Down Syndrome (Trisomy 21)

Original Editor - Elizabeth Cachia, Shelly Dineen, James Egan, Alex James, Joe Nelmes and David Serafini as part of the Queen Margaret University Project Top Contributors - David Serafini, Kim Jackson, Kalyani Yajnanarayan, Jess Bell, Heather Dimond, Michelle Dineen, Admin, Robin Tacchetti, Shaimaa Eldib, Elizabeth Cachia, Beth Potter, Nupur Smit Shah, Rachael Lowe, Tarina van der Stockt, Lucinda hampton, Kirenga Bamurange Liliane and Naomi O'Reilly

Introduction

Down Syndrome (DS) is a genetic, chromosomal condition. Chromosomes are structures found in every cell of the body that contain genetic material and are responsible for determining anything ranging from eye colour to height. Typically, each cell has 23 pairs of chromosomes. However, in individuals with Down syndrome, there is a full or partial extra copy of chromosome 21 in some, or all, cells.

Epidemiology

DS is the most commonly occurring chromosomal variance noted worldwide, with 1 in 1000 births resulting in a child with DS. In the UK alone, there are approximately 40,000 people living with Down Syndrome, and 750 are born each year with DS . Birth rates are expected to stay the same, but the total population of persons with DS is expected to rise in the coming years. This is mainly due to medical advancements which have increased life expectancy from age 9 in 1929, to 60 years of age today. With this increase in the number and age of this population, there will be a larger demand on health services, such as physiotherapy, and increased challenges for families to overcome.

Signs and Symptoms

Though there are many similarities across the DS population, there is great variation in the syndrome. There are three types of DS: Trisomy 21 (95%), Translocation (3%-4%) and Mosaicism (1%). Whichever the type, persons with DS typically have poorer overall health at a young age and exhibit a greater loss of health, mobility, and increased secondary complications as they age compared to their non-DS counterparts. As a result, persons with DS and their families frequently access a range of health services, including physiotherapy.

Physical Characteristics

• Growth failure
• Hypotonia
• Ligamentous laxity
• Flat posterior aspect of the head
• Broad flat face
• Slanting eyes
• Epicanthic eyefold
• Short nose
• Small and arched palate
• Big wrinkled tongue
• Dental anomalies
• Short and broad hands
• Special skin ridge patterns
• Unilateral/bilateral absence of one rib
• Congenital heart disease
• Intestinal blockage
• Enlarged colon
• Umbilical hernia
• Pelvis anomalies
• Diminished muscle tone
• Big toes widely spread

Medical conditions

DS is not a medical condition, but a common variation in the human form. There are, however, many medical conditions that people with DS frequently experience. These include:

• learning difficulties  
• poor cardiac health  
• thyroid dysfunction  
• diabetes  
• obesity
• digestive problems
• low bone density
• hearing and vision loss
• dementia and Alzheimer's Disease
• depression
• leukaemia

Developmental Milestones and Down Syndrome

Children with Down Syndrome (DS) will generally achieve the same basic motor skills necessary for everyday living and personal independence. However, it may be at a later age and with less refinement compared to those without DS. Some adjusted milestones for DS are listed in the table below:

It is common for children with DS to be delayed in reaching common milestones such as sitting independently, standing and walking. One of the contributing factors to the delay of these specific milestones is poor balance. Balance challenges often follow a child into their teen years and sometimes into adulthood. Impaired balance may also impact the development of other motor abilities and cognitive development. Being able to maintain balance allows for exploration, social interaction and overall freedom.

Some causes of balance difficulties are:

• ligament laxity
• low muscle tone
• slow reaction times/speed of movement
• differences in brain size: a smaller cerebellum impacts function, limits balance reflexes, and causes blurry vision when completing tasks at high speed. Other parts of the brain can also smaller, creating issues with voluntary activities, walking technique and coordination.
• poor postural control

Another contributing factor to delayed milestones and a common challenge for individuals with DS is decreased strength.

During childhood, children with DS do not experience the same amount of muscle growth or strength increase as their peers without DS. Individuals with DS typically have 40-50% less strength. Decreased strength can impact activities of daily living, such as walking upstairs, getting out of a seat etc, but it can also lead to:

• increased wear and tear on joints
• higher risk of falls
• elevated level of fatigue
• delayed developmental milestones
• increased risk of osteoporosis

It can also contribute to reduced balance due to weakness of the stability muscles.

Optionally, learn more about Down Syndrome Developmental Milestones and Physical Activity on this page.

Sensation

In addition to the other challenges facing people with DS, they can also experience sensory issues. Being unable to process sensory information from the environment (i.e. sensory integration) can be both frustrating and challenging, and often leads to inappropriate behaviour as a response. When sensory feedback is limited, it can impact progress in other areas such as motor development. Sensory difficulties can impact a child’s behaviour and the way they interact with people and objects around them.

Mental Health and Emotional Wellbeing

It is not uncommon for individuals with DS to experience challenges with emotional behaviours and mental health. Children with DS may have difficulties with communication skills, problem-solving abilities, inattentiveness and hyperactive behaviours. Adolescents may be susceptible to social withdrawal, reduced coping skills, depression, anxiety, obsessive-compulsive behaviours and sleep difficulties. Adults with DS may have similar experiences as adolescents, with further complications of dementia and Alzheimer's later in life .

Physiotherapy Management and the Role of the Multidisciplinary Team

All members of the multidisciplinary team can play a major role in supporting individuals with DS by adopting a holistic approach to their diverse needs.

Physiotherapists provide tailored interventions to improve physical abilities, strength, and balance, while occupational therapists focus on enhancing daily living skills, fine motor control, and sensory processing. Speech and language therapists help individuals with DS develop effective communication skills and address feeding and swallowing challenges. Psychologists support emotional and cognitive well-being, helping individuals and their families cope with challenges and develop strategies for long-term success.

Effective physiotherapy management of DS typically involves a combination of sensory integration therapy, neurodevelopment treatment, perceptual-motor therapy and traditional strength and conditioning programmes. Physiotherapists educate individuals and their families and provide input on health promotion and long-term condition management. Interventions are based on the individual’s physical and intellectual needs, as well as his or her personal strengths and limitations. Below are some examples of interventions for children with Down syndrome. 

• Tummy time
• Neurodevelopmental treatment (NDT)
• Sensory integration therapy (SIT)
• Perceptual-motor therapy (PMT)
• Two-wheeled bicycle training
• Therapeutic horseback riding (hippotherapy)
• Treadmill training
• Balance training
• Strength training
• Physical activity

As many treatments often require on-going maintenance, the team should encourage family members to support and implement home treatment plans in an attempt to encourage self-management. By fostering strong communication among the team members and families, the multidisciplinary rehabilitation team can make a lasting impact on the lives of individuals with DS, helping them achieve their full potential and lead more independent lives.

Resources

The following “Ted Talk” presented by Karen Gaffney, a person with Down Syndrome, explores numerous contemporary thoughts surrounding DS and challenges society's preconceptions of people with DS.