What are 4 characteristics of Down syndrome?
Short neck, with excess skin at the back of the neck. Flattened facial profile and nose. Small head, ears, and mouth. Upward slanting eyes, often with a skin fold that comes out from the upper eyelid and covers the inner corner of the eye.
Which of the following is the most common cause of Down syndrome?
The most common form of Down syndrome is called trisomy 21. This is a condition wherein people have 47 chromosomes in each cell instead of 46. An error in cell division called nondisjunction causes trisomy 21. This error leaves a sperm or egg cell with an extra copy of chromosome 21 before or at conception.
What are the behaviors of Down syndrome?
A young child with Down syndrome that presents with persistent oppositional, impulsive, disruptive, irritable, and aggressive behaviors should be considered under a possible mood disorder.
What are the 3 types of Down syndrome?
There are three types of Down syndrome:
- Trisomy 21. This is by far the most common type, where every cell in the body has three copies of chromosome 21 instead of two.
- Translocation Down syndrome. In this type, each cell has part of an extra chromosome 21, or an entirely extra one. …
- Mosaic Down syndrome.
What is the most common cause of Down syndrome quizlet?
About 95 percent of the time, Down syndrome is caused by trisomy 21 — the person has three copies of chromosome 21, instead of the usual two copies, in all cells. This is caused by abnormal cell division during the development of the sperm cell or the egg cell.
Is Down syndrome caused by nondisjunction?
Nondisjunction of chromosome 21 is the leading cause of Down syndrome. Two risk factors for maternal nondisjunction of chromosome 21 are increased maternal age and altered recombination.
What causes Down syndrome in pregnancy?
Down syndrome is usually caused by an error in cell division called “nondisjunction.” Nondisjunction results in an embryo with three copies of chromosome 21 instead of the usual two. Prior to or at conception, a pair of 21st chromosomes in either the sperm or the egg fails to separate.
What are the chromosomal abnormalities in Down syndrome?
Typically, a baby is born with 46 chromosomes. Babies with Down syndrome have an extra copy of one of these chromosomes, chromosome 21. A medical term for having an extra copy of a chromosome is ‘trisomy. ‘ Down syndrome is also referred to as Trisomy 21.
What part of the body does Down syndrome affect?
Down syndrome is a genetic disorder that can affect many different parts of the body. An extra part or whole Chromosome 21 is the cause of Down syndrome. It is the most common chromosomal abnormality. This syndrome can affect the heart, the brain, the hormone system and the skeleton.
What are signs of Down syndrome on ultrasound?
Certain features detected during a second trimester ultrasound exam are potential markers for Down’s syndrome, and they include dilated brain ventricles, absent or small nose bone, increased thickness of the back of the neck, an abnormal artery to the upper extremities, bright spots in the heart, ‘bright’ bowels, mild …