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Down syndrome is a genetic disorder that delays in physical and intellectual development. The condition varies in severity, so developmental problems may range from mild to serious.
Down syndrome is the most common genetic cause of severe learning disabilities in children, occurring in one in every 800 infants. Every year, as many as 6,000 babies are born with Down syndrome in the United States. The condition is named after John Langdon Down, the doctor who first identified the syndrome.
There’s no medical cure for this condition. But increased understanding of Down syndrome and early interventions make a big difference in the lives of both children and adults with Down syndrome.
Down’s syndrome is the commonest identifiable cause of intellectual disability, accounting for around 15-20% of the intellectually disabled population.
It is believed that people with Down’s syndrome have always existed. However, it was not until 1866 that the English doctor, John Langdon Down, first described the condition, which subsequently took his name.
Click here to see a related article about the History of Down’s Syndrome
In 1959 Professor Jerome Lejeune, a geneticist in Paris, discovered that Down’s syndrome occurred as a result of a trisomy of chromosome 21. This means that instead of the usual 46 chromosomes in the cells of the body, there is an extra chromosome 21, making 47 chromosomes in all. Since then, other forms of the condition, which are much rarer, have been discovered, such as Translocation and Mosaicism. Approximately 94% of people with Down’s syndrome have standard trisomy 21, 4% have a translocation and 2% mosaic Down’s syndrome.
Signs and Symptoms
Down syndrome is a genetic condition caused by extra genes from the 21st chromosome that result in certain characteristics including some degree of mental retardation, or cognitive disability, and other developmental delays. The incidence of Down syndrome in the United States is about 1 in 1,000 births. There is no association between Down syndrome and culture, ethnic group, socioeconomic status or geographic region.
Age-related Risks
Generally, the chance of having a Down syndrome birth is related to the mother’s age. The odds of having a child with Down syndrome at age 35 are about 1 in 350. Under age 25, the odds are about 1 in 1,400. At age 40, the odds are about 1 in 100.
Types of Down Syndrome
There are three types of Down syndrome:
Trisomy 21 — An estimated 95 percent of people with Down syndrome have Trisomy 21, meaning an individual has three instead of two number 21 chromosomes. We normally have 23 pairs of chromosomes, each made up of genes. During the formation of the egg or the sperm a woman’s or a man’s pair of chromosomes normally split so that only one chromosome is in each egg or sperm. In Trisomy 21, the 21st chromosome pair does not split and a double-dose goes to the egg or sperm. An estimated 95 percent to 97 percent of the extra chromosome is of maternal origin.
Trisomy 21, better known as Down syndrome, is the most common chromosomal abnormality in humans. People with Down syndrome vary widely in how they are affected, but health problems and lagging development are common. Children with Down syndrome are special needs children who require special parents. The following are some guidelines that my wife and I have subscribed to. We hope they will help you with your journey.
Diagnosis
Down syndrome is usually identified at birth or shortly thereafter. Initially the diagnosis is based on physical characteristics that are commonly seen in babies with Down syndrome. These include low muscle tone, a single …
