What is the difference between autism and Down syndrome?

Dear Dr Ombeva,

I read your recent article on autism and found it informative. My brother’s son of four years has Down syndrome. This was diagnosed when he was very young.

However, we recently visited a doctor who said he has autism and not Down syndrome. Now we are confused. Could be that he has both autism and Down syndrome? What is the difference between the two conditions?

The boy was born normally and even breastfed normally, but had a face appearance and hole in the heart which we were told are signs of Down syndrome. We later realised he delayed speaking, and words were not coming out clearly.

He does not want to play with other kids, and most times, he sits in the corner of the room and just does nothing, or other times he can take a stick and begin hitting the chair repeatedly non-stop.

Peris

Dear Peris,

 Down syndrome is a genetic condition also called trisomy 21. In a trisomy, a person inherits an extra copy of one chromosome. Children with Down syndrome therefore have all or part of a third copy of chromosome 21, and the additional genetic material results in characteristic physical and intellectual features. It is the most common chromosome abnormality in humans and the commonest inherited cause of learning disability.

Down’s syndrome affects all ethnic groups equally, and affects more boys than girls. A child with Down’s Syndrome often looks different from other children, with a flat facial profile and eyes that slant upwards, smaller ears, a flat back of the head and protruding tongue with broad hands with a single crease across the palm.

Almost half of children affected have heart defects. Children with Down’s syndrome have moderate to severe learning disability. Like in autism, there is no cure for Down syndrome. Autism is a brain disorder, present from birth, but cause is unknown.

Children with autism have difficulty in learning language and social skills and in relating to people, and maybe aggressive or show self-injurious behaviour. Usually language is slow to develop, and may include peculiar speech patterns or the use of words without attachment to their normal meaning.

The autistic child often avoids eye contact, and may lack cooperative play with peers, due to an impaired ability to develop friendships, and underlying inability to understand other people’s feelings. Sometimes he may appear deaf or fail to respond to words or sounds; or be distressed by an everyday noise like a vacuum cleaner or a dog’s barking.

An autistic person may show repetition by following the same route, the same order of dressing, or the same schedule every day. Autism can occur alone or in association with other developmental disorders like mental retardation, learning disabilities, epilepsy and Down syndrome.

— Dr Ombeva Malande is a paediatrics and child health expert