World Down Syndrome Day, All about the 21 in 21st century

Down Syndrome - Revisiting the basics 

In recent years, genetic disorders have found greater attention in the public discourse. The burden of genetic diseases in India is already a matter of concern and we must address it holistically to ensure that the quality of life of affected people is improved. Down syndrome is a naturally occurring chromosomal arrangement that happens because of the presence of an extra copy of human chromosome 21 in an individual. This extra genetic material causes appearance changes with distinct physical features. 

Interestingly, according to the Centers for Disease Control and Prevention (CDC), the most common chromosomal abnormality globally is still Down syndrome. Every year, approximately 6,000 newborns are born with Down syndrome or roughly one out of every 700 babies. This disease pervades the entire globe- across races, gender, or socioeconomic status, with considerable variation across countries/regions. It is also observed that there is variation in the severity associated with it, and individuals may have a lifelong intellectual disability or developmental delays because of the severity of this syndrome. 

This genetic chromosomal disorder causes learning disabilities in children. It can cause medical abnormalities, like heart and gastrointestinal disorders, in addition, it brings distinct facial features. Some of the more common features include a flattened face, small head, short neck, protruding tongue, upward slanting eyelids (palpebral fissures), unusually shaped or small ears, poor muscle tone, broad, short hands with a single crease in the palm, relatively short fingers and small hands and feet. Additionally, someone with Down syndrome can possess excessive flexibility, tiny white spots on the iris of the eye called Brushfield's spots and short height, etc.

Is it inherited?

It might come as a surprise that most of the time, Down syndrome is not inherited, and very few Down syndrome cases are inherited from one of their parents. In this regard, it is essential to understand the risk factors associated with it.

Risk factors

•    Maternal age: A woman's chances of giving birth to a child with Down syndrome increases with age because of improper chromosome division in the woman’s eggs. A woman's risk of conceiving a child with Down syndrome significantly increases if she conceives after the age of 35. 

•    Carriers of Down syndrome: Both men and women can be carriers of this disease, i.e., they can pass on the genetic information for Down syndrome to their children. This information passed on can result in more than one Down syndrome baby.

•    First child with Down syndrome: Parents who have one child with Down syndrome are at risk of having another child with Down syndrome. A genetic counselor can help parents assess the risk of having a baby with genetic defects.

Medical Complications

•    Heart and Gastrointestinal (GI) defects. About 50% of children with Down syndrome are born with some type of congenital heart defect. The most common heart defect in children is an atrioventricular septal defect (AVSD), meaning a large hole in the center of the heart. A majority of heart defects require surgical or transcatheter intervention, in the early stages. GI abnormalities include issues in the intestines, esophagus, trachea, and anus. GI blockage, heartburn (gastroesophageal reflux), or celiac disease, may also be issued with Down syndrome.

•    Immune disorders. It may lead to some forms of cancer, and infectious diseases, such as pneumonia.

•    Sleep apnea. Obstruction of airways may lead to a greater risk of obstructive sleep apnea. 

•    Obesity. Down syndrome babies/ adults have a tendency to be obese compared with the general population.

•    Spinal problems. Misalignment of the top two vertebrae in the neck puts them at risk of serious injury to the spinal cord. 

•    Other problems. including endocrine problems, leukemia dementia, dental problems, seizures, ear infections, and hearing and vision problems.

Life expectancy

Depending on the severity of health problems, the life expectancy of Down syndrome patients can vary, and can also be similar to that of non-affected people. Someone with Down syndrome these days can even be expected to live for more than 60 years, thanks to all the improved medical care and support systems available today.

Prevention

Since Down syndrome happens because of faulty cell division, sadly, there's no way to prevent it. However, creating more awareness around it and advocating for early diagnosis can help to improve the quality of life of affected people. Women at high risk must be encouraged for getting screening tests done. 

The commonly used procedures for diagnostic testing are Amniocentesis, Chorionic Villus Sampling (CVS), and Ultrasound. However, these methods have limitations. In this context, Next-Generation sequencing (NGS) based screening by NIPT-like methods offer significant advantages and is the most accurate screening option available in the market. NIPT is a more popular approach for screening as it is non-invasive and has zero percent possibility of miscarriage or any other complications with an accuracy rate is 99%. A couple at high risk for having a child with Down syndrome may consult a genetic counselor before becoming pregnant. The counselors can also explain the prenatal tests that are available and help explain the pros and cons of genetic screenings.

To sum up, let us not forget that awareness is only the first step towards addressing this issue. Let us all encourage people we know to get themselves screened and consult a genetic counselor if needed. Early detection would enable better management of the disease and ultimately help to improve the quality of life of affected individuals. Only then we can aim for a society that is more inclusive. This is our answer to this year’s theme of World Down Syndrome Day, “What does inclusion mean?”

By Dr Ashutosh Upadhyay

(Sr. Market Development Manager - Clinical at Premas Life Sciences)

*This article is published by VOH team.*