Sometimes when meiosis ( the division of reproductive cells ) occurs, chromosomes may be lost, left behind, or too many may be passed on, resulting in the birth of a child with a genetic or congenital defect or disease. One of the most common of these genetic disorders is Down syndrome. This disorder takes its name from Dr. Langdon Down, who was the first to describe it formally, in 1866.
Down syndrome is a condition marked by abnormal physical and mental development that is caused by a genetic defect. This genetic defect is caused by an extra chromosome. People born with Down syndrome have 47 chromosomes compared to the normal amount of 46, 23 chromosomes inherited from each parent. This extra chromosome originates more often in the mother's egg than the father's sperm. Chromosomes are individual, large DNA molecules in a cell nucleus. They contain the genes along with structures that hold the DNA and aid it in expressing heredity by orchestrating cellular operations.
Down syndrome is one of the most common chromosomal abnormalities, occurring in about 1 out of 800 births. However, the frequency of the disorder varies greatly according to the age of the mother. For women in their twenties the rate is 1 in 2,000 but it rises steeply to 1 in 100 by the time a woman reaches 40.
Down syndrome is usually recognized soon after birth because of characteristic facial features such as a flattened nose, upward slanting of the eyes, a large tongue that often protrudes from a smal...
Down’s syndrome is a chromosomal condition that is caused by an extra 21st chromosome as there is an error in the body’s cell division. Every human has a nucleus in every cell in the body which contains genes that are grouped along with chromosomes. The normal number of
Another frame of reference used with Down syndrome children is the motor control approach (Uyanik & Kayihan, 2010). Normal development occurs in stages, normal movement and function is essential to a ...
Most cases of Down syndrome are not inherited. When the condition is caused by trisomy 21, the chromosomal abnormality occurs as a random event during the formation of reproductive cells in a parent. The abnormality usually occurs in egg cells, but it occasionally occurs in sperm cells. An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of chromosome 21. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra chromosome 21 in each of the body's cells.
Down syndrome is a very common disorder now a day’s, but not many know what it actually is. Down syndrome was a topic that was not as common back in that day. “John Langdon Down, an English physician, published an accurate description of a person with Down syndrome. It was this scholarly
It is well known that children have Down syndrome within physical features. They are not different than a person who does not have Down syndrome, but their physical features are quite different such as, facial appearance in the face, which is flatter. They also have a slant within their eyes, smaller ears and protruding tongue which is slightly bigger and suspends out a part from the mouth. (2)
Children with Down Syndrome have distinct physical characteristics. They are short in stature and have a small, round face with a high flattened ...
In 1886, physician John Langdon Down was the first scientist to identify Down syndrome. Down was the administrator of a mental institute for children in Surrey, England. From his observations and work at the institute, he was able to identify a set of children who exhibited characteristics such as short nose, broad flat face, short and broad hands, which are features commonly identified with Down syndrome. He later wrote an essay entitled “Observations of the Ethnic Classification of Idiots” in which he asserts the notion that it was possible to classify different types of health conditions through race. His essay included his now famous classification of what is today known as Down syndrome, which he categorized as the Mongol...
Many people believe, from common knowledge, that having a Down syndrome cannot be prevented and that it is genetic. This was proved w...
Down syndrome, a genetic disorder, is the most common cause for intellectual disabilities, occurring at an average of one out of every 700 births (CDS, 2006). This disorder is caused by the extra chromosome 21 (also known as Trisomy 21). According to Hassold and Sherman (2002), the probability of giving birth to a child with DS is not linked to any race, ethnicity, socioeconomic status or geographic location. Maternal age seems to be the only etiological factor that may cause DS.
of serious impairment. Down syndrome is caused by an extra chromosome 21. It also causes
of the cells, instead of the norm of two. Generally, Down syndrome is not hereditary since it is
As mentioned in the introduction, Down Syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21. The extra genetic material is typically responsible for the alteration of physical development. Some of the most common physical traits of Down Syndrome are distinct facial features such as a upward slanting almond shaped eyes, a seemingly flattened face, a tongue that tends to stick out, and small ears. Some of the other physical traits that are sometimes present are short stature, poor muscle tone, and a crease across the palm of the hand (CDC). Due to the poor muscle tone in their bodies, people who have Down Syndrome are more susceptible to conditions such as obesity and sleep apnea...
Down's Syndrome Down's syndrome is a genetic condition involving an extra chromosome, this change occurs around the time of conception. A person with Down syndrome has forty-seven chromosomes instead of the usual forty-six. A relatively common genetic disorder, Down's strikes 1 out of 600 babies. In 95 percent of all cases, the disorder originates with the egg, not the sperm, and the only known risk factor is advanced maternal age-at age 35, a woman has 1 chance in 117 of having a baby with Down's; at 40, her odds are 1 in 34. Graves, 1990.
"Down syndrome." South African Medical Journal 101.1 (2011): 6. Health Reference Center Academic. Web. 16 Apr. 2014.
From society's perspective, Down syndrome children have become a serious complication in the world. Disabled children with special needs like Down syndrome are not given the directed attention needed for appropriate treatment. In 1862, John Langdon Down characterized Down syndrome as a separate form of mental disability but he broadened his research in 1866. By the 20th century, Downs has become the most recognizable form of mental disability in the world because of the physical characteristics that distinguish their disability (Patterson, 137). Some symptoms include a small-flattened face, bowlegs in some cases, and generally, their tongue is too big for their mouth so it usually hangs outside of their mouth as well as other physical characteristics exemplifies a Down syndrome child (Wedro). Down syndrome, Downs or DS, occurs in children who have an "extra copy of chromosome 21." Ninety-five percent of Down syndrome cases are Trisomy 21 (nondisjunction), four percent are translocation, and one percent is mosaicism. There are roughly 400,000 cases of Downs in the United States toda...