Sensorimotor Behavior in Individuals With Autism Spectrum Disorder and Their Unaffected Biological Parents

Sensorimotor impairments are common in autism spectrum disorder (ASD) and evident in unaffected first-degree relatives, suggesting that they may serve as endophenotypes associated with inherited autism likelihood. We tested the familiality of sensorimotor impairments in autism across multiple motor behaviors and effector systems and in relation to parental broader autism phenotypic (BAP) characteristics. Fifty-seven autistic individuals (probands), 109 parents, and 89 neurotypical control participants completed tests of manual motor and oculomotor control. Sensorimotor tests varied in their involvement of rapid, feedforward control and sustained, sensory feedback control processes. Subgroup analyses compared families with at least one parent showing BAP traits (BAP+) and those in which neither parent showed BAP traits (BAP−). Results show that probands with BAP− parents (BAP− probands) showed atypical control of rapid oculomotor behaviors, while BAP+ probands showed impairments of sustained manual motor and oculomotor behaviors compared to controls. BAP− parents showed impaired rapid oculomotor and sustained manual motor abilities relative to BAP+ parents and controls. Rapid oculomotor behaviors were highly intercorrelated among probands and their biological parents. These findings indicate that rapid oculomotor behaviors are selectively impacted in BAP− probands and their parents and may reflect a familial likelihood for autism independent of parental autistic traits. In contrast, sustained sensorimotor behaviors were affected in BAP+ probands and BAP− parents, suggesting separate familial pathways associated with autism. Finally, atypical saccade dynamics may serve as strong endophenotypes for autism. These findings provide new evidence that rapid and sustained sensorimotor alterations represent strong but separate familial pathways of inherited likelihood for autism.