Difference Between Autism and Down Syndrome

Autism vs Down Syndrome

Autism and Down syndrome are well known causes of mental retardation. There are other causes of mental retardation, as well. However, these two are important because Down syndrome represents the pure genetic end of the spectrum while autism represents the purely psychological end. Even though some studies have suggested a genetic link to autism, it remains very doubtful to this date. This article will talk about both autism and Down syndrome in detail highlighting the differences in clinical features, symptoms, causes, tests and investigation, prognosis, and the course of treatment they require.

Autism and Autism Spectrum Disorders

The cause of autism and autism spectrum disorders is due to abnormal development of the nervous system. Autism first appears in childhood or infancy. There are three main symptoms of autism. They are poor social interactions, impairment of communication, and restricted interests and repetitive behaviors. Due to poor interactions, autistic children fail to make friends, play alone, and remain possessive. They find it difficult to speak and express feelings through body language.  They develop a unique set of behaviors that they hardly ever change. They like to stack objects up, line up toys and adhere strictly to a daily routine. Autism symptoms become apparent around one to two years of age. Some children develop normally before regressing. During adulthood,  the signs of autism are rather muted.

There are no laboratory tests to detect autism. According to the facts of autism in the journal of autism and developmental disorders, babbling twelve months, gesturing by twelve months, single word use by sixteen months, regular use of two word phrases by twenty four months, and a loss of language skill at any age make it absolutely essential to investigate autism and autistic spectrum disorders further. Even though about 15% of autistic children have a detectable single gene abnormality, using genetic screening methods are not practical yet.  Metabolic tests and imaging methods may be helpful but not done routinely. 

From 1996 to 2007, the incidence of autism has increased dramatically. In 1996, less than 1 in 1000 children suffered from autism. In 2007 more than 5 children out of 1000 have autism. Autism affects boys more than girls. Previously there was a concern that a certain preservative in vaccines caused autism. Therefore, CDC withdrew all vaccines containing that preservative, but there was no significant change in the disease pattern suggesting that there was no such causative link.

Earlier the treatment for autism starts, better the outcome. The main targets are to improve the quality of life, improve social interactions and communication. The regime should be tailored to the child’s needs. No single method is foolproof. Occupational therapy, social skills therapy, structured teaching, speech and language therapy should be employed as needed in each individual case. Statistics suggest that half the patients with autism get drug therapy. Anticonvulsant use has scientific evidence to back it up but others do not. A clear and present danger of drug use is some may respond abnormally to drug treatment.  Treatment for autism is expensive. A study estimates a lifetime cost of around 4 million USD for one patient on average.

Down Syndrome

Genetic abnormality is the cause of Down syndrome. There are three copies of the chromosome 21 instead of the normal two. Family history of Down syndrome and advanced maternal age increases the risk of Down syndrome in the offspring. Down syndrome can be suspected during intrauterine life. Increased nuchal thickness and increased Alfa-Feto-Protein (AFP) in amniotic fluid and blood suggest its presence. Unique symptoms of Down syndrome can be seen at birth during neonatal examination. Neonatal hypothyroidism is the main differential diagnosis of Down syndrome at this stage. Babies with Down syndrome feature flat occiput, low set ears, upward slanting eyes, flat nasal bridge, epicanthal folds of eyes, large rough tongue, Simian crease of hands, poorly developed middle phalanx of the fifth finger, wide sandal gap, heart defects (ASD, VSD, PDA) and duodenal atresia. Patients with Down syndrome are sub-fertile. Their life expectancy is shorter. There is an increased risk of diabetes, hypercholesterolemia, heart attacks, Alzheimer disease and Parkinson disease in Down syndrome.

What is the difference between Autism and Down Syndrome?

• Autism is a neurodevelopmental disorder with doubtful genetic background while Down syndrome is a genetic one.

• There are no unique external abnormalities in autism while Downs causes a whole lot of them.

• Other than cognitive abnormalities autistic children are medically healthy. Down syndrome causes mental retardation as well as medical illnesses.