Down syndrome (DS or DNS), also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is typically associated with physical growth delays, characteristic facial features and mild to moderate intellectual disability. It's normally connected with physical development waits, feature facial attributes and moderate to medium intellectual handicap. The ordinary IQ of a young adult with Down syndrome is 50, equal to the psychological skill of a 8- or 9-year-old kid, but this may vary widely.

The parents of those affected person are generally genetically ordinary. The additional chromosome happens by chance. The possibility rises from less than 0.1 percent in 20-year-old moms to 3 percent in people age 45. There's absolutely no known behavioral action or ecological aspect that affects the chance. Down syndrome could be recognized through pregnancy by prenatal screening followed by diagnostic testing or following arrival by direct monitoring and genetic testing. Because the introduction of screening, pregnancies using the identification tend to be terminated. Normal screening for health issues common in Down syndrome is advocated during the individual's life.

Down syndrome is a genetic disorder caused when abnormal cell division results in an extra full or partial copy of chromosome 21. This extra genetic material causes the developmental changes and physical features of Down syndrome.

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.

 Better understanding of Down syndrome and early interventions can greatly increase the quality of life for children and adults with this disorder and help them live fulfilling lives.
Symptoms

Every individual with Down syndrome is a person -- intellectual and developmental issues might be mild, moderate or intense. Some poeple are healthy while others have major health problems like severe heart defects.

Kids and adults with Down syndrome possess different facial features. Though not all individuals with Down syndrome have the Very Same attributes, a few of the more prevalent features include:

Poor muscle tone
Broad, short hands with a single crease in the palm
Relatively short fingers and small hands and feet
Excessive flexibility
Tiny white spots on the colored part (iris) of the eye called Brushfield's spots
Short height
Flattened face
Small head
Short neck
Protruding tongue
Upward slanting eye lids (palpebral fissures)
Unusually shaped or small ears
Infants with Down syndrome may be average size, but typically they grow slowly and remain shorter than other children the same age.

Causes

Individual cells normally contain 23 pairs of chromosomes. 1 chromosome in each pair comes from the father, the other out of the own mother.

Down syndrome results when abnormal cell division between chromosome 21 happens. These cell division abnormalities lead to an additional semi or complete chromosome 21. This additional genetic material accounts for the characteristic features and developmental issues of Down syndrome. Any one of three genetic variants can Lead to Down syndrome:

Translocation Down syndrome. Down syndrome may also occur when a part of chromosome 21 becomes connected (translocated) onto a different chromosome, before or at conception. These kids have the normal two copies of chromosome 21, but they also have added genetic material from chromosome 21 attached to a different chromosome.

Trisomy 21. Approximately 95 percent of their time, Down syndrome is brought on by trisomy 21 -- that the individual has three copies of chromosome 21, rather than the normal two copies, in most cells. This is due to abnormal cell division during the development of the sperm cell or even the egg cell.

Mosaic Down syndrome. In this rare form of Down syndrome, a person has only some cells with an extra copy of chromosome 21. This mosaic of normal and abnormal cells is caused by abnormal cell division after fertilization.

There are no known behavioral or environmental factors that cause Down syndrome.

Is it inherited?

The majority of the time, Down syndrome is not inherited. It is caused by a error in cell division during early development of the fetus.

Translocation Down syndrome could be passed from parent to child. But only approximately 3 to 4 percent of kids with Down syndrome have translocation and just a number of them inherited it in among the parents.

When balanced translocations are inherited, the mother or dad gets some rearranged genetic material from chromosome 21 on a different chromosome, but no additional genetic material. This means that he or she has no symptoms or signs of Down syndrome, but might pass an unbalanced translocation on to kids, causing Down syndrome at the kids.

Prevention

There is no way to stop Down syndrome. If you are at high risk of having a child with Down syndrome or you currently have a child with Down syndrome, then you might choose to see a genetic counselor before getting pregnant.

A genetic counselor can help you understand your likelihood of having a child with Down syndrome. They can also clarify the prenatal tests which can be found and help clarify the advantages and disadvantages of testing.



Source: https://aderonkebamidele.com/downsyndrome-causes-symptoms-prevention/