47, XXY Karyotype
[syndrome]
Klinefelter’s syndrome
Happens due to the trisomic condition for the sex chromosomes (XXY).
[syndrome]
Klinefelter’s syndrome
Individuals possessing this syndrome are phenotypically males but with some tendency toward femaleness, particularly in secondary sex characteristics.
[syndrome]
Klinefelter’s syndrome
The condition exists in roughly 1 out of every 650 males. One in every 500 males has an extra X chromosome but may not show symptoms. Other mammals also have the XXY syndrome, including mice.
[syndrome]
Klinefelter’s syndrome
Principal effects include hypogonadism and reduced fertility.
[syndrome]
Klinefelter’s syndrome
Female aneuploidy.
[syndrome]
Turner syndrome
Named after Henry Turner (1938).
[syndrome]
Turner syndrome
45, X Karyotype ; XO Syndrome.
[syndrome]
Turner syndrome
Happens due to monosomy for X chromosome i.e. the individuals possess one normal X, while the short arm of the other X is missing.
[syndrome]
Turner syndrome
Therefore adults with Turner Syndrome are females having virtually no ovaries.
[syndrome]
Turner syndrome
The secondary sex characters are also poorly developed. Besides, they show short stature, low set ears, webbed neck and a shield-like chest.
[syndrome]
Turner syndrome
But it is interesting that these individuals generally do not show any mental retardation.
[syndrome]
Turner syndrome
Turner syndrome aka?
[syndrome]
Ullrich-Turner Syndrome or “Gonadal dysgenesis”
Also known as “Gonadal dysgenesis”.
[syndrome]
Turner syndrome
Encompasses several conditions, of which monosomy X (absence of an entire sex chromosome, the Barr body) is most common. It is a chromosomal abnormality in which all or part of one of the sex chromosomes is absent (unaffected humans have 46 chromosomes, of which two are sex chromosomes).
[syndrome]
Turner syndrome
Also a Female aneuploidy like turner syndrome.
Triple X
47, XXX Karyotype
Triple X
Also known as Trisomy X, XXX Syndrome.
Triple X
