Down syndrome: signs, symptoms and characteristics


Down syndrome is a genetic disorder in which there is an extra complete or partial chromosome 21. For most people with Down syndrome, this abnormality causes many distinctive physical features, as well as potential health and wellness problems. The exception are those who have a relatively rare form of Down syndrome called mosaic Down syndrome, in which not all cells have an extra chromosome 21. A person with this type of Down syndrome may have all the signs of complete trisomy 21, some of them or theirs, absolutely not.

Many of the features of complete trisomy 21 are quite prominent, for example, a round face and upturned eyes, as well as a short, plump build. People with Down syndrome sometimes move uncomfortably, usually due to low muscle tone (hypotension) at birth, which can interfere with physical development.

Down syndrome is also associated with developmental delays and intellectual disabilities, although it is important to remember that these vary widely.

Technically speaking, parents and doctors look for signs of Down syndrome, not symptoms. They can be seen after the baby is born or, in some cases, in the womb.

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physical characteristics

The first sign that a baby may have Down syndrome may appear during routine prenatal tests . In a mother's blood test, called a quad screen, elevated levels of certain substances can be a red flag for Down syndrome, but it does not mean that the baby definitely has the disorder.

Visible signs

On an ultrasound (picture of a developing fetus, also called an ultrasound), visible signs of Down syndrome in a child include:

  • Excess skin on the nape (occipital transparency)
  • Femur shorter than usual.
  • The nose bone is missing

These signs prompt doctors to recommend amniocentesis or chorionic villus sampling (CVS), both prenatal tests that examine cells taken from amniotic fluid or the placenta, respectively, and can confirm the diagnosis of Down syndrome. Some parents choose these tests and others do not.


People with Down syndrome have many recognizable facial features and appearance. They are most obvious at birth and can become more pronounced over time. The obvious features of Down syndrome include :

  • Round face with a flat profile and a small nose and mouth.
  • Large tongue that may protrude from the mouth.
  • Almond-shaped eyes with skin covering the inside of the eye (epicanthus folds)
  • White spots on the colored part of the eyes (Brushfield spots)
  • Small ears
  • Small head, slightly flattened on the back (brachycephaly).
  • Short neck
  • Clinodactyly – a fold in the palm of each hand (usually two), short and short fingers, and an inward curved little finger.
  • Small feet with a larger space than usual between the thumb and the second toe.
  • Short and chubby build: Babies with Down syndrome are usually medium-sized at birth, but tend to grow more slowly and be smaller than other children their age. People with Down syndrome are also often overweight.
  • Low muscle tone: Babies with Down syndrome often appear "lethargic" due to a condition called hypotension. Although hypotension can improve and often improves with age and physical therapy, most children with Down syndrome generally reach milestones (sitting, crawling, and walking) later than other children. Low muscle tone can contribute to eating and motor retention problems. Younger and older children may have delays in speaking and learning skills such as eating, dressing, and toilet training.

Guidelines for talking with a Down syndrome doctor

Get our printable guide to your next doctor's appointment to help you ask the right questions.

Intelligence and development

All people with Down syndrome have some degree of mental retardation or developmental delay, which means that they tend to learn slowly and may have difficulty with complex reasoning and judgment.

There is a misconception that children with Down syndrome have certain limitations in their ability to learn, but this is completely wrong. It is impossible to predict the extent to which a child born with Down syndrome will be intellectually dysfunctional.

According to the international human rights organization Down Syndrome Education (DSE), related problems can be divided into the following categories :

  • Slow development of motor skills: Delays in reaching milestones that allow a child to move, walk, and use their hands and mouth can reduce their ability to explore and experience the world, which in turn can affect cognitive development and affect language skills. developing.
  • Expressive Language, Grammar, and Speech Clarity: Due to developmental delays in understanding speech, most children with Down syndrome slowly acquire the correct structure and grammar of sentences, according to the DSE. They may also have trouble speaking clearly, even if they know exactly what they are trying to say. This can be frustrating and sometimes lead to behavior problems. It can even lead to an underestimation of the child's cognitive abilities.
  • Number skills: Most children with Down syndrome have a more difficult time mastering number skills than reading skills. In fact, DSE states that the former are typically about two years behind the latter.
  • Short-term verbal memory: Short-term memory is an immediate memory system that retains newly learned information for short periods of time. It supports all educational and cognitive activities and has separate components for processing visual or verbal information. Children with Down syndrome are not as good at retaining and processing information that comes to them verbally as they are at remembering what appears to them visually. This can put them at a particular disadvantage in classrooms where most of the new information is taught through spoken language.

There is no question that people with Down syndrome have lifelong learning potential and that their potential can be maximized through early intervention , a good education, high expectations, and the support of family, caregivers, and teachers. Children with Down syndrome can learn and develop skills throughout their lives. They just hit their targets at different speeds.

Psychological characteristics

People with Down syndrome are often considered particularly happy, outgoing, and outgoing. While this may be true in general, it is important not to stereotype them, even when it comes to labeling them with such positive characteristics.

People with Down syndrome experience a wide range of emotions and have their own characteristics, strengths, weaknesses, and styles, just like everyone else.

There are some behaviors associated with Down syndrome that are largely related to the unique problems that the condition presents. For example, most people with Down syndrome tend to need order and routine when faced with the complexities of daily life. They thrive on routine and often insist on similarities. This can be interpreted as an innate stubbornness, but this rarely occurs.

Another behavior commonly seen in people with Down syndrome is self-talk, which sometimes everyone does. It is believed that people with Down syndrome often use self-talk as a way to process information and reflect on things .


As you can see, it is difficult to separate some of the signs of Down syndrome from its possible complications. However, keep in mind that while many of the above issues are undeniable concerns, others are simply charting a course for the individual that goes beyond the "norm." People with Down syndrome and their families take everything their own way.

However, people with Down syndrome are more likely than healthy people to have certain physical and mental health problems. These additional concerns can complicate lifelong care.

Hearing loss and ear infections.

According to the Centers for Disease Control and Prevention, up to 75 percent of children with Down syndrome will have some type of hearing loss. In many cases, this may be due to abnormalities in the bones of the inner ear.

It is important to identify hearing problems as early as possible, as poor hearing can be a factor in speech and language delays.

Children with Down syndrome are also at increased risk for ear infections. Chronic ear infections can contribute to hearing loss.

Vision or eye health problems

According to the CDC, 60 percent of children with Down syndrome will have some type of vision problem, such as nearsightedness , farsightedness , strabismus , cataracts, or a blocked tear duct . Half will need to wear glasses.


The National Institutes of Health (NIH) state that "Down syndrome often causes problems with the immune system that can make it difficult to fight infections." For example, babies with this condition have a 62% higher incidence of pneumonia in the first year of life than other newborns.

Obstructive sleep apnea

The National Down Syndrome Society (NSDD) reports that there is a 50 to 100% chance that a person with Down syndrome will develop this sleep disorder, in which breathing temporarily stops during sleep. This condition is especially common in Down syndrome due to physical abnormalities such as low muscle tone in the mouth and upper airways, narrow airways, enlarged tonsils and adenoids, and a relatively large tongue. Often the first attempt to treat sleep apnea in a child with Down syndrome is to remove the adenoids and / or tonsils.

Problems with the musculoskeletal system.

The American Academy of Orthopedic Surgeons lists a number of problems that affect the muscles, bones, and joints of people with Down syndrome. One of the most common is an abnormality of the upper neck called atlantoaxial instability (AAI), in which the cervical vertebrae are displaced. It does not always cause symptoms, but when it does, it can lead to neurological symptoms such as clumsiness, difficulty walking or abnormal gait (such as lameness), pain in the nerves in the neck, and muscle tension or contractions.

Down syndrome is also associated with joint instability, which can easily dislocate the hips and knees.

Heart defects

According to the CDC, about half of all babies with Down syndrome are born with heart defects. They can range from mild problems that may go away on their own over time to serious defects that require treatment or surgery.

The most common heart defect seen in babies with Down syndrome is atrioventricular septal defect (AVSD), holes in the heart that interfere with normal blood flow. AVSD may require surgical treatment.

Children with Down syndrome who are not born with heart problems will not develop them later.

Gastrointestinal disorders

People with Down syndrome tend to be at higher risk for various gastrointestinal problems. One of them, a condition called duodenal atresia , is a deformation of a small tubular structure (duodenum) that allows digested material from the stomach to pass into the small intestine. In newborns, this condition causes bloating in the upper abdomen, excessive vomiting, and lack of urination and defecation (after the first meconium bowel movements). Duodenal atresia can be successfully treated with surgery shortly after birth.

Another gastrointestinal disorder in Down syndrome is Hirschsprung 's disease – the absence of nerves in the colon, which can cause constipation.

Celiac disease, in which intestinal problems develop when someone ingests gluten, a protein found in wheat, barley, and rye, is also more common in people with Down syndrome.


In this condition, the thyroid gland produces little or no thyroid hormone, which regulates bodily functions such as temperature and energy. Hypothyroidism can be present at birth or develop later in life, so regular screenings for this condition should be performed starting with the birth of a baby with Down syndrome. Hypothyroidism can be treated by taking thyroid hormone by mouth.

Blood diseases

These include anemia, in which there is not enough iron in the red blood cells to carry oxygen to the body, and polycythemia (levels of red blood cells that are above normal). Childhood leukemia, a type of cancer that affects white blood cells, occurs in about 2-3% of children with Down syndrome.


According to the NIH, this epileptic disorder most likely occurs during the first two years of a person with Down syndrome or develops after the third decade of life.

About half of people with Down syndrome develop epilepsy after age 50.

Mental health disorders

It's also important to understand that while it may seem like an inherent and unshakable joy, higher levels of anxiety, depression, and obsessive-compulsive disorder have been reported in Down syndrome. These psychological problems can be successfully treated with behavior changes, counseling, and sometimes medications.

Frequently asked questions

  • They have an extra chromosome or part of an extra chromosome. Researchers believe that this extra genetic material affects the growth of the upper jaw (part of the skull), as well as the bones, cartilage and connective tissue of the head, known as the cranial neural crest. This creates common features of Down syndrome, such as upturned, almond-shaped eyes and a smaller head.

  • Many people with Down syndrome have unusually large tongues . In this condition, called macroglossia, the tongue is too big for the mouth, so it sticks out. Because babies born with Down syndrome also have muscle control problems (and the tongue is a muscle), this condition can be particularly noticeable and troublesome.

  • People with Down syndrome experience a wide range of emotions and are not always happy. In general, the vast majority of people with Down syndrome report that they are satisfied with their lives and that they like who they are.

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