What Is the Broad Autism Phenotype?

The broad autism phenotype (BAP) describes a range of autistic traits that are considered subclinical. That means they are not significant enough to qualify for a diagnosis of autism spectrum disorder.

BAP, also called the broader autism phenotype, is controversial. Some autistic self-advocates and experts see it as either existing in conflict or in harmony with the neurodiversity model.

For a diagnosis of autism spectrum disorder, specific social, verbal, nonverbal, relational, behavioral, and sensorial criteria must be met. However, people with BAP may have traits from a few or all of the categories, with little to no need for support.

This article explains the broad autism phenotype and the traits associated with it. It also discusses how BAP is identified and how it differs from autism.

What Are Broader Autism Phenotype Characteristics?

A phenotype is a set of observable characteristics or traits. Individuals with the broader autism phenotype have autistic traits that do not greatly interfere with an individual's quality of life.

BAP is not an official diagnosis. Instead, it describes a cluster of traits. These traits can show up differently in each individual.

People with BAP show social, non-verbal, verbal, behavioral, sensorial, and relational signs of autism, but not enough to trigger a diagnosis of autism spectrum disorder. They can often pass for allistic or neurotypical (non-autistic) and have little to no support needs.

Broad autism phenotype symptoms and traits may include:

• Difficulties with verbal and nonverbal communication
• Delayed language development during childhood
• Rigid tendencies, like the need for routine
• Aloofness
• Over or under-responsiveness to sensory input
• Fixating on specific interests

How BAP Differs From Autism

Unlike an official autism diagnosis, where specific criteria must be met, BAP has much more wiggle room in terms of how it manifests. Characteristics of BAP and traits of autism both appear within the first year of a person's life.

It is presently impossible to differentiate between BAP and what some people refer to as "high-functioning" autism, leading to some skepticism of the legitimacy of BAP as separate from ASD.

This may be due to masking, a coping mechanism autistic people use to survive in an ableist world. Masking—literally hiding or suppressing autistic traits—can help an autistic person present clinically as BAP, leading to missed autism diagnoses.

How Is the Broad Autism Phenotype Diagnosed?

Broad autism phenotype is not an official diagnosis. To assess you for BAP traits, your healthcare provider or mental health clinician may ask you to take tests like the Social Responsiveness Scale or the Broad Autism Phenotype Questionnaire.

The broad autism phenotype questionnaire is a list of 36 questions about social, verbal, non-verbal, and restricted or repetitive behaviors. Each item has a rating scale to help identify traits of the BAP.

You may answer the test alone or fill it out with the help of your provider. People using the questionnaire are asked to rank themselves on a scale of 1-5 on such statements as:

• I like being around other people.
• I find it hard to get my words out smoothly.
• I am comfortable with unexpected changes in plans.
• I would rather talk to people to get information than to socialize.

Unfortunately, the results of these evaluative questionnaires can vary radically. Because BAP isn't an official diagnosis, it can be difficult to know if you express it.

Working with a healthcare provider or mental health clinician whom you know and trust can help give you insight into the traits or realities you're experiencing.

Can You Be Diagnosed as Autistic if You Have BAP?

Traits of autism can show up within the first year of a person's life. An individual with autism may present with BAP traits that do not rise to the levels of ASD when young.

Later on, when the challenges of school or work increase, a person with BAP may qualify for an autism diagnosis. This can occur because chronic stress can result in autistic burnout, which leaves people with skill regression and less capacity to mask.

But, it's also important to keep in mind that many people have BAP traits and will not go on to be diagnosed with autism spectrum disorder.

Is BAP Genetic?

Studies have shown a very strong genetic, or hereditary, component with the BAP. Specifically, studies show that:

• Individuals related to someone with autism spectrum disorder are more likely than the general public to exhibit traits of autism or the BAP.
• Parents who have traits of the BAP are more likely than parents who don't have multiple autistic children.
• Families with more than one autistic child are more likely than families with one autistic child to have relatives with the BAP.

Summary

The broad autism phenotype describes a range of autistic traits that do not rise to the level of an official ASD diagnosis. People with BAP may have social, communication, behavioral, sensorial, and relational signs of autism, but not to the extent that requires support.

You may find out that you have BAP traits by speaking with a mental health clinician or your healthcare provider. They may have you take a specific questionnaire to provide further insight.

BAP is considered controversial by some autism advocates. People with level 1 ASD are often able to mask autistic traits in certain settings, which can result in a missed diagnosis. When life pressures increase with age, masking may become more difficult, cause autistic burnout, and lead to a late diagnosis of autism.