Ntypes of down syndrome pdf

Down syndrome ds is a birth defect with huge medi cal and social costs, caused by trisomy of whole or part of chromosome 21. Noonan syndrome is a common genetic disorder that causes multiple congenital abnormalities and a large number of potential health conditions. Down syndrome, trisomy 21, prenatal diagnosis, chromosome abnormality, cellfree. Down syndrome is a chromosomal abnormality associated with several. Although the syndrome had been described thous ands of. About 60 cases of the kyphoscoliosis type of the disease have been found worldwide. For every 1 000 babies born, one will have down s syndrome. The mission of the national down syndrome society is to be the. We explain the condition, its cause, symptoms, and how to diagnose it. Down syndrome international journal of molecular and cellular.

The two other types of down syndrome are called mosaicism and translocation. The diagnosis of down syndrome is usually suspected after birth as a result of the babys appearance. Most affected individuals have characteristic facial. It is the most prevalent genetic dis ease worldwide and the common genetic cause of inte llectual disabilities appearing in about 1 in 4001500 newbo rns. Down syndrome is a condition in which a person is born with an extra copy of chromosome 21. Noonan syndrome american academy of family physicians. It is determined by many factors, but research suggests that there is a higher chance if the mother is older than 35 years of age. Many of these characteristics are found to some extent in the general population. People with down s syndrome have a wide range of abilities.

People with down syndrome can have physical problems, as well as intellectual disabilities. There are many physical characteristics that form the basis for suspecting an infant has down syndrome. There are about 750 babies born with down s syndrome in the uk each year. Half the chromosomes come from the egg the mother and half come from the sperm the father. This is when babies are born with weak muscles and bones. Because of the differing abilities from one individual with down syndrome to the next, it is often assumed that down syndrome is a spectrum disorder. Down s syndrome, and the families will be told what type of down s syndrome their child has. Three types dsaco down syndrome association of central ohio. Epidemiology of down syndrome emory genetics emory university. This type accounts for a small percentage of people with down syndrome about 3%.

Down syndrome occurs in around 1 in every 700 pregnancies. Mosaicism or mosaic down syndrome occurs when nondisjunction of chromosome 21 takes place in one but not all of the initial cell divisions after fertilization. This is because there are other health conditions you may be more likely to have. Down syndrome is a chromosomal abnormality associated with several health conditions including vision anomalies such as refractive, accommodative and vergence anomalies, as well as ocular pathology. Progress has been made in characterizing the specific types of. Other types of ehlersdanlos syndrome are very rare. This additional genetic material alters the course of development and causes the characteristics associated with down syndrome. Down syndrome ds is one of the commonest disorders with huge medical and social cost. Down syndrome is completely different from autism and other spectrum disorders. The genetic basis of down syndrome there are 23 pairs of chromosomes, for a total of 46. Down syndrome ds is the most commonly identified genetic. People with down syndrome have an extra chromosome that impacts how a person looks and their ability to think, learn, and reason. Nowadays, every baby born with ds has a blood chromosome test to confirm the diagnosis.

Mosaicism or mosaic down syndrome occurs when nondisjunction of. Mosaic down syndrome is a rare, less severe form of down syndrome. Trisomy 21 means theres an extra copy of chromosome 21 in every cell. If you have down s syndrome, you should see a gp once a year for a checkup, so they can check your health. This xy chromosome pair includes the x chromosome from the egg and the y chromosome from the sperm. Ds is associated with number of phenotypes including congenital heart defects, leukemia, alzeihmers disease.