Neurobehavioral phenotype of autism spectrum disorder associated with germline heterozygous mutations in PTEN

Abstract

Germline mutations in PTEN, the gene that encodes phosphatase and tensin homolog, have been identified in up to 20% of children with autism spectrum disorder (ASD) and macrocephaly and are associated with marked abnormalities in the white matter of the brain. This study sought to characterize the neurobehavioral phenotype of PTEN-ASD. Comprehensive neurobehavioral evaluations were conducted in 36 participants (ages 3-21 years) with PTEN-ASD and compared to two groups of controls: non-syndromic ASD with macrocephaly (Macro-ASD, n = 25) and those with PTEN mutations without ASD (PTEN-no ASD, n = 23). Linear regression analysis or Kruskal-Wallis tests were used to examine group differences on neurobehavioral measures (cognitive, behavioral, sensory, and adaptive functioning) and, for select measures, one-sample t-tests were used to compare group performance to healthy control norms. These analyses revealed a distinct neuropsychological profile associated with mutations in PTEN suggesting primary disruption of frontal lobe systems (i.e., attention, impulsivity, reaction time, processing speed, and motor coordination). Cognitive deficits in PTEN-ASD are more severe than those in PTEN-no ASD and extend to other areas of neurobehavioral function, specifically, adaptive behavior and sensory deficits. While core ASD symptoms are similar in PTEN-ASD and Macro-ASD, PTEN-ASD had lower clinical ratings of autism severity and showed more sensory abnormalities suggestive of less sensory responsiveness. Together, these results suggest that PTEN-ASD has a distinct neurobehavioral phenotype compared to idiopathic ASD that is likely to warrant special consideration for overall assessment and treatment.

Fig. 1. Group differences in cognitive and motor functioning.

Higher scores indicate better cognitive performance for all domains, except attention, impulsivity, and reaction time. Full Scale IQ and processing speed are reported on a standard score scale (M = 100, SD = 15), attention, impulsivity, and reaction time are reported on a t-score scale (M = 50, SD = 10), and motor is reported as a raw score. The measures used to assess the noted cognitive domains are outlined in Supplementary Table 1. ASD, autism spectrum disorder

Fig. 2. Group differences in sensory functioning.

Higher scores indicate fewer sensory difficulties. Typical performance score ranges: Tactile Sensitivity 30–35, taste/smell sensitivity 15–20, under responsive/seeks sensation 27–35, low energy/weak 26–30. SSP, short sensory profile, ASD, autism spectrum disorder

Fig. 3. Cognitive performance in PTEN-ASD compared to healthy control norms.

Upgoing bars indicate performances higher than normative mean z-score of 0, and downgoing bars indicate performances lower than normative mean z-score of 0. BRIEF, Behavior Rating Inventory of Executive Function, DCDQ, Developmental Coordination Disorder Questionnaire, VABS, Vineland Adaptive Behavior Scale, ASD, autism spectrum disorder