Table of ContentsView AllTable of ContentsWhat Is It?Physical CharacteristicsLow Muscle ToneIntellectual DevelopmentMotor DevelopmentBehaviorsComplicationsNext in Down Syndrome GuideHow Down Syndrome Is Diagnosed
Table of ContentsView All
View All
Table of Contents
What Is It?
Physical Characteristics
Low Muscle Tone
Intellectual Development
Motor Development
Behaviors
Complications
Next in Down Syndrome Guide
Down syndrome(trisomy21) is agenetic disorderthat affects about one in 700 newborns.Often, people with Down syndrome look the same or related due to distinctive physical characteristics.
This article explains Down syndrome and how it is diagnosed. It discusses Down syndrome’s causes, the physical and cognitive effects of the disorder, and what it means for people living with it.
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What Is Down Syndrome?
Down syndrome is a condition in which a person has an extrachromosome—a thread-like structure made up of protein and DNA. Chromosomes are small “packages” of genes in the body. They determine how the body forms and functions as it grows during pregnancy and after birth.
Types of Down Syndrome
There are three types of Down syndrome. However, you usually can’t tell the difference between each type without looking at the chromosomes because the physical features and behaviors are similar.
Common Physical Characteristics of Down Syndrome
Many people with Down syndrome have features such as a round face, upturned eyes, and a short, stocky build.
Technically speaking, parents and healthcare providers look for signs of Down syndrome, rather than symptoms. These may be seen once a child is born or, in some cases, in utero.
The first indication of Down syndrome can appear during routineprenatal testing. In a blood test called the quadruple screen, elevated levels of certain substances can be a red flag for Down syndrome but are not used to make a definitive diagnosis.
An amniocentesis orchorionic villisampling (CVS) may be recommended. These prenatal tests are used to examine cells taken from the amniotic fluid or the placenta, respectively. They can confirm a diagnosis of Down syndrome. Some parents opt for these tests, while others do not.
Visible Signs of Down SyndromeOn anultrasound(an image of a developing fetus, also called a sonogram), visible signs to suggest Down syndrome may include:Excess skin in the back of the neck (nuchal translucency)A shorter-than-normal femur (thigh) boneA missing nose bone
Visible Signs of Down Syndrome
On anultrasound(an image of a developing fetus, also called a sonogram), visible signs to suggest Down syndrome may include:Excess skin in the back of the neck (nuchal translucency)A shorter-than-normal femur (thigh) boneA missing nose bone
On anultrasound(an image of a developing fetus, also called a sonogram), visible signs to suggest Down syndrome may include:
Down Syndrome Features
People with Down syndrome share a host of recognizablefacial and physical features. These are most apparent at birth and can become more pronounced with time.
The more obvious characteristics of Down syndrome include:
People with Down syndrome sometimes move awkwardly, usually due to low muscle tone (hypotonia) at birth which can interfere with physical development.
Hypotonia often causes babies with Down syndrome to appear “floppy.” The poor muscle tone can and often does improve with age and physical therapy. Still, most children with Down syndrome typically reach developmental milestones—sitting up, crawling, and walking—later than other kids.
Low muscle tone may contribute to feeding problems and motor delays. Toddlers and older kids may have delays in speech and learning skills such as feeding, dressing, and toilet training.
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Types of Genetic Trisomy Disorders
People with Down syndrome usually have an IQ (a measure of intelligence) in the mildly to moderately low range.All people with Down syndrome have some degree of intellectual disability or developmental delay, which means they tend to learn slowly and may struggle with complex reasoning and judgment.
Some of these challenges include:
Kids who have Down syndrome aren’t as able to hold and process information that’s stored in verbal short-term memory. This is an immediate memory system for just-learned information. However, it supports all learning and cognitive activity with visual or verbal information processing, and those with Down syndrome tend to do better with visual information.
This can put them at a special disadvantage in classrooms where most new info is taught through spoken language. Yet people with Down syndrome have the potential to learn across a lifetime, and it can be maximized throughearly intervention, good education, high expectations, and encouragement from family, caregivers, and teachers.
Children with Down syndrome can and do learn, and are capable of developing skills throughout their lives. They simply reach goals at a different pace.
Is Down Syndrome the Same as Autism?Down syndrome and an autism spectrum disorder (ASD) diagnosis are two separate conditions. However, ASD does tend to occur more often in people with Down syndrome,Rett syndrome, and other genetic disorders. ASD is diagnosed in about 16% of people living with Down syndrome.That’s roughly one in six people, compared with one in 44 children in the general population.
Is Down Syndrome the Same as Autism?
Down syndrome and an autism spectrum disorder (ASD) diagnosis are two separate conditions. However, ASD does tend to occur more often in people with Down syndrome,Rett syndrome, and other genetic disorders. ASD is diagnosed in about 16% of people living with Down syndrome.That’s roughly one in six people, compared with one in 44 children in the general population.
Down syndrome also affects the development of motor skills. Delays in reaching milestones that allow children to move about, walk, and use their hands and mouths can lower their opportunities to explore and learn about the world.
Factors that affect motor development include the following:
These three factors contribute to reduced postural control, which affects posture, coordination, and balance, as well as fine motor skills, such as writing, using utensils, and manipulating zippers.
Down Syndrome Behaviors
Down syndrome is often associated with traits like being particularly happy, sociable, and outgoing. This may be true in general, but it’s important to avoid stereotypes, even with such positive characteristics and impressions.
People with Down syndrome experience a full range of emotions and have their own strengths, weaknesses, and styles—just like anyone else.
Some behaviors associated with Down syndrome are largely due to its unique challenges. For example, most people with Down syndrome thrive on routine and insist on sameness when dealing with the complexities of daily life. This can be interpreted as innate stubbornness, but that’s rarely the case.
People with Down syndrome also engage in a lot of self-talk, which everyone does sometimes. It’s thought that self-talk is a way for people with Down syndrome to process information and think things through.
Down Syndrome: Facts and Statistics
Complications of Down Syndrome
Hearing Loss and Ear Infections
Many people with Down syndrome have abnormalities in the bones of the inner ear, and up to 75% of children will have some form of hearing loss.They’re also at an increased risk of chronic ear infections that can contribute to hearing loss.
It’s important to detect hearing problems as early as possible, since being unable to hear well can be a factor in speech and language delays.
Problems with Vision or Eye Health
As many as 60% of children with Down syndrome will have some type of vision problem. These problems include:
About half of all people living with Down syndrome will need vision correction.
Infections
Down syndrome often causes problems in the immune system that can make it difficult for the body to fight off infections. For example, infants with the disorder have a 62% higher rate of pneumonia in the first year of life than do other new babies.
Obstructive Sleep ApneaStudies have suggested that 53% to 76% of children with Down syndrome experience breathing that stops temporarily due to sleep apnea.(This occurs in less than 4% of the general population.) Hypotonia in the mouth and upper airway, narrow air passages, enlarged tonsils and adenoids, and a relatively large tongue contribute to the problem. Often, the first attempt at treating sleep apnea in a child with Down syndrome is the removal of the adenoids and/or the tonsils.
Obstructive Sleep Apnea
Studies have suggested that 53% to 76% of children with Down syndrome experience breathing that stops temporarily due to sleep apnea.(This occurs in less than 4% of the general population.) Hypotonia in the mouth and upper airway, narrow air passages, enlarged tonsils and adenoids, and a relatively large tongue contribute to the problem. Often, the first attempt at treating sleep apnea in a child with Down syndrome is the removal of the adenoids and/or the tonsils.
How to Treat Obstructive Sleep Apnea in Kids and Teens
Musculoskeletal Problems
Down syndrome leads to common issues affecting muscles, bones, and joints.A condition called atlantoaxial instability (AAI) affects the upper neck when vertebrae in the cervical spine become misaligned.
This condition doesn’t always cause symptoms, but when it does, a person with Down syndrome may exhibit:
Down syndrome also is associated with joint instability, leading to hips and knees that may easily become dislocated.
Heart Defects
About half of all babies with Down syndrome are born with heart defects.These can range from mild problems, which may correct themselves over time, to serious defects that will require medication or surgeries.
The most common heart defect seen in infants with Down syndrome is anatrioventricular septal defect(AVSD)—holes in the heart that interfere with the normal flow of blood. An AVSD may need to be surgically treated.
Children with Down syndrome who aren’t born with heart problems will not develop them later in life.
Everything to Know About Congenital Heart Disease
Gastrointestinal Issues
Down syndrome often leads to an increased risk for a variety ofGI problems.One condition is calledduodenal atresia, a deformity of the small tube-like structure (the duodenum) that allows digested material from the stomach to pass into the small bowel.
In a newborn, this condition can cause:
Duodenal atresia can be successfully treated with surgery soon after birth.
Another gastrointestinal condition of note in Down syndrome isHirschsprung disease—an absence of nerves in the colon, which can cause constipation.
Celiac disease—anautoimmune diseasein which the body mistakenly attacks the intestines after eating gluten, a protein found in wheat, barley, and rye—is more common in people with Down syndrome as well.
Hypothyroidism
Hypothyroidismoccurs when the thyroid gland makes little or no thyroid hormone, needed to regulate temperature, energy, and other functions in the body.
How Hypothyroidism Is Treated
Blood Disorders
Down syndrome may lead to blood disorders like anemia, in which red blood cells don’t have enough iron to carry oxygen to the body, orpolycythemiawith higher-than-normal levels of red blood cells.
Childhood leukemia, a type of cancer that affects the white blood cells, occurs in about 2% to 3% of children with Down syndrome.
Seizure Disorders
Epilepsy, a seizure disorder, can occur early or later in life. A person with Down syndrome is most likely to be diagnosed with epilepsy in either the first two years of life or after the third decade.
About half of the people with Down syndrome developepilepsyafter age 50.
Down Syndrome Life ExpectancyThe average life expectancy of someone living with Down syndrome is now more than 60 years, a dramatic rise measured in decades when compared with the 1980s.However, some factors cause life expectancy to vary widely, including race.
Down Syndrome Life Expectancy
The average life expectancy of someone living with Down syndrome is now more than 60 years, a dramatic rise measured in decades when compared with the 1980s.However, some factors cause life expectancy to vary widely, including race.
Mental Health Disorders
It’s also vital to understand that, despite what may appear to be innately unshakeable cheeriness, people with Down syndrome experience higher rates of conditions such as:
These psychological problems can be successfully treated with behavior modification, counseling, and sometimes medication.
Summary
Down syndrome (also called trisomy 21) is a genetic disorder where there is an extra full or partial chromosome 21. This extra copy changes how the body and brain develop, which makes intellectual and motor development more challenging.
Although life expectancy has risen dramatically over the decades, there are numerous complications and health conditions people with Down syndrome are more likely to develop compared to people without the condition.
16 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Mai CT, Isenburg JL, Canfield MA, et al.National population-based estimates for major birth defects, 2010-2014.Birth Defects Res. 2019;111(18):1420-1435. doi:10.1002/bdr2.1589Centers for Disease Control and Prevention.Facts about Down SyndromeBilinguistics.The 6 primary Down syndrome characteristics that impact communication.Down Syndrome Resource Foundation.Math.Richards C, Jones C, Groves L, Moss J, Oliver C.Prevalence of autism spectrum disorder phenomenology in genetic disorders: a systematic review and meta-analysis.Lancet Psychiatry.2015 Oct;2(10):909-16. doi:10.1016/S2215-0366(15)00376-4.Centers for Disease Control and Prevention.Autism Spectrum Disorder: Autism and Developmental Disabilities Monitoring (ADDM) Network.Down Syndrome Resource Foundation.Gross motor development.Children’s Hospital of Philadelphia.‘Self-Talk’ in Adults with Down SyndromeCenters for Disease Control and Prevention.Living with down syndrome.U.S. Department of Health and Humans Services. National Institutes of Health.What conditions or disorders are commonly associated with Down syndrome?National Down Syndrome Society.Sleep & Down Syndrome.American Academy of Orthopaedic Surgeons. OrthoInfo.Down Syndrome: Musculoskeletal EffectsNational Down Syndrome Society.Gastrointestinal Tract & Down Syndrome.American Cancer Society.Risk Factors for Childhood Leukemia.Nationwide Children’s Hospital.Down Syndrome Life Expectancy.Santoro SL, Esbensen AJ, Hopkin RJ, Hendershot L, Hickey F, Patterson B.Contributions to Racial Disparity in Mortality among Children with Down Syndrome.J Pediatr. 2016 Jul;174:240-246.e1. doi:10.1016/j.jpeds.2016.03.023.Additional ReadingAmerican Academy of Orthopaedic Surgeons.Down Syndrome: Musculoskeletal Effects.Centers for Disease Control and Prevention (CDC).Living with Down Syndrome.Centers for Disease Control and Prevention (CDC).About Atrioventricular Septal Defect (AVSD).Holmes, G.Gastrointestinal Disorders in Down Syndrome.Gastroenterol Hepatol Bed Bench. Winter, 2014; 7910: 6-8.National Institutes of Health.What Conditions or Disorders Are Commonly Associated with Down Syndrome?
16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Mai CT, Isenburg JL, Canfield MA, et al.National population-based estimates for major birth defects, 2010-2014.Birth Defects Res. 2019;111(18):1420-1435. doi:10.1002/bdr2.1589Centers for Disease Control and Prevention.Facts about Down SyndromeBilinguistics.The 6 primary Down syndrome characteristics that impact communication.Down Syndrome Resource Foundation.Math.Richards C, Jones C, Groves L, Moss J, Oliver C.Prevalence of autism spectrum disorder phenomenology in genetic disorders: a systematic review and meta-analysis.Lancet Psychiatry.2015 Oct;2(10):909-16. doi:10.1016/S2215-0366(15)00376-4.Centers for Disease Control and Prevention.Autism Spectrum Disorder: Autism and Developmental Disabilities Monitoring (ADDM) Network.Down Syndrome Resource Foundation.Gross motor development.Children’s Hospital of Philadelphia.‘Self-Talk’ in Adults with Down SyndromeCenters for Disease Control and Prevention.Living with down syndrome.U.S. Department of Health and Humans Services. National Institutes of Health.What conditions or disorders are commonly associated with Down syndrome?National Down Syndrome Society.Sleep & Down Syndrome.American Academy of Orthopaedic Surgeons. OrthoInfo.Down Syndrome: Musculoskeletal EffectsNational Down Syndrome Society.Gastrointestinal Tract & Down Syndrome.American Cancer Society.Risk Factors for Childhood Leukemia.Nationwide Children’s Hospital.Down Syndrome Life Expectancy.Santoro SL, Esbensen AJ, Hopkin RJ, Hendershot L, Hickey F, Patterson B.Contributions to Racial Disparity in Mortality among Children with Down Syndrome.J Pediatr. 2016 Jul;174:240-246.e1. doi:10.1016/j.jpeds.2016.03.023.Additional ReadingAmerican Academy of Orthopaedic Surgeons.Down Syndrome: Musculoskeletal Effects.Centers for Disease Control and Prevention (CDC).Living with Down Syndrome.Centers for Disease Control and Prevention (CDC).About Atrioventricular Septal Defect (AVSD).Holmes, G.Gastrointestinal Disorders in Down Syndrome.Gastroenterol Hepatol Bed Bench. Winter, 2014; 7910: 6-8.National Institutes of Health.What Conditions or Disorders Are Commonly Associated with Down Syndrome?
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Mai CT, Isenburg JL, Canfield MA, et al.National population-based estimates for major birth defects, 2010-2014.Birth Defects Res. 2019;111(18):1420-1435. doi:10.1002/bdr2.1589Centers for Disease Control and Prevention.Facts about Down SyndromeBilinguistics.The 6 primary Down syndrome characteristics that impact communication.Down Syndrome Resource Foundation.Math.Richards C, Jones C, Groves L, Moss J, Oliver C.Prevalence of autism spectrum disorder phenomenology in genetic disorders: a systematic review and meta-analysis.Lancet Psychiatry.2015 Oct;2(10):909-16. doi:10.1016/S2215-0366(15)00376-4.Centers for Disease Control and Prevention.Autism Spectrum Disorder: Autism and Developmental Disabilities Monitoring (ADDM) Network.Down Syndrome Resource Foundation.Gross motor development.Children’s Hospital of Philadelphia.‘Self-Talk’ in Adults with Down SyndromeCenters for Disease Control and Prevention.Living with down syndrome.U.S. Department of Health and Humans Services. National Institutes of Health.What conditions or disorders are commonly associated with Down syndrome?National Down Syndrome Society.Sleep & Down Syndrome.American Academy of Orthopaedic Surgeons. OrthoInfo.Down Syndrome: Musculoskeletal EffectsNational Down Syndrome Society.Gastrointestinal Tract & Down Syndrome.American Cancer Society.Risk Factors for Childhood Leukemia.Nationwide Children’s Hospital.Down Syndrome Life Expectancy.Santoro SL, Esbensen AJ, Hopkin RJ, Hendershot L, Hickey F, Patterson B.Contributions to Racial Disparity in Mortality among Children with Down Syndrome.J Pediatr. 2016 Jul;174:240-246.e1. doi:10.1016/j.jpeds.2016.03.023.
Mai CT, Isenburg JL, Canfield MA, et al.National population-based estimates for major birth defects, 2010-2014.Birth Defects Res. 2019;111(18):1420-1435. doi:10.1002/bdr2.1589
Centers for Disease Control and Prevention.Facts about Down Syndrome
Bilinguistics.The 6 primary Down syndrome characteristics that impact communication.
Down Syndrome Resource Foundation.Math.
Richards C, Jones C, Groves L, Moss J, Oliver C.Prevalence of autism spectrum disorder phenomenology in genetic disorders: a systematic review and meta-analysis.Lancet Psychiatry.2015 Oct;2(10):909-16. doi:10.1016/S2215-0366(15)00376-4.
Centers for Disease Control and Prevention.Autism Spectrum Disorder: Autism and Developmental Disabilities Monitoring (ADDM) Network.
Down Syndrome Resource Foundation.Gross motor development.
Children’s Hospital of Philadelphia.‘Self-Talk’ in Adults with Down Syndrome
Centers for Disease Control and Prevention.Living with down syndrome.
U.S. Department of Health and Humans Services. National Institutes of Health.What conditions or disorders are commonly associated with Down syndrome?
National Down Syndrome Society.Sleep & Down Syndrome.
American Academy of Orthopaedic Surgeons. OrthoInfo.Down Syndrome: Musculoskeletal Effects
National Down Syndrome Society.Gastrointestinal Tract & Down Syndrome.
American Cancer Society.Risk Factors for Childhood Leukemia.
Nationwide Children’s Hospital.Down Syndrome Life Expectancy.
Santoro SL, Esbensen AJ, Hopkin RJ, Hendershot L, Hickey F, Patterson B.Contributions to Racial Disparity in Mortality among Children with Down Syndrome.J Pediatr. 2016 Jul;174:240-246.e1. doi:10.1016/j.jpeds.2016.03.023.
American Academy of Orthopaedic Surgeons.Down Syndrome: Musculoskeletal Effects.Centers for Disease Control and Prevention (CDC).Living with Down Syndrome.Centers for Disease Control and Prevention (CDC).About Atrioventricular Septal Defect (AVSD).Holmes, G.Gastrointestinal Disorders in Down Syndrome.Gastroenterol Hepatol Bed Bench. Winter, 2014; 7910: 6-8.National Institutes of Health.What Conditions or Disorders Are Commonly Associated with Down Syndrome?
American Academy of Orthopaedic Surgeons.Down Syndrome: Musculoskeletal Effects.
Centers for Disease Control and Prevention (CDC).Living with Down Syndrome.
Centers for Disease Control and Prevention (CDC).About Atrioventricular Septal Defect (AVSD).
Holmes, G.Gastrointestinal Disorders in Down Syndrome.Gastroenterol Hepatol Bed Bench. Winter, 2014; 7910: 6-8.
National Institutes of Health.What Conditions or Disorders Are Commonly Associated with Down Syndrome?
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