Is Sensory Responsiveness an Endophenotype of Autism Spectrum Disorders?

Background:  For children with autism spectrum disorders (ASD), atypical sensory responsiveness has been shown to be much more common than among children unaffected with ASD.  Although numerous studies have examined the social abilities of siblings of children with ASD, few have examined their sensory characteristics.  An aggregation of sub clinical autistic social impairment traits and complex immune dysfunction have been found in unaffected family members of children with ASD, suggesting that such impairments constitute autism endophenotypes (traits that are associated with a diagnosis, are heritable, and manifest in family members with or without the diagnosis).  It is important to determine if patterns of atypical sensory processing occur in unaffected members of ASD families to better understand the heritability of this trait and the vulnerability of siblings for sensory responsiveness issues. 

Objectives:  This study examined the sensory responsiveness of children with ASD and controls, including sibling pairs in children from families with ASD, to better understand the heritability of atypical sensory responsiveness in families with ASD.  In addition, differences in sensory responsiveness patterns were examined across ages from 4 to 17.99 years in children with and without an ASD diagnosis.

Methods: Sensory Profile Caregiver Questionnaires (SPCQ; for < age 11) or Adolescent and Adult Sensory Profile Questionnaires (AASP; for age 11+) were completed by parents of 253 children between age 4 and 17.99 (158 ASD, 54 unaffected siblings and 41 controls; 209 white, 42 black, 2 Asian).  Common sensory responsiveness items for the four sensory quadrants (overall patterns of responses: low registration, sensation seeking, sensory sensitivity, sensation avoiding) and five sensory domains (responses to specific types of sensory input: auditory, visual, touch, vestibular, taste/smell) were analyzed.  Use of the common items allowed for inclusion of participants from both Sensory Profile age categories and raw quadrant and domain scores were compared between probands, affected siblings, unaffected siblings and controls. Common item scores were also compared across ages for affected and unaffected children.

Results:   Significant differences were seen in scores between children with ASD and their unaffected siblings for all sensory domains and quadrants.  Significant differences were seen in scores for the vestibular domain (p=.02) and the sensation avoiding quadrant (p=.008) between unaffected controls and unaffected siblings. No differences were seen between Caucasian and African American children.

Patterns of significantly more typical responses were seen in unaffected children as their ages increased from 4 to 17.99 years in three of the four quadrants.  For the children with ASD, close to significance was seen as the ages of the children increased in two of the four quadrants.  Scores showed similar patterns of significantly more typical responses in unaffected children but not in the children with ASD in visual, vestibular, auditory and gustatory/olfactory, but not tactile domains with increased age. 

Conclusions:  Findings suggest that some degree of heritability in the sensory responsiveness is present among siblings from the families affected with ASD. In addition, trends toward more typical sensory responsiveness are generally seen in older typically developing children, but rarely in children with ASD.