What effect does Down syndrome have on phenotype?

What effect does Down syndrome have on phenotype?

What effect does Down syndrome have on phenotype?

Down syndrome (DS) is a major cause of mental retardation and congenital heart disease. Besides a characteristic set of facial and physical features, DS is associated with congenital anomalies of the gastrointestinal tract, an increased risk of leukemia, immune system defects, and an Alzheimer-like dementia.

How does trisomy affect 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.

How does Down syndrome affect gene expression?

In Down syndrome, there is a primary transcriptional effect of disruption of chromosome 21 gene expression, without a pervasive secondary effect on the remaining transcriptome. The identification of dysregulated genes and pathways suggests molecular changes that may underlie the Down syndrome phenotypes.

What causes most of the phenotypic abnormalities in someone with Down’s syndrome?

Although usually caused by the presence of an extra chromosome 21, subsets of the phenotypic features of DS may be caused by the duplication of small regions of the chromosome.

Is Down syndrome genotype?

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 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.

What is the genotype of Down syndrome?

Genotype–phenotype correlations in Down syndrome identified by array CGH in 30 cases of partial trisomy and partial monosomy chromosome 21 – PMC. The . gov means it’s official.

What chromosome is affected by 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 is the karyotype for Down syndrome?

Trisomy means three bodies. Figure 36.4 is a picture (karyotype) of the chromosomes from a female with trisomy 21 (47,XX+21). Some people have Down syndrome as a result of a chromosome rearrangement.

Is Down syndrome a genotype or phenotype?

What genes are affected by Down syndrome?

What are the phenotypic effects of Down syndrome?

The screening test can indicate the likelihood a mother is carrying a baby with Down syndrome.

  • The diagnostics test can identify whether your baby has Down syndrome.
  • The initial diagnosis is taken during the child’s birth based on their appearance.
  • What are the traits of Down syndrome?

    Epicanthic folds (extra skin of the inner eyelid,which gives the eyes an almond shape)

  • Upslanting palpebral fissures (slanting eyes)
  • Brachycephaly (a smaller head that is somewhat flattened in the back)
  • What gene or chromosome is affected by Down syndrome?

    In these people, the condition is called mosaic Down syndrome. Researchers believe that having extra copies of genes on chromosome 21 disrupts the course of normal development, causing the characteristic features of Down syndrome and the increased risk of health problems associated with this condition. Most cases of Down syndrome are not inherited.

    What is the karyotype of Down syndrome?

    What karyotype is Down syndrome? The trisomy 21 karyotype figure shows the chromosomal arrangement, with the prominent extra chromosome 21. Trisomy 21 is the cause of approximately 95% of observed Down syndrome, with 88% coming from nondisjunction in the maternal gamete and 8% coming from nondisjunction in the paternal gamete.