Editor’s Note: Each month, Courtagen will feature a disorder or condition that can be diagnosed or identified through one of our multi-gene panels. This month, we are taking a look at Autism Spectrum Disorder, a complex condition for which there are multiple lines of evidence supporting genetic factors play a role in its etiology. Courtagen's devSEEK® Triome, devSEEK®, and devACT® tests target genes associated with neurodevelopmental conditions, including ASD.
Autism spectrum disorder (ASD) is a developmental disability that can cause significant social, communication, and behavioral challenges. Though there are specific diagnostic criteria for ASD, each person differs in regard to their type and severity of symptoms.The long term symptoms and development can also vary among people with autism. The Centers for Disease Control and Prevention (CDC) estimates that 1 in 68 children in multiple communities in the United States have been identified with ASD.
In 2013, the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) was revised to represent a more accurate, consistent, and medically useful way of diagnosing individuals with autism. Prior to this, patients were diagnosed with four separate disorders: autistic disorder, Asperger’s disorder, childhood integrative disorder, and pervasive development disorder not otherwise specified. Now, the DSM-5 considers autism spectrum disorder to be a single umbrella disorder characterized by the following, on a continuum of severity:
- Persistent deficits in social communication and social interaction
- Restricted repetitive patterns of behavior, interests, or activities
- Symptoms are present in the early developmental period
- Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning
- Symptoms are not better explained by intellectual disability or global developmental delay
By age two, many children can be reliably diagnosed with autism, though many children do not receive a full diagnosis until much older. Early diagnosis of autism allows for children to benefit from therapies and behavioral interventions, which can improve symptoms. A child may be suspected of having autism through regular developmental screening during well-child doctor visits, or because of concern by a parent or other caregiver. If a problem is suspected, a child may be referred for a more comprehensive diagnostic evaluation, which may include genetic testing.
Genetics and ASD
ASD is highly heritable, but there is no one single gene or single cause for the disorder. In about 15% of cases, a specific genetic cause of an individual’s autism can be identified. For example, ASD or autistic features can be seen in many different single-gene disorders. These cases can sometimes be referred to as “syndromic autism.” Some of these syndromes include Fragile X syndrome, PTEN macrocephaly syndrome, Rett syndrome, Tuberous Sclerosis Complex (TSC), and Timothy syndrome. Several metabolic conditions can be implicated, such as mitochondrial disorders, untreated PKU, or Smith-Lemli-Opitz syndrome.
In the absence of a known single-gene disorder, ASD likely involves a complex combination of both genetic and environmental factors that influence early brain development. Multi-gene panels, such as Courtagen’s devSEEK® panels, provide clinicians with information on a number of genes commonly associated with ASD and autistic features. Clinicians can then use information from multi-gene panels to tailor treatments that meet the patient’s unique genotype and symptoms.
Meanwhile, Rresearchers are actively trying to identify certain genes that may make a person more susceptible to ASD. This can be done by performing genome-wide and candidate gene association studies. Examples of genes of interest include SHANK3, NLGN3, NLGN4, RELN, and GABRB3, all of which are included in Courtagen’s devSEEK panels.
Resources and Citations
There are a multitude of online resources concerning ASD that can be extremely informative for physicians, scientists, researchers, patients, and caregivers.
- Autism Society (http://www.autism-society.org/)
- Talk About Curing Autism (TACA) (http://www.tacanow.org/)
- Autism Speaks (https://www.autismspeaks.org/)
- Centers for Disease Control and Prevention (http://www.cdc.gov/)
- National Institute of Neurological Disorders and Stroke (http://www.ninds.nih.gov/)
- Simons Foundation Autism Research Initiative (https://sfari.org/)
Lord C, Risi S, DiLavore PS, Shulman C, Thurm A, Pickles A. Autism from 2 to 9 years of age. Arch Gen Psychiatry. 22006; 63(6):694-701
Miles, JH. Autism spectrum disorders-A genetics review. Genetics in Medicine. 2011; 13:278-294.