The condition was first described by Dr John Langdon Down in 1862.
The genetic cause of Down syndrome was discovered in 1959. In 1959 Jérôme Lejeune reported the discovery that Down syndrome resulted from an extra chromosome.
World Down syndrome day:
The General Assembly decided, with effect from 2012, to observe World Down Syndrome Day on 21 March each year. In order to raise public awareness of Down syndrome.World Down Syndrome Day (WDSD), 21 March, is a global awareness day which has been officially observed by the United Nations( UN)since 2012.
Today the average lifespan of a person with Down syndrome is approximately 60 years. As recently as 1983, the average lifespan of a person with Down syndrome was only 25 years.
Down syndrome is caused by a random error in cell division that results in the presence of an extra copy of chromosome 21. The type of error is called non disjunction Trisomy 21.
About 95 % of the time, Down syndrome is caused by Trisomy 21 — the person has three copies of chromosome 21, instead of the usual two copies, in all the cells.
Some of the common medical issues as outlined by the Guidelines for Adults with Down Syndrome include “congenital cardiac and gastrointestinal anomalies, autoimmune conditions, diverse leukemias, respiratory infections, sleep disorders, hearing and vision loss and early development of Alzheimer's type dementia.”
Down syndrome is the most common cause of intellectual disability and every person with Down syndrome will have some level of intellectual disability. There will be some delay in development and some level of learning difficulty. Because everyone is unique, the level of delay will be different for each person.
The estimated incidence of Down syndrome is between 1 in 1000 to 1 in 1100 live births world-wide.
Down syndrome is the most common chromosomal abnormality. It occurs in about 1 in 1,000 babies born each year. In the US this figure is given as 1 in 700 births. In 2015, Down syndrome was present in 5.4 million individuals globally and resulted in 27,000 deaths, down from 43,000 deaths in 1990.
In the 20th century, many individuals with Down syndrome were institutionalized, few of the associated medical problems were treated, and most people died in infancy or early adulthood. With the rise of the eugenics movement, 33 of the then 48 U.S. states and several countries began programs of forced sterilization of individuals with Down syndrome and comparable degrees of disability. Action T4 in Nazi Germany saw the systematic murder of people with Down syndrome made public policy.
The five interesting facts about Down syndrome:
Typical characteristics of Down Syndrome are developmental delays, low muscle tone, almond shaped eyes, flat nasal bridge, short neck, a single palmar crease, small ears, small chin, small feet/hands with short fingers, and shorter height. The average life expectancy of an individual with Down Syndrome today is 60 years.
The factors that increases chance of Down syndrome:
These factors include geographic region, maternal education, marital status, and Hispanic ethnicity. Because the likelihood that an egg will contain an extra copy of chromosome 21, increases significantly as a woman ages, older women are much more likely than younger women to give birth to an infant with Down syndrome.
Down syndrome is a condition in which a person has an extra chromosome. Chromosomes are small “packages” of genes in the body. They determine how a baby’s body forms and functions as it grows during pregnancy and after birth. Typically, a baby is born with 46 chromosomes.
Babies with Down syndrome have an extra copy of one This extra copy changes how the baby’s body and brain develop, which can cause both mental and physical challenges for the baby.
It is well known that the extra chromosome 21 originates from the mother in more than 90% of cases, the incidence increases with maternal age and there is a high recurrence in young women.
Down syndrome occurs in people of all races and economic levels. The risk increases with the mother's age (1 in 1250 for a 25 year old mother to 1 in 1000 at age 31, 1 in 400 at age 35, and about 1 in 100 at age 40). However, 80% of babies with Down syndrome are born to women under age 35 years.A known risk factor for Down syndrome is increasing maternal age, women who are 35 to 39 years old are approximately 4.5 times more likely to have a child with Down syndrome compared with women in the 25 to 29 age group. This risk increases to 15.7 for mothers age 40 years or older.
IQ is a measure of intelligence.People with Down syndrome usually have an IQ in the mildly to moderately low range and are slower to speak than other children.
In general, an IQ score is defined with a median and mean of 100. Scores above 130 are labeled as above average or “very superior,” while scores under 70 would be considered below average or labeled as “borderline impaired.” Most people have an average IQ between 85 and 115.
Most individuals with Down syndrome have mild (IQ: 50–69) or moderate (IQ: 35–50) intellectual disability with some cases having severe (IQ: 20–35) difficulties.
Currently, Ireland tops the countries with the highest rate of Down syndrome prevalence, as its incidence of the syndrome is reported to be 27.5 per 10,000 live births.
Down syndrome remains the most common chromosomal condition diagnosed in the United States. Each year, about 6,000 babies born in the United States have Down syndrome. This means that Down syndrome occurs in about 1 in every 700 babies in USA
According to a 2021 report published in ETHealth, nearly 30,000–35,000 children born in India are said to be affected by Down Syndrome.
In the UK, around one in every 1,000 babies is born with Down syndrome. Anyone can have a baby with Down syndrome, and in most families it appears to be a chance occurrence.
Growth in height is slower, resulting in adults who tend to have short stature—the average height for men is 154 cm (5 ft 1 in), and for women is 142 cm (4 ft 8 inch)
Individuals with Down syndrome are at increased risk for obesity as they age due to hypothyroidism, other medical issues and lifestyle.
Growth charts have been developed specifically for children with Down syndrome.
Some common physical features of Down syndrome are as follows :
•A flattened face, especially the bridge of the nose
•Almond-shaped eyes that slant up
•A short neck
•Small ears
•A tongue that tends to stick out of the mouth
•Tiny white spots on the iris
ingle line across the palm of the hand (palmar crease)
•Small pinky fingers that sometimes curve toward the thumb
•Poor muscle tone or loose joints
•Shorter in height as children and adults.
There is nothing you can do to prevent or avoid your child having Down syndrome. However, your risk is lower if you have children at a younger age.
Screening tests:
A screening test for Down's syndrome, Edwards' syndrome and Patau's syndrome is available between weeks 10 and 14 of pregnancy. It's called the combined test because it combines an ultrasound scan with a blood test. The blood test can be carried out at the same time as the 12-week scan.This test is done between weeks 9 and 11 of pregnancy. Percutaneous umbilical blood sampling (PUBS): A health care provider takes a sample of fetal blood in the umbilical cord through the uterus. The blood is then tested for the extra chromosome.
Amniocentesis is the test we most commonly use to identify chromosomal problems, such as Down syndrome.
Amniocentesis is the test we most commonly use to identify chromosomal problems, such as Down syndrome. (In at-risk fetuses, it can be used to detect other genetic diseases, such as cystic fibrosis, Tay-Sachs disease and sickle cell disease.)
Amniocentesis, chorionic villus sampling (CVS) and ultrasound are the three primary procedures for diagnostic testing.
Screening for Down syndrome can be performed as early as 10 to 14 weeks of pregnancy with a first trimester ultrasound and blood test. Screening can also be performed between 15 and 20 weeks by a blood test referred to as the multiple marker serum screening test.
Screening tests often include a combination of a blood test, which measures the amount of various substances in the mother’s blood (e.g., MS-AFP, Triple Screen, Quad-screen), and an ultrasound, which creates a picture of the baby. During an ultrasound, one of the things the technician looks at is the fluid behind the baby’s neck. Extra fluid in this region could indicate a genetic problem. These screening tests can help determine the baby’s risk of Down syndrome.
Rarely, screening tests can give an abnormal result even when there is nothing wrong with the baby. Sometimes, the test results are normal and yet they miss a problem that does exist.
Diagnostic Tests:
Diagnostic tests are usually performed after a positive screening test in order to confirm a Down syndrome diagnosis. Types of diagnostic tests include:
•Chorionic villus sampling (CVS)—examines material from the placenta
•Amniocentesis—examines the amniotic fluid (the fluid from the sac surrounding the baby)
•Percutaneous umbilical blood sampling (PUBS)—examines blood from the umbilical cord
These tests look for changes in the chromosomes that would indicate a Down syndrome diagnosis.
A blood test looks for what doctors call “markers,” meaning proteins, hormones, or other substances that could be a sign of Down syndrome. Ultrasound looks at the fluid in an area of the baby's neck called the “nuchal fold.” If the fluid level is higher than normal, it could be a sign of Down syndrome.
An ultrasound can detect fluid at the back of a fetus's neck, which sometimes indicates Down syndrome. The ultrasound test is called measurement of nuchal translucency. During the first trimester, this combined method results in more effective or comparable detection rates than methods used during the second trimester.
In the second trimester, the most commonly assessed soft markers include echogenic intracardiac foci, pyelectasis, short femur length, choroid plexus cysts, echogenic bowel, thickened nuchal skin fold, and ventriculomegaly.
Prenatal testing allows you and your family to make informed decisions, including ending the pregnancy. For this reason, before you have the test it's a good idea to think about why you are choosing to do it, and how you will feel once you get the results.
Treatments:
There is currently no way to prevent or cure Down syndrome. There's no specific treatment for Down syndrome. But there is a wide range of physical and developmental therapies designed to help people with Down syndrome reach their full potential. The earlier you start treatment, the better. Each child will have different needs.
The quality of life of people with Down syndrome can be improved by meeting their health care needs, including regular check-ups with health professionals to monitor mental and physical conditions and to provide timely intervention be it physiotherapy, occupational therapy, speech therapy, counselling or special education. Individuals with Down syndrome can achieve optimal quality of life through parental care and support, medical guidance, and community based support systems such as inclusive education at all levels. This facilitates their participation benefits in mainstream society and the fulfillment of their personal potential.
There's no cure for Down syndrome, but treatment is available to help your child reach their full potential. Treatment focuses on helping your child thrive physically and mentally. Treatment options could include: Physical or occupational therapy.
Down syndrome is a lifelong condition. Services early in life will often help babies and children with Down syndrome to improve their physical and intellectual abilities. Most of these services focus on helping children with Down syndrome develop to their full potential. These services include speech, occupational, and physical therapy, and they are typically offered through early intervention programs in each state. Children with Down syndrome may also need extra help or attention in school, although many children are included in regular classes.
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. A genetic counselor can help you understand your chances of having a child with Down syndrome.
Current supplementation policies designed to prevent neural tube defects may incidentally prevent Down's syndrome, provided a sufficiently high dose of folic acid is used.
The new treatment for Down syndrome:
The study drug called ELND005 is believed to have two potential benefits for people with Down syndrome: (1) prevent the accumulation of plaques that might contribute to Alzheimer's disease, and (2) improve working memory and cognitive functioning by regulating myo-inositol levels in the brain.
People with Down syndrome experience pain, both acute and chronic, with at least the same frequency as the rest of the population.
People of all ages with Down syndrome can and do enjoy a variety of relationships with family members, friends, acquaintances, community members, and even sweethearts and spouses.
The detailed account of this genetic defect will be beyond the scope of the article hence author has given breif overview of the syndrome.
Information compiled by:
Dr. Bhairavsinh Raol
