What is the phenotype of trisomy 21?

What is the phenotype of trisomy 21?

‘ Down syndrome is also referred to as Trisomy 21. This extra copy changes how the baby’s body and brain develop, which can cause both mental and physical challenges for the baby. Even though people with Down syndrome might act and look similar, each person has different abilities.

How does Down syndrome affect a phenotype?

(A) A trisomic gene or genes might directly affect cellular function in a fully differentiated cell to cause a functional phenotype of DS or in an immature cell to produce a developmental phenotype. (B) Trisomic genes may alter expression of disomic genes, leading to a cellular manifestation and a DS phenotype.

What are the phenotypic characteristics of Down syndrome?

People with Down syndrome often have a characteristic facial appearance that includes a flattened appearance to the face, outside corners of the eyes that point upward (upslanting palpebral fissures ), small ears, a short neck , and a tongue that tends to stick out of the mouth.

What is the genotype of trisomy 21?

Trisomy 21 (47,XY,+21) is caused by a meiotic nondisjunction event. A typical gamete (either egg or sperm) has one copy of each chromosome (23 total). When it is combined with a gamete from the other parent during conception, the child has 46 chromosomes.

What is the difference between genotype and phenotype?

A person’s genotype is their unique sequence of DNA. More specifically, this term is used to refer to the two alleles a person has inherited for a particular gene. Phenotype is the detectable expression of this genotype – a patient’s clinical presentation.

Is Down syndrome a genotype or phenotype?

Down syndrome (DS) is one of the most frequent congenital birth defects, and the most common genetic cause of mental retardation. In most cases, DS results from the presence of an extra copy of chromosome 21. DS has a complex phenotype, and a major goal of DS research is to identify genotype–phenotype correlations.

What does a positive trisomy 21 mean?

A “screen positive” result for trisomy 21 means that the chance that your pregnancy has this chromosome difference is higher than 1 in 350.

What means trisomy?

Listen to pronunciation. (TRY-soh-mee) The presence of an extra chromosome in some or all of the body’s cells. This results in a total of three copies of that chromosome instead of the normal two copies.

What is a phenotype disease?

In this context, a phenotype would be any observable characteristic or trait of a disease, such as morphology, development, biochemical or physiological properties, or behavior, without any implication of a mechanism. A clinical phenotype would be the presentation of a disease in a given individual.

What do you mean by phenotype?

The term “phenotype” refers to the observable physical properties of an organism; these include the organism’s appearance, development, and behavior. An organism’s phenotype is determined by its genotype, which is the set of genes the organism carries, as well as by environmental influences upon these genes.

What is your phenotype?

Phenotype refers to an individual’s observable traits, such as height, eye color and blood type. A person’s phenotype is determined by both their genomic makeup (genotype) and environmental factors.

What phenotypic symptoms are produced in an individual due to trisomy 21st chromosome?

Down syndrome is a chromosomal condition that is associated with intellectual disability, a characteristic facial appearance, and weak muscle tone (hypotonia) in infancy. This condition is most often caused by trisomy 21.

How long do trisomy 21 babies live?

Down syndrome is one of the most common genetic birth defects. It affects about 1 in 700 babies. Adults with Down syndrome may live about 60 years, but this can vary.