Autism Spectrum Disorder – Causes and Diagnosis
This month’s article is a continuation of the information provided last month which gave an overview of Autism Spectrum Disorder and detailed the signs/symptoms that accompany the disorder. Now let’s look at the causes/risk factors and how ASD is diagnosed.

The causes of Autism Spectrum Disorder:

Currently no single known cause for ASD has been identified. The complexity and wide variation of symptoms point to the probability of many causes.

The two main factors for Autism Spectrum Disorder Causes that seem to play a role are:

Genetic problems

  • Those associated with a genetic disorder such as Rett syndrome or Fragile X syndrome
  • Genetic changes that would make a child more susceptible to ASD or that create environmental risk factors
  • Genes that affect brain development or the severity of symptoms

For some these genetic problems seem to be inherited, while others happen spontaneously.

Environmental factors

  • Viral infections
  • Complications during pregnancy
  • Air pollutants

Research is continuing to determine if these factors do indeed trigger Autism Spectrum Disorder(ASD).

The biggest controversy is whether there is a link between ASD and certain childhood vaccinations, especially the measles-mumps-rubella vaccine. Extensive research has not found a link between the two and medical providers caution that avoiding vaccinations can place a child in danger of catching and spreading serious diseases.

Risk factors of Autism Spectrum Disorder

Risk factors of Autism Spectrum Disorder

ASD affects children of all races and nationalities but certain risk factors that increase a child’s risk for the disorder have been identified:

  • Child’s sex – boys are four times more likely to develop ASD than girls
  • Family history – if a family has one child with ASD, there is an increased risk of having another child with the disorder. Parents or relatives of these children often have problems with social/communication skills or also engage in behaviors typical of ASD.
  • Other disorders – children with certain medical conditions (fragile x syndrome, tuberous sclerosis, Tourette syndrome, Rett syndrome) have a higher than normal risk of ASD or ASD-like symptoms.
  • Extreme preterm babies – those born before 26 weeks may have a greater risk
  • Parent’s age – children born to older parents many also have an increased risk for ASD2

Diagnosis of Autism Spectrum Disorder

The wide degree of severity and symptoms makes a diagnosis difficult and there is no specific medical test that will determine if a child has ASD. Diagnosis should be a two stage process:
Autism spectrum disorder symptomsStage one – general screening during well child checkups with a pediatrician or early childhood health care provider. The American Academy of Pediatrics recommends screening at 18 and 24 months of age utilizing developmental tests and specific ASD screening instruments. Children who exhibit some developmental problems are referred for additional evaluation.

Stage two – a thorough evaluation by a team of doctors/health professionals, including a psychologist, neurologist, psychiatrist, speech therapist and others experienced in diagnosing ASD. The team will also determine if other conditions may be causing the child’s symptoms. The outcome of the comprehensive evaluations will help parents/caregivers and the team plan for treatment/interventions that will help the child.


While many parents may be concerned with labeling their child with ASD, the earlier the diagnosis is confirmed, the quicker interventions can begin. Early intervention can:

  • Reduce/prevent the more severe disabilities associated with ASD
  • Improve the child’s IQ, language and everyday functional skills3

Next month – more on Autism Spectrum Disorder, ASD treatment, prognosis and prevention.