Chromosomes are thread-like structures in our cells, which carry essential genetic instructions for life, passing information from one generation to another. Human cells typically have 23 pairs of chromosomes, but those affected by Down syndrome have an extra copy of Chromosome 21. This condition affects approximately 1 in 1,000 worldwide, influencing the development of the brain and body, and causing developmental delays and intellectual disabilities. Despite these challenges, early interventions and appropriate support can significantly improve the quality of life of those with Down syndrome. In this blog, we explore the causes, symptoms, and management strategies to better manage this lifelong condition. But first, let’s understand the basics.
What is Down Syndrome?
Down syndrome is a genetic condition in which an individual is born with an extra chromosome 21 (partial or full). During cell division, each cell receives 23 pairs of chromosomes, one in each pair from the sperm and the other from the egg. However, individuals with Down syndrome have 47 chromosomes, instead of 46, with the extra copy of Chromosome 21 altering normal development.
Every chromosome contains genetic information crucial for the development and formation of different body parts and structures. The 21st chromosome associated with Down syndrome is the smallest and plays a critical role in relaying information for the brain and body’s development. The presence of an extra chromosome alters the development process, which is why people with Down syndrome have distinct facial features, including a small head, small ears, rounded ears, a short neck, slanted and upturned eyes, and a flat nose bridge. Those affected by Down syndrome experience developmental delays and intellectual disabilities, particularly in language and thinking skills. Some individuals also develop health problems such as hearing loss, sleep apnea, and congenital heart defects.
Even though Down syndrome is incurable, there are several well-established treatments and therapies available to manage the condition, and improve the quality of life of affected individuals.
Types and Causes of Down Syndrome
An extra, partial or whole, copy of Chromosome 21 results in the condition called Down syndrome. This occurs as a random error during the formation of an egg or sperm. There are three types of Down syndrome, that occur due to different genetic changes:
1. Trisomy 21 (Nondisjunction)
This is the most common type of Down syndrome, in which all cells of the body have three copies of Chromosome 21 (trisomy) instead of two. This trisomy disease occurs during foetal development due to an error in cell division.
2. Translocation Down Syndrome
This is a rare type of Down syndrome that occurs when part of Chromosome 21 attaches to another chromosome, typically chromosome 14 rather than existing as a separate chromosome. The total number of chromosomes remains 46, but the extra genetic material causes Down syndrome symptoms. It can occur at conception or at a later stage of development.
3. Mosaic Down Syndrome
This is the rarest type of Down syndrome, in which not all cells contain an extra Chromosome 21. Some contain 46 Chromosomes, while others 47. It is a mild form of Down syndrome.
Down Syndrome Symptoms & Effects
While the symptoms and effects of Down syndrome vary based on the type, the core features remain similar, differing primarily in severity. The symptoms of Down syndrome can be categorised as physical, behavioural, and cognitive symptoms.
Physical Signs of Down Syndrome
Babies with Down syndrome may not show distinct features at birth except for weak muscle tone; physical signs often become more noticeable as the child grows, including:
A flat facial profile
Almond-shaped eyes that slant upward
Short neck and hands
Small ears and mouth
Short height
A single crease in the palms
Short pinky finger pointed towards the thumb
As children with Down syndrome grow up, they may develop additional physical symptoms, including:
Behavioural Symptoms of Down Syndrome
People with Down syndrome experience difficulties in expressing their needs and wants to their families and caregivers. Behavioural symptoms of Down syndrome include:
Difficulty in paying attention
Tantrums
Stubbornness
Obsessive or compulsive behaviours
Mental health concerns, including social withdrawal, anxiety, or depression
Cognitive Symptoms of Down Syndrome
A crucial characteristic of Down syndrome is intellectual and developmental delays, such as speaking their first words, eating food on their own, toilet training, or taking their first steps. Individuals with Down syndrome may display cognitive symptoms such as:
Speech difficulties or delayed speech patterns
Delay in language development
Learning and comprehension challenges
Short attention span
Fine motor skill issues, including buttoning a shirt or writing
Risk Factors for Down Syndrome
While Down syndrome cannot be prevented, understanding the risk factors can help parents make informed decisions through genetic counselling, prenatal testing, and early pregnancy planning. Some of the risk factors for Down syndrome include:
Maternal Age: The likelihood of having a baby with Down syndrome rises significantly with the mother's age, particularly after age 35. This is due to age-related changes in the eggs, which can increase the likelihood of improper chromosome division.
Family History: If either parent carries a balanced translocation, the risk of having a child with Down syndrome increases.
Previous Child with Down Syndrome: Parents who have had one child with Down syndrome are at a slightly increased risk of having another child with the condition.
Genetic Factors: A family history of Down syndrome may indicate a slightly higher likelihood, especially if a close relative (such as a sibling or parent) carries a chromosomal translocation.
Parental Age (Father): While maternal age is a significant risk factor, studies suggest that advanced paternal age (over 40 years) may slightly increase the risk of Down syndrome, though the impact is less significant compared to maternal age.
Diagnosis of Down Syndrome
Down syndrome is usually discovered through prenatal and diagnostic tests during pregnancy; however, it may be diagnosed after birth too. The following are the tests used in the Down syndrome diagnosis:
Prenatal tests
There are two categories of prenatal tests used for Down syndrome diagnosis:
1. Screening tests: These tests provide the likelihood of the child being born with Down syndrome. It may include tests such as:
Ultrasound in the first trimester: To look for extra fluid (nuchal translucency) behind the baby’s neck. It is used in combination with blood tests.
Cell-Free DNA testing: Analysis of foetal DNA extracted from the mother’s bloodstream.
Quad screening: Analysis of hormone levels during the second trimester.
2. Diagnostic tests: These tests provide a confirmation of whether the baby will be born with Down syndrome. Diagnostic tests are typically advised when screening tests are positive.
Amniocentesis: Analysis of amniotic fluid for chromosome 21. It is typically performed between 15-20 weeks.
Chorionic Villus Sampling: Examination of the placental tissue for chromosomal abnormalities. It is typically performed between 10-13 weeks.
Percutaneous umbilical blood sampling (PUBS): Examination of foetal blood for chromosomal abnormalities, typically conducted when other tests (such as amniocentesis and chorionic villus sampling) provide inconclusive results.
Postnatal Diagnosis
Down syndrome may be diagnosed after birth based on physical characteristics and confirmed by:
Down Syndrome Treatment Option
Even though there is no definitive cure for Down syndrome, the life expectancy of individuals with this disorder is an average of 60-plus years. A multidisciplinary team of cardiologists, paediatricians, educators, and therapists are involved in the treatment and care of patients with Down syndrome. Several treatment strategies help individuals manage their health problems and improve their overall well-being. These include:
Medical Interventions
Medical treatments are very effective for treating associated health issues experienced by people with Down syndrome:
Hearing Aids: To assist individuals with hearing loss
Glasses or Eye Surgery: To support individuals with vision impairment, such as cataracts or strabismus
Heart Surgery: To repair congenital heart defects
Medications: Used to manage associated conditions, such as digestive issues, infections, and thyroid issues
Developmental Therapies
To support cognitive and behavioural difficulties experienced by people with Down syndrome, several development therapies are effective, including:
Physical Therapy: Physiotherapy strengthen muscles and bones
Occupational Therapy: Aims to enhance fine motor skills and promote independence in carrying out daily activities
Speech Therapy: Aims to enhance speech and communication skills
Behavioural Therapy: To address deficiencies in social skills
Psychological and Social Support
Therapists and social support groups are crucial for children and adults with Down syndrome. It helps improve their emotional well-being and provides required training for improving social interactions.
Educational Support
Individualised education plans and inclusive educational programmes may be needed to support the learning needs of individuals with Down syndrome. It will help them learn at their own pace without losing access to knowledge due to cognitive difficulties.
Self-Care Strategies for People with Down Syndrome
While children with Down syndrome may rely heavily on caregiver support, older children and adults can adopt proactive self-care strategies to enhance independence and overall well-being. Some effective self-care strategies for individuals with Down syndrome that are beneficial for their physical and mental health include:
Engage in regular exercise for physical and mental well-being
Follow a healthy diet
Get enough sleep and rest
Engage in hobbies and community activities
Attend regular health checkups
Participate in education and vocational training programs
Seek counselling and therapy for managing anxieties and stress
Build a strong network of support system
Conclusion
Down syndrome may not be preventable or curable, but it is manageable. Although the challenges of Down syndrome are significant, proper support from medical professionals, therapists, educators, and caregivers can enable individuals to thrive and live fulfilling lives. Individuals planning pregnancy, expecting parents, and those caring for Down syndrome patients can seek advice from expert paediatricians and other specialists at Artemis Hospitals. To book an appointment, call our customer care at +91-124-451-1111 or WhatsApp us. You can also schedule an appointment through our online patient portal or download and register on the Artemis Personal Health Record mobile app, available for both iOS and Android devices.
Article by Dr. Archana Sharma
Associate Consultant - Neurology
Artemis Hospitals
