Autism Spectrum Disorders

Autism Spectrum Disorders (ASD) are severely incapacitating, life-long disabilities that affect the way in which an individual communicates with others and deals with the world.

shutterstock_117665308Children with ASD physically resemble typically developing children, i.e, they do not have visible physical impairments that make them look obviously different. However, many children with autism have mental retardation. ASD’s could also be associated with other handicapping conditions such as, visual impairment, cerebral palsy or hearing impairment. Some maybe severely affected, while others may appear close to normal and may resemble and individuals with learning problems.

Autism Spectrum Disorders are a class of related developmental disorders that share related characteristics. Each ASD differs from the other by a combination of characteristics that make it unique. Therefore, although they are different they share some similarities. They are clinically distinct and can be diagnosed separately.

Prevalence

Prevalence of ASD has risen dramatically in the last decade. From an earlier estimate of 1 to 4 in 10,000 children, the incidence rate is now approximately 1 in 87 as reported by studies emerging from Europe and USA. This unusual increase may be attributed to biomedical factors and a better understanding of ASD by professionals. India does not have an epidemiological study yet to determine the prevalence of ASD in the country. However, SOPAN is conducting a sample survey in the western region of India to estimate the prevalence of autism in this part of the country. As of date nearly 10,000 families have been covered by this survey which aims for screening and assessment of ASD among children within the age range of 2 to 8 years.

Causes

The assumption that ASD occurred as a result of ‘bad’ parenting has long been done away with. One of the known and proven etiological premises about ASD is that they are genetic. Research findings indicate a strong genetic component. However, there is probably no single gene or genetic defect that is responsible for ASD. Researchers suspect that there are a number of different genes that, when combined together, increase the risk of autism. In families with one child with ASD, the risk of having another child with ASD is 3% to 8%. The concordance of autism in monozygotic twins is 30%. A number of studies have found that first-degree blood relatives of children with autism also have an increased risk of autism spectrum disorders (Dryden-Edwards, 2012). The risk factors for ASD include parental characteristics such as advanced maternal age and advanced paternal age (Gardener et al, 2009). The risk is greater for advanced paternal age. One hypothesis is that this is caused by older sperm that have greater mutation burden; another is that men who carry more genetic liability have some features of autism and therefore marry and have children later. These two hypotheses are not mutually exclusive (Geschwind, 2009) ASD may be due to a number of factors, such as maternal rubella (particularly when deafness and blindness is present), phenylketonuria, encephalitis, meningitis, or co-exist with fragile X syndrome, microcephaly, and tuberous sclerosis (Simpson et al, 2008). Seizures are also common among individuals with ASD (Tuchman, 2003). Additionally, the disorders may result due to the interaction between environmental and genetic factors. Prenatal exposure to insecticides and pesticides, and air pollution (due to vehicular traffic) are suggested as causes of ASD in children (Roberts et al, 2007; Delwiche et al, 2011). Maternal conditions, such as gestational diabetes and metabolic abnormalities double the risk of ASD for the fetus (Gardener et al, 2009).

:: Disorders on the Autism Spectrum
• Autism
• Asperger’s Syndrome
• Rett’s Syndrome
• Childhood Disintegrative Disorder
• PDD-NOS
• Back to autism spectrum disorders main page