Down Syndrome: All You Need to Know

By Dr. Anil Kumar Gulati in Paediatrics (Ped)

Feb 14 , 2024 | 10 min read


Occurring in about 1 in 700 births globally, Down syndrome is a chromosomal anomaly that has a profound impact on the lives of affected individuals. In this article, we aim to explain the multifaceted aspects of Down syndrome, shedding light on its symptoms, causes, and management practices. By delving into the practicalities and nuances, our exploration aims to foster understanding, challenge stereotypes, and underscore the significance of effective management of the condition in order to improve the quality of life for affected individuals. Let’s begin.

What Causes Down Syndrome?

Our genes are responsible for all mental and physical traits. So, an additional genetic material that alters the course of development, causing features of “Down syndrome”. To put it in simple terms, the individual will have 47 chromosomes (one extra) instead of 46. The extra copy of chromosome 21, also called Trisomy 21, gets three copies instead of two. This extra copy of the partial or whole chromosome results in the characteristic of Down syndrome. The genetic

material alters the course of development. Due to the maternal age factor, 80% of children with Down syndrome are born to women under 35 years of age. The additional copy of chromosome 21 originates from the mother in 95% of cases and only 5% have been traced to the father.

The risk of Down syndrome increases with age, from 1 to 1000 at 40 years and 1 in 30 at 45 years of maternal age.

What are the Types of Down Syndrome?

Down syndrome can occur in different forms, and the three main types are trisomy 21, translocation Down syndrome, and mosaic Down syndrome.

Trisomy 21

Trisomy 21 is the most common form of Down syndrome, accounting for about 95% of cases. It occurs when there is an extra copy of chromosome 21 in every cell of the body. Typically, individuals with trisomy 21 have 47 chromosomes instead of the usual 46, with three copies of chromosome 21.


Translocation Down syndrome is less common, accounting for about 3-4% of cases. It occurs when part of chromosome 21 attaches or translocates to another chromosome, often chromosome 14. In translocation Down syndrome, the total number of chromosomes is still 46, but the presence of extra genetic material from chromosome 21 can lead to the characteristic features of Down syndrome.


Mosaic Down syndrome is a rare form, representing about 1-2% of cases. In this type, individuals have a mixture of cells with a normal number of chromosomes and cells with an extra copy of chromosome 21. The degree of mosaicism can vary, and individuals with mosaic Down syndrome may exhibit milder symptoms compared to those with full trisomy 21.

Each type of Down syndrome presents unique challenges and variations in the severity of symptoms. In addition, it's important to note that the specific type of Down syndrome does not necessarily predict the individual's abilities or potential.

The features are almost the same in all varying degrees but milder and fewer in mosaic cases as compared to Trisomy 21. Dr. Asha Rawal, Senior Consultant, Obstetrics and Gynecology, Max Healthcare Pitampura explains: “In standard Trisomy 21, 95% of cases have no egg formation or sperm results in an extra chromosome, nondisjunction. In mosaic Trisomy 21, 2%, not every cell in the body has an extra chromosome or some may be normal with the usual two copies. Translocation trisomy, 3%, whole or part of chromosome 21 is present but attached or translocated to a different chromosome and not chromosome 21.”

What are the Risk Factors for Down syndrome?

Though the occurrence of Down syndrome is usually spontaneous and not directly influenced by external factors, there are certain factors that may increase the likelihood of having a baby with Down syndrome. These include:

  • Maternal age: The most significant risk factor for Down syndrome is maternal age. The chance of having a baby with Down syndrome increases as the mother's age advances, particularly for women over the age of 35. However, the majority of babies with Down syndrome are born to mothers under the age of 35, simply because younger women have more births.
  • Previous child with down syndrome: Women who have previously given birth to a child with Down syndrome have a slightly increased risk of having another baby with the condition.
  • Genetic carrier parents: In rare cases, parents may be carriers of a balanced translocation of chromosome 21, increasing the risk of having a child with Down syndrome.
  • Race and ethnicity: Down syndrome can occur in individuals of all races and ethnicities. However, some studies suggest that there may be variations in prevalence among different ethnic groups.

It's crucial to note that the majority of babies with Down syndrome are born to mothers who are younger than 35 years old, as this age group has more births overall. The risk increases with maternal age, but the condition can still occur in younger mothers. It's important for individuals to discuss their specific risk factors with a specialist, especially during prenatal care.

What are the Signs and Symptoms of Down Syndrome?

Down syndrome leads to certain physical, cognitive, and behavioural characteristics. It's important to note that individuals with Down syndrome can vary widely in their abilities and development. Here are the typical symptoms associated with Down syndrome:

Physical Signs of Down syndrome

  • Distinctive facial features: Individuals with Down syndrome often have characteristic facial features, including almond-shaped eyes, a flat nasal bridge, and a small mouth.
  • Hypotonia (low muscle tone): Babies with Down syndrome may exhibit reduced muscle tone, which can impact motor skills development.
  • Short stature: Individuals with Down syndrome tend to be shorter in stature compared to the general population.
  • Single palmar crease: Instead of the typical three creases in the palm, individuals with Down syndrome may have a single crease.

Cognitive Symptoms of Down syndrome

  • Intellectual disability: Most individuals with Down syndrome have mild to moderate intellectual disability. However, there is significant variability in cognitive abilities among individuals with Down syndrome.
  • Delayed development: Children with Down syndrome may reach developmental milestones, such as crawling, walking, and talking, at a later age than their peers.

Behavioural Symptoms of Down syndrome

  • Social challenges: Individuals with Down syndrome may face challenges in social situations, including difficulty understanding social cues and forming peer relationships.
  • Communication difficulties: Speech and language development can be delayed, and some individuals may have difficulty with expressive language.
  • Repetitive behaviours: Some individuals with Down syndrome may exhibit repetitive behaviours or routines.
  • Stubbornness or rigidity: A tendency toward routine and resistance to change is observed in some individuals.

In addition, individuals with Down syndrome may have various anomalies such as cardiac, gastrointestinal or endocrine defects with poor immune functions.

What are the Complications of Down Syndrome?

Down syndrome is associated with a range of potential complications, affecting various aspects of an individual's health and development. While the severity and occurrence of complications can vary widely among individuals with Down syndrome, common issues include:

  • Cardiovascular issues: Heart defects are relatively common in individuals with Down syndrome. These defects may require surgical intervention, and regular cardiac monitoring is essential.
  • Respiratory issues: Respiratory issues, such as recurrent respiratory infections and increased susceptibility to respiratory illnesses, are more common in individuals with Down syndrome.
  • Gastrointestinal issues: Gastrointestinal anomalies, such as gastrointestinal blockages or malformations, may occur in some individuals.
  • Motor function issues: Low muscle tone (hypotonia) is a common feature in infants with Down syndrome, affecting motor development and coordination.
  • Orthopaedic issues: Musculoskeletal problems, including joint instability, scoliosis (curvature of the spine), and hip dysplasia, are more prevalent in individuals with Down syndrome.
  • Endocrine disorders: Thyroid dysfunction and an increased risk of diabetes are more common in individuals with Down syndrome.
  • Hearing and vision impairments: Hearing loss and vision impairments, including refractive errors and cataracts, may be more prevalent.
  • Dental issues: Dental problems, such as delayed eruption of teeth, misalignment, and an increased risk of gum disease, are common.
  • Mental health disorders: Individuals with Down syndrome may develop mental health disorders such as attention-deficit/hyperactivity disorder (ADHD), anxiety, and depression.
  • Early-onset Alzheimer's disease: Individuals with Down syndrome have an increased risk of developing Alzheimer's disease, often at an earlier age than the general population.

It's important to note that while these complications are associated with Down syndrome, not every individual will experience all of them, and the severity can vary.

How is Down Syndrome Diagnosed?

Before birth

There are two categories of tests for Down syndrome that can be performed before a baby is born.

  • Screening: Screening tests like blood tests and ultrasound are easily available to all pregnant women. The blood/serum tests are a Double marker at 11-13.6weeks, Triple and Quadruple marker done at 15 to 20 weeks. These tests are often performed in conjunction with a detailed ultrasonography to check for “markers “of Down syndrome. New advanced prenatal screen is now available which detects chromosomal material of foetal origin from mother’s blood. This test offers high accuracy up to 99.9%.
  • Diagnostic tests: The diagnostic tests available are Chorionic Villus Sampling (CVS) and Amniocentesis. These procedures carry up to 1% risk of miscarriage but are nearly 100% accurate. CVS is carried out at 9-14 weeks and amniocentesis between 16 to 20 weeks of pregnancy.

At birth

Down syndrome at birth is diagnosed by identifying the physical traits and confirming by chromosome analysis, called “Karyotype” from the blood sample of the baby.

What Impact does Down Syndrome have on Parents and Society?

Children with Down syndrome have cognitive, intellectual delays that may be mild or moderate. There can be structural congenital defects also. Children with this syndrome are accepted by society and organisations. Due to the medical advancements, children with Down syndrome are living longer than before.

How is Down Syndrome Treated?

Down syndrome is a genetic condition, and there is no cure for it. However, individuals with Down syndrome can benefit from various treatments and interventions aimed at managing specific health concerns, promoting development, and improving overall well-being. Treatment plans are typically individualised based on the specific needs of each person. Here are key components of the approach to managing Down syndrome:

  • Early intervention: Early intervention, including physical therapy, occupational therapy, and speech-language therapy, can be crucial in addressing developmental delays and promoting motor skills, communication, and daily living activities.
  • Specialised education: Tailored educational programs and individualised education plans (IEPs) can help support academic development and address learning challenges. Inclusive educational environments are encouraged to promote social integration.
  • Speech and language therapy: Speech and language therapy can help individuals with Down syndrome improve communication skills, speech clarity, and language development.
  • Behavioural therapy: Behavioural therapy and counselling may be beneficial in addressing behavioural challenges, anxiety, and mental health concerns. Early intervention can help individuals develop coping strategies and social skills.
  • Cardiac care: Individuals with Down syndrome often undergo cardiac evaluations and, if necessary, surgical interventions to address congenital heart defects.
  • Orthopaedic care: Monitoring and addressing orthopaedic concerns, such as joint instability and musculoskeletal issues, are important for promoting mobility and preventing complications.
  • Hearing and vision care: Regular hearing and vision screenings, along with appropriate interventions such as hearing aids or glasses, can help address sensory impairments.
  • Dental care: Routine dental care is important for managing dental issues associated with Down syndrome, including delayed eruption of teeth and oral hygiene.
  • Healthcare monitoring: Regular medical check-ups are essential for monitoring overall health and addressing specific health concerns. This includes screening for common health issues associated with Down syndrome, such as heart defects, hearing loss, and vision problems.
  • Supportive services: Supportive services, including social services and community support programs, play a vital role in promoting inclusion, independence, and a supportive social environment for individuals with Down syndrome and their families.

It's important for individuals with Down syndrome to receive comprehensive, coordinated care from a team of healthcare professionals, including paediatricians, therapists, educators, and specialists. Collaborative efforts involving the individual, their family, and healthcare providers contribute to optimising the quality of life and potential for individuals with Down syndrome.

Final Words

While there is no cure for Down syndrome, the spectrum of interventions and support available can significantly enhance the quality of life for those affected. A multidisciplinary approach can make a profound impact on individual development and well-being. For families seeking expert guidance and personalised care, the search ends at Max Hospitals. Our experienced team, equipped with state-of-the-art facilities and a commitment to offer compassionate care, ensures that individuals with Down syndrome receive the best possible interventions and have an improved quality of life. For specialised care and support, consult the specialists at Max Hospitals, where we prioritise the well-being and individual needs of those touched by this life-altering disorder.