This region was associated with several of the major DS phenotypes, including protruding tongue and flat facies (largely a function of hypoplastic mandible and craniofacial skeleton, respectively), short stature, mental retardation, joint hyperlaxity
Does Down syndrome affect a person’s phenotype?
Down syndrome is characterized by extensive phenotypic variability ; while cognitive impairment, muscle hypotonia at birth, and dysmorphic features occur to some extent in all affected individuals, most associated traits occur in only a fraction of affected individuals.
Does Down syndrome affect 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 is the genotype for Down syndrome?
Regular trisomy 21 – also known as standard or free trisomy 21 – in which all the cells have an extra chromosome 21. Around 94% of people with Down’s syndrome have this type.
What is the molecular basis of Down syndrome?
Half the chromosomes come from the egg (the mother) and half come from the sperm (the father). This XY chromosome pair includes the X chromosome from the egg and the Y chromosome from the sperm. In Down syndrome, there is an additional copy of chromosome 21 , resulting in three copies instead of the normal two copies.
Can Down syndrome be prevented?
There’s no way to prevent Down syndrome . If you’re at high risk of having a child with Down syndrome or you already have one child with Down syndrome, you may want to consult a genetic counselor before becoming pregnant.
Can Down syndrome people have kids?
Misconception: People who have Down syndrome cannot have children. Reality: It’s true that a person with Down syndrome may have significant challenges in rearing a child. But women who have Down syndrome are fertile and can give birth to children .
Can a Down syndrome child look normal?
People with Down syndrome all look the same . There are certain physical characteristics that can occur. People with Down syndrome can have all of them or none. A person with Down syndrome will always look more like his or her close family than someone else with the condition.
What are the 3 types of Down syndrome?
The three basic types of Down syndrome are trisomy 21, translocation, and mosaicism . All types of Down syndrome result from irregular chromosomes in some or all of the baby’s cells. These irregularities are caused by abnormal cell division, usually in the egg but sometimes in the sperm, before or after conception.
What are signs of Down syndrome during pregnancy?
- Flat face with an upward slant to the eyes.
- Short neck.
- Abnormally shaped or small ears.
- Protruding tongue.
- Small head.
- Deep crease in the palm of the hand with relatively short fingers.
- White spots in the iris of the eye.
- Poor muscle tone, loose ligaments, excessive flexibility.
Do Down syndrome babies have an extra chromosome?
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.
Is Down syndrome XXY?
Several major chromosomal syndromes with altered numbers of chromosomes were reported, such as Down syndrome (trisomy 21 ), Turner syndrome (45,X) and Klinefelter syndrome (47,XXY).
How Can Down syndrome affect someone?
Down syndrome varies in severity among individuals, causing lifelong intellectual disability and developmental delays . It’s the most common genetic chromosomal disorder and cause of learning disabilities in children. It also commonly causes other medical abnormalities, including heart and gastrointestinal disorders.
Can father’s age cause Down syndrome?
July 1, 2003 — Older fathers may contribute just as much as older mothers to the dramatic increase in Down syndrome risk faced by babies born to older couples. A new study found that older fathers were responsible for up to 50 % of the rise in Down syndrome risk when the mother was also over 40.
Why is Down syndrome not curable?
Because Down syndrome is the result of a genetic anomaly , a cure is not possible at this time. While stories occasionally pop up about alleged gene therapy providing a cure, research is typically focused on addressing specific health concerns associated with Down syndrome.
Can Down syndrome people drive?
Many people with Down Syndrome lead independent lives, this includes being able to drive. If a person with Down syndrome can read and pass a driver’s education class and pass a road test , then they can get a driver’s license. Each case is independent and must be evaluated.
