As reported by WHO, the prevalence of Down syndrome is estimated between 1 in 1,000 to 1 in 1,100 live births throughout the world. It is a congenital disorder that results from an abnormal cell division, resulting in an extra whole or partial copy of chromosome 21. 

Individuals with Down syndrome can lead a better life when they receive parental support, medical care, and proper education through community programmes. Thus, apart from medical aspirants and healthcare professionals, all individuals should know about the causes, symptoms, complications and treatment of this genetic disorder.  

Keep reading for detailed insight!

What is Down Syndrome?

Down syndrome is a genetic disorder that is caused by abnormal cell division, which results in having an extra full or partial copy of chromosome 21. It is the most common genetic chromosomal cause of intellectual disabilities in children. 

The notable complications and physical features of Down syndrome can vary immensely among individuals. While some children need extensive medical care, others can lead a healthy life.

What Causes Down Syndrome?

Down syndrome results from an atypical cell division that involves chromosome 21. There are three distinct genetic alterations that can lead to the development of Down syndrome:

1. Trisomy 21

This condition is responsible for about 95% of cases of Down syndrome. In this, the person carries three copies of chromosome 21 rather than the usual two. The extra chromosome 21 is found in all the cells of the body due to abnormal cell division during sperm or egg formation.

2. Mosaic Down Syndrome

Although quite rare, this condition involves a combination of cells, with some having an additional copy of chromosome 21. This mosaicism results from abnormal cell division following the fertilisation of the egg by the sperm.

3. Translocation Down Syndrome

This occurs in a minimal number of cases when an extra piece of chromosome 21 is joined to another chromosome by a process referred to as translocation. It may occur prior to or during conception. This type of individual has the typical two copies of chromosome 21 and some more genetic material of chromosome 21 attached to an extra chromosome.

What are the Symptoms of Down Syndrome?

Down syndrome is found in both children and adults; however, they exhibit distinctive facial and body features. Although not all individuals with Down syndrome have the same features, there are some common ones, such as:

• A flat facial profile and a short nose with a low nasal bridge
• A shorter neck
• Eyelids that slant upward
• A head that is smaller than normal
• Ears that are small and rounded in shape
• A tendency for the tongue to stick out of the mouth
• A fold of skin on the eyelid, which covers the inner corner of the eye
• White, small spots on the iris, referred to as Brushfield’s spots
• Small and wide hands, usually with a single crease on the palm and short fingers
• Small feet with often a space between the second and first toes
• Muscle tone that is less than normal when an infant is born
• Joints that are loose and exhibit excessive flexibility
• A reduced height
• Hearing loss
• Congenital heart defects 
• Digestive complications

What are the Risk Factors of Down Syndrome?

Although Down syndrome affects people of all races, there are some factors that can raise the risk of a child being born with this condition:

• Maternal Age

Women who are older than 35 years are at greater risk of having a child with Down syndrome, as the risk is higher with increasing age. For women above 40 years of age, the risk is even greater.

• Previous Child with Down Syndrome

Once a woman gives birth to a child with Down syndrome, the likelihood of giving birth to another child with Down syndrome becomes slightly higher.

• Carrier Parent (Translocation)

If a parent has a translocation of chromosome 21, they can pass this on to the child, although they are not affected by Down syndrome themselves. This is uncommon but responsible for a few instances of the condition.

What are the Common Complications of Down Syndrome?

Some Down syndrome children are healthy, but others can have serious health problems. Here are certain medical complications associated with this condition:

• Cardiovascular Problems: Most children with Down syndrome are born with a heart problem. These conditions can be severe and may require surgery soon after birth.
• Gastrointestinal Issues. Certain children exhibit stomach and intestine issues or are at a greater risk of developing gastrointestinal disorders such as intestinal obstructions, gastroesophageal reflux disease (GERD), or celiac disease.
• Sleep Apnea: Individuals with Down syndrome may suffer from obstructive sleep apnea, in which breathing frequently stops while sleeping.
• Immune-related Problems: Due to the differences in their immune systems, people with Down syndrome are at increased risk for autoimmune diseases, certain types of cancer, and infections such as pneumonia.
• Obesity: Individuals with Down syndrome are at higher risk of being obese or overweight than normal people.
• Spinal Problems. Some children have a condition called atlantoaxial instability, in which the upper two neck vertebrae do not align together correctly. This can make them more prone to serious neck spinal cord injuries from activities that force the neck to bend too far, such as contact sports or horse riding.
• Leukaemia: Kids with Down syndrome have an increased likelihood of developing leukaemia.
• Alzheimer’s Disease: People with Down syndrome may develop Alzheimer’s in the later stage of their lives.

In addition, Down syndrome can lead to some other complications such as thyroid issues, dental problems, ear infections, seizures, vision problems, etc. 

What is the Diagnosis Method for Down Syndrome?

The diagnosis of Down syndrome involves both screening and diagnostic tests that determine the risk of the condition, as discussed below:

• Blood Tests

During the first trimester, blood tests determine levels of PAPP-A (pregnancy-associated plasma protein-A) and hCG (human chorionic gonadotropin). Irregular levels may suggest an increased risk for Down syndrome.

• Ultrasound (Nuchal Translucency Test)

An ultrasound is done to assess the nuchal fold at the base of the back of the baby’s neck. If there is excess fluid, it can be a sign of Down syndrome.

• Second Trimester Blood Tests

The second-trimester triple or quad-screen blood test evaluates other substances, such as AFP (alpha-fetoprotein) and estriol, to calculate the risk of Down syndrome.

• Second Trimester Ultrasound

It is a more extensive ultrasound examination that analyses for physical features of Down syndrome, like the thickness of the nuchal fold or other defects.

• Chorionic Villus Sampling (CVS)

Chorionic Villus Sampling (CVS) is a procedure where a sample of placental tissue is taken to determine Down syndrome by examining the chromosomes of the baby. 

• Amniocentesis

A sample of amniotic fluid is removed from the sac that encloses the baby, usually in the second trimester, to check for chromosomal defects.

• Percutaneous Umbilical Blood Sampling (PUBS)

This is an invasive test in which a blood sample is collected from the umbilical cord during the second trimester to screen for genetic disorders.

• Cell-free DNA Testing

This is a non-invasive test that can be performed as early as 10 weeks of pregnancy. It evaluates cell-free DNA from the placenta that circulates in the maternal bloodstream for extra chromosome 21 material. If the test is positive, a diagnostic test is necessary to make the diagnosis.

• Post-birth Diagnosis

Down syndrome is usually diagnosed after birth through a physical examination. If it is suspected, a chromosomal karyotype test is performed to analyse a blood sample for extra chromosome 21, thereby establishing the diagnosis.

What are the Treatment Options for Down Syndrome?

Treatments for Down syndrome aim to improve physical and mental development in all aspects to enable children to perform their best:

• Physical and occupational therapy to improve muscle movement.
• Attending a special education program at school to study self-help skills and social interaction.
• Speech therapy and communication skills appropriate for the child’s age.
• Receiving treatment for associated medical conditions or other conditions such as congenital heart disease or hypothyroidism.
• Wearing glasses for visual correction or hearing aids for hearing impairment.

What are the Tips to Remember While Living with Down Syndrome?

Individuals with Down syndrome can have healthy, productive lives with proper care. Many can live on their own, work, form relationships, and socialise. Additionally, children with Down syndrome can be educated in regular schools with special assistance as necessary. 

To help individuals with Down syndrome excel in their lives, consider the following tips:

• Encourage Progress: Praising people with Down syndrome when they reach new milestones can motivate them and foster their confidence.
• Periodic Health Checks-Ups: Hearing, eyesight, and general health check-ups on a regular basis can ensure the proper well-being of individuals with Down syndrome.
• Clear Communication: Talking calmly and providing valuable advice can facilitate learning and develop the cognitive skills of people with Down syndrome. 
• Interactive Learning: Engaging children with Down syndrome through various activities such as reading, singing, and playing games can develop their communicative skills.
• Establish Routine: For people suffering from this condition, creating routines for daily activities, such as getting up and eating, can make them feel settled and secure.

FAQs About Down Syndrome

1. How long can a person with Down syndrome live?

People with Down syndrome can lead healthy lives up to the 60s, 70s, and beyond. Most have mild to moderate learning disabilities, but some have more significant needs.

2. What are the common features of Down syndrome?

Kids with Down syndrome typically share some physical features, such as a flat face, slanted eyes, small ears, and an out-turned tongue. They also typically have low muscle tone, called hypotonia, which becomes less obvious with age.

3. Does Down syndrome impact sex?

The National Down Syndrome Society (NDSS) states that most people with Down syndrome do have sexual feelings and intimacy needs. These should be recognised and facilitated by caregivers and families in socially acceptable ways that are appropriate for their age.

4. What are the signs of a Down syndrome baby at birth?

When a baby is born with Down syndrome, doctors usually recognise it quickly by checking for certain physical characteristics, including eyes that slant upward, a single crease in the palm, and a wide space between the first and second toes.

5. How high is the risk of trisomy 21 during pregnancy screening?

A normal rate of risk for trisomy 21 on prenatal testing is typically defined as below 1 in 300. In case a pregnant individual gets a result below this figure, they are regarded as low-risk for having a child with Down syndrome.

Conclusion

Down syndrome is a complex genetic disorder that needs to be diagnosed early, treated properly, and supported continuously. It is crucial for aspiring healthcare providers to be aware of its causes, symptoms, and complications to broaden their knowledge and conduct better diagnoses in the future.  

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