Expression of the broad autism phenotype in simplex autism families from the Simons Simplex Collection.
In simplex autism families, different BAP checklists give different answers, so low reported rates may say more about the tool than the family.
01Research in Context
What this study did
The team looked at parents in simplex autism families. These are families with only one child on the spectrum.
They gave three different pencil-and-paper checklists to each parent. Each checklist claims to measure the broad autism phenotype, or BAP.
The goal was to see if the three tools pick out the same parents as having BAP traits.
What they found
Only a small slice of parents scored high on any measure. The exact count changed depending on which form the researchers used.
Agreement between the three tools was weak. A parent could look “BAP-positive” on one form and typical on another.
Because the numbers shift with the measure, the study calls the true rate of BAP in simplex families “inconclusive.”
How this fits with other research
Fahmie et al. (2013) used the same Simons Simplex families one year earlier. They also found fewer BAP traits in simplex than in multiplex relatives, so the low numbers are not a fluke.
Emerson et al. (2007) created the Broad Autism Phenotype Questionnaire, one of the three tools tested here. Their early work showed the BAPQ works in other groups; Julie et al. now warn it may still miss some simplex parents.
Muller et al. (2022) add another twist. They showed that parents who do have BAP traits tend to over-rate autism symptoms in their kids. This means measure choice can echo downstream and color teacher reports as well.
Cox et al. (2015) reacted to this mess by building new interview-based measures. Their goal was to tighten agreement after Julie et al. showed the old surveys disagreed.
Why it matters
If you screen parents for research or parent-training studies, pick one tool and stick with it. Switching mid-study can change who looks “affected.” When you read genetics papers, check which questionnaire they used; low BAP rates in simplex families may be tool-driven, not biology-driven. For clinical work, remember that a “negative” screen on one form does not rule out BAP traits—use multiple sources if the family history matters for intervention planning.
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02At a glance
03Original abstract
The broad autism phenotype (BAP) refers to the phenotypic expression of an underlying genetic liability to autism, manifest in non-autistic relatives. This study examined the relationship among the Broad Autism Phenotype Questionnaire (BAPQ), Social Responsiveness Scale: Adult Research Version (SRS:ARV), and Family History Interview (FHI) in a large, multi-site study of 1,650 simplex families (Simons Simplex Collection). Correlations between the BAPQ and SRS:ARV Total scores were moderate, and correlations between FHI ratings and SRS:ARV and BAPQ were significant but weak. Overall, the results suggested that BAP traits occur at low rates in simplex families, and rates vary significantly depending upon the measure utilized. Implications include the need for multiple informants, and the assessment of distinct BAP traits in large-scale genetic studies of individuals with ASD.
Journal of autism and developmental disorders, 2014 · doi:10.1007/s10803-012-1492-1