A CASE REPORT OF RARE COMORBID AUTISTIC FEATURES IN A CHILD WITH DOWN SYNDROME

Abstract

Down syndrome, described by Langdon Down in 1866 is the most common chromosomal
abnormality leading to intellectual disability. 95 of cases are due to nondisjunction during meiosis in
chromosome 21 and has been one of the most investigated subject in the field of intellectual
disability. Otherwise called Trisomy 21, the incidence varies from 1 in 2500 in women 30 years old to
1 in 32 in women 45 years old. According to the literature, Autism and pervasive developmental
disorders appear to be relatively rare in Downs syndrome. Autistic disorder, also known as infantile
autism, was first described by Leo Kanner in 1943. It is reasonable to say that 1 in every 800 to 1000
children may have autism and male children are 3-4 times affected than female children. The criteria
for autistic disorder comprises qualitative impairment in social interaction and communication, and
restricted , repetitive and stereotyped patterns of behavior, interests, and activities. Autistic disorder
may occur in upto 10 of cases with Downs syndrome, though previously this was not accepted.
Features of Downs syndrome may overlap with that of autistic disorder, but it is important to make out
autistic disorder as this has implications in management. Some key behaviors that may point to the
possibility of autism in a child with Downs syndrome are (1) Extreme autistic aloneness (2) Anxiouly
obsessive desire for the preservation of sameness (3) Lack of eye contact and (4) Shows repetitive,
stereotypical movement. The key area affected developmentally in a child with Downs syndrome is
the cognitive area, the development of thinking, reasoning, and understanding. Delays are expected
in this area. Another area of development is the social and emotional development. These areas
develop more normally in a child with Downs syndrome but not in a child with autism.