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The Difference Between Autism And Down’s Syndrome

Down’s syndrome is one of the most common chromosomal conditions diagnosed in the United States. Approximately 6,000 babies born in the USA every year have Down’s syndrome, which means it occurs in about one in every 700 babies. Similarly, autism remains the most common neurological complication in the USA. 

The Centers for Disease Control and Prevention (CDC) issued its ADDM autism prevalence report in 2020, which deduced that the prevalence of autism had increased to 1 in every 54 individuals. This makes it twice as high as the 2004 rate of 1 in every 125 individuals.

Because of a similarity in their signs and symptoms, autism is seldom related to Down’s syndrome. This article aims to brief you about the specifics of both these disorders and root out the differences between the two. Let’s get right into it.

What is Down’s Syndrome?

Down’s syndrome is a genetic condition in which an individual has an extra chromosome. This condition causes mild to serious developmental, intellectual, and physical complications.

Chromosomes, put simply, are the small packages of genes in our body that determine an individual’s physical traits, intellectual capabilities, and even some personality traits. 

An average human baby is born with 23 pairs or 46 total chromosomes, but babies with Down’s syndrome have an additional copy of chromosome 21, called trisomy 21. This additional chromosome alters the baby’s brain development and body and can cause several severe mental and physical challenges.

All children with Down’s syndrome may look and act similarly but possess different intellectual capabilities. However, all individuals with down’s syndrome have an IQ level (a measure of intelligence) ranging in the mildly to moderately low range and are thus slower to speak and learn than other children.

What are the causes and risk factors for down’s syndrome?

Although research shows that the additional chromosome is the primary cause behind the symptoms of Down’s syndrome, the reason behind the appearance of the extra chromosome is still unknown. Researchers have failed to identify the reasons behind the different factors that play a role in the development of an extra chromosome 21.

One other factor known to increase the risk of Down’s syndrome in a baby is the mother’s age. Women aged 35 or older are more likely to have a pregnancy affected by Down’s syndrome than women who conceive at a younger age. Nevertheless, most babies with Down’s syndrome are born to younger mothers simply because the rate of pregnancies in young women is a lot higher than in older women.

How is Down’s syndrome diagnosed?

Down’s syndrome can be diagnosed via two basic types of tests conducted during pregnancy. These include diagnostic and screening tests. Diagnostic tests usually evaluate whether or not a developing baby would have Down’s syndrome. However, they can prove quite risky for the developing baby and the mother. Common diagnostic tests include:

  1. Amniocentesis: which examines the amniotic fluid surrounding the baby. 

  2. Percutaneous umbilical blood sampling (PUBS): which studies blood from the umbilical cord. 

  3. Chorionic villus sampling (CVS): which examines the components of the placenta. 

Screening tests include a wide array of blood tests and ultrasound procedures that primarily look for the fluid behind a baby’s neck as it can be an indicator of genetic disorders. Although screening tests cannot provide a definitive diagnosis, they can identify whether a woman has a higher or lower chance of birthing a baby with Down’s syndrome. They are also relatively safer for both the developing baby and the mother as compared to other screening processes. 

However, neither diagnostic nor screening tests can evaluate the definite impact of Down’s syndrome on a baby, as it is considered virtually impossible in medicine at present.

What is Autism?

Autism is a complicated and lifelong developmental disability that primarily appears during the early stages of childhood. It can hamper an individual’s social skills, self-regulation, relationships, and communication skills. Autism is a “spectrum condition” that affects different people to varying degrees. Autism is typically defined by a specific set of behaviors and tendencies that can be seen in a majority of autistic people. Autism is typically called by different names, such as:

  1. Autism Spectrum Disorder (ASD): which is the medical name for autism. 

  2. Autism Spectrum Condition (ASC): which is used as a replacement of ASD. 

  3. Asperger’s (or Asperger, in some cases) syndrome: which people use to describe autistic people who have average or above-average intelligence levels.

Is autism an illness?

Autism is not medically considered an illness or disease. It is simply a condition where an individual’s brain works differently than other people. Autistic people are born with this disorder, and it commonly starts showing during the early childhood stages. If an individual is autistic, they will be autistic their whole life. It is not a reversible condition, and there are no distinct treatments or medications either. Autistic people typically require different forms of therapy and support to help them deal with the ups and Downs of life.

Autistic people can live life to the fullest. Like everyone, autistic people have several things they are good at and several things they struggle with. However, being autistic does not mean that you have to stop living a good life, making friends, having meaningful relationships, or getting an education and job. All you need is some extra help from those around you, and in some cases, professional help as well.

Since autism is a spectrum disorder, autistic people are different from each other. Some of them may not even need any support, whereas some might require professional help.

Difference Between Autism and Down Syndrome

Disorder description

Autism Spectrum Disorder is a neurological condition, the causes of which are relatively unknown. Although there is a genetic factor, this disorder is primarily termed a neurotype.

Individuals with autism may suffer from diminished social interaction and cognition, a regional focus of interests, or a higher or sensitive power of sensation. They may also undergo a delay in cognitive development. Although autism is not considered a disease, there are several abnormal traits of autistic people that are usually not a result of physical health complications.

Down’s syndrome, in contrast, is a genetic condition rather than neurological and results from abnormal chromosomal set up. People with Down syndrome may suffer from learning disabilities, delayed walking or crawling, diminished physical growth, retarded intellectual abilities, short stature, an upward slant to the eyes, mild to moderate reasoning and thought process complications, and certain characteristic facial features. Individuals with Down’s syndrome also face several other physical health problems.

Types of the disorders

Autism or Autism Spectrum Disorder consists of three types, which include:

  1. Pervasive Developmental Disorder, also known as “atypical autism”

  2. Autistic disorder, also known as “classic” autism

  3. Asperger Syndrome

Down’s syndrome, however, occurs due to trisomy 21 or an extra chromosome number 21, and this accounts for approximately 95% of all Down syndrome cases. The remaining 5% of cases are because of certain conditions known as Robertsonian translocation and Mosaicism Down Syndrome.

Robertsonian translocation (ROB) is one of the most common forms of chromosomal rearrangement. It occurs when the participating chromosome breaks apart at their centromere (the constricted region of a chromosome that divides it into a long and short arm). As a result of this breakage, the more extended arm fuses to form a large, single chromosome with a single centromere. 

A person is phenotypically normal but possesses 45 chromosomes in such a case. A person with translocation does not exhibit any abnormal or unique physical characteristics but is most likely to have an offspring who possesses an extra 21st chromosome.

Mosaicism Down Syndrome is typically described as a percentage: twenty separate cells are put under scrutiny in a thorough chromosome study. Children suffer from this disorder if:

  1. Five out of the twenty cells under scrutiny possess the standard number of forty-six chromosomes, and

  2. The remaining fifteen cells possess a total of forty-seven chromosomes because of an extra chromosome number twenty-one.

Causes behind these disorders

Autism spectrum disorder does not occur because of a single, clearly defined cause. It is typically caused due to certain abnormalities in the brain but is also linked to several other underlying medical conditions. These include:

  1. Congenital complications or infections in the pregnant mother, such as Toxoplasmosis, Cytomegalovirus (CMV), and German measles (Rubella). 

  2. Inflammation in the brain, which may be because of bacterial meningitis or Encephalitis (both of which are neurological disorders that occur after birth). 

  3. A lack of enzymes required for metabolic activity (untreated phenylketonuria [PKU]). 

  4. Influenza or multi dose flu preparations. 

  5. Fragile X Syndrome or Tuberous sclerosis, both of which are rare genetic disorders. 

The cause of down’s syndrome is primarily abnormal cell division where individuals get a partial copy of genetic material from chromosome 21 or attain a complete, additional copy. 

This extra chromosome leads to complications in the brain and interferes with the development of typical physical features. Environmental factors do not play any part in Down’s syndrome; whatever the parents did or did not do plays no role in its development.


Individuals with autism exhibit specific symptoms, some of which may be similar to those of Down’s syndrome. The most common ones include:

  1. Impaired reciprocal social engagement and interaction

  2. Disturbed eating or sleeping patterns

  3. Weakened communication skills

  4. A narrow repertoire of activities, behaviors, and interests

  5. Seizures

  6. Compulsive or ritualistic behaviors

  7. Abnormal facial expressions or body postures

  8. Poor of eye contact

  9. Impeded language comprehension abilities

  10. Irregular voice tone and intonation

  11. Monotonous or flat speech

  12. Delay in learning to speak

  13. Disturbances in behavior

  14. Inability to comprehend and abide by social cues and norms

  15. Unflinching focus on one topic, part of toy, or item, or inability to let things go

  16. Lack of empathy

  17. Difficulty in making friends or keeping up with them

  18. Repetitive movements or language

  19. A tendency for atypical nonverbal communication

  20. Inability to carry out a two-way conversation

  21. Preference of parallel or solitary play instead of cooperative or associative play

  22. Preference for predictable, such as defined and structured play instead of make-believe or spontaneous play

  23. Diminished learning or intellectual abilities

  24. Self-abusive or abrupt behavior

  25. Inability to cope with change, such as changes in schedule, residence, or food

  26. Social withdrawal

  27. Use of unusual, odd, or inappropriate words or phrases

Symptoms of Down’s syndrome are primarily physical and somewhat different from autism. They include:

  1. Flattened face or the bridge of the nose

  2. Flaccid or saggy muscles

  3. Loose joints

  4. A protruding and bulging tongue that tends to stick out of the mouth

  5. Almond-shaped eyes slanting upwards

  6. Small ears  

  7. Small feet and hands

  8. Smaller than average pinky fingers that tend to curve towards the thumb

  9. Short and webbed neck

  10. Small spots on the iris (colored part of eyes)

  11. Mild to moderate vision impairment

  12. Inability to hear properly

  13. Obstructive sleep apnea (a medical condition where a person’s breathing stops temporarily while sleeping)

  14. Weak immunity or immune deficiency

  15. Thick and dry skin of the palms and soles

  16. Palmar crease (a single line across the palm of the hand)

  17. Polycythaemia

  18. Shorter than average height

Medications and treatment

Autism is a relatively complicated disorder to treat. There is no specific treatment or medication; medical professionals usually undertake several processes to cope with the symptoms. These treatment processes include:

  1. Cognitive-behavioral therapy

  2. Sensory integration therapy

  3. Applied behavior analysis

  4. Social skills training

  5. Speech therapy

  6. Occupational therapy

Individuals with autism are also prescribed stimulants, anticonvulsants, antidepressants, and antipsychotics to suppress their tendencies and elevate the quality of their life. There are some potential alternative treatments as well, which include a gluten-free intake rich in:

  1. Vitamin C

  2. A combination of magnesium and Vitamin B-6

  3. Omega-3 fatty acids

  4. CBD Oil

  5. Melatonin

  6. Oxytocin

  7. Dimethylglycine

Like autism, there is no specific treatment for down’s syndrome, and medical professionals typically advise various therapies and exercises to combat the symptoms. Some of them include the following:

  1. Educational and Early Intervention therapy

  2. Occupational therapy

  3. Behavioral therapy to deal with emotional challenges that may sometimes be out of control

  4. Speech therapy

  5. Exercises to help stimulate and improve motor skills

  6. Different medical subspecialists depending upon the patient’s requirements, such as cardiologists, endocrinologists, eye specialists, hearing specialists, geneticists, etc.

Not many drugs are available for individuals with down’s syndrome. Doctors typically prescribe amino acid supplements and a medication known as Piracetam.

NeuroX offers their revered patients with the highest quality care from certified neurologists and medical professionals. By becoming a part of the NeuroX family, you can receive affordable neurological and psychiatric care right at your doorstep through online appointment booking. Head over to NeuroX right now to book your slot!

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