Onset Patterns in ASD: Early Development, Later Outcomes and the Association with Mitochondrial Dysfunctions.

Poster Presentation
Friday, May 11, 2018: 11:30 AM-1:30 PM
Hall Grote Zaal (de Doelen ICC Rotterdam)
S. Boterberg1, E. Vantroys2, R. Siugzdaite3, R. Van Coster4 and H. Roeyers1, (1)Department of Experimental-Clinical and Health Psychology, Ghent University, Ghent, Belgium, (2)Department of Pediatric Neurology and Metabolism, Ghent University Hospital, Gent, Belgium, (3)Department of Experimental Psychology, University of Ghent, Ghent, Belgium, (4)Department of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
Background: Behavioral signs of ASD emerge through different patterns: early onset, regression and plateau. Regression is assumed to be characterized by a ‘typical’ development, followed by a loss of previously acquired skills at a mean age of 21 months in 33% of the children with ASD. Recently, a meta-analysis on mitochondrial dysfunctions (MD) in ASD demonstrated an overall prevalence of 5%. Children with ASD+MD showed more seizures, motor delay, gastro-intestinal abnormalities and an elevated lactate (a biochemical marker of MD). Furthermore, in 52% of the cases, regression was noted.
More insight into the course, prevalence and pathogenesis of onset patterns in ASD would be of significant diagnostic and clinical value.

Objectives: The first purpose is to explore the trajectories of onset patterns in ASD and long-term outcomes. Second, we want to examine the presence of MD and their association with the severity of ASD-symptoms and regression.

Methods: Participants were 100 children with ASD (M age=7.48y,sd=1.98,range=3-11y;70% boys). Parent report was used to measure early ASD-symptoms and classification to onset group (EDQ,ADI-R,RSQ). Non-verbal intelligence was measured through the WNV and current severity of ASD-symptoms by the ADOS-2. Screening of MD included measurement of lactate in urine and near-infrared spectroscopy (fNIRS) in the brain.

Results: The results revealed an early onset (≤12m;38%), a later onset (>12m;34%) and an early onset+regression group (10%). Other children had a typical development followed by regression (13%) or plateau (5%). Regression (M onset=22m) involved in 78% of the children loss of language skills. Children with regression (ASD-R) showed significantly lower non-verbal intelligence scores (M IQ=81.50,sd=21.47) compared to children without regression (ASD-NR;MIQ=93.04,sd=20.18;t(94)=2.321,p<.05). Examination of current severity of ASD-symptoms showed significantly more symptoms in ASD-R (U(98)=1152.5,p<.05).
Based on the lactate results, the children were divided into three groups: low lactate (n= 20;M=2.05mg/dL,sd=.84), medium lactate (n=58;M=5.45mg/dL,sd=1.75) and high lactate (n=20;M=11.52mg/dL,sd=2.55). Examination of early and current severity of ASD-symptoms showed no significant differences between the two extreme groups. Furthermore, no significant differences in non-verbal intelligence were found between the low (M IQ=87.37,sd=24.60) and the high lactate group (M IQ=90.75,sd=23.40; t(37)=.441;p=.662). The proportion of ASD-R did not differ between the high and the low lactate group (χ²(1)=3.135;p=.08). In addition, there was no significant difference between the lactate value of ASD-R (M=5.27mg/dL,sd=2.93) compared to ASD-NR (M=6.23mg/dL,sd=3.77;U(98)=757.5,p=.281). However, preliminary fNIRS results showed a significant difference between ASD-R and ASD-NR in the curves of the oxy-hemoglobin response in the temporal lobe of the right hemisphere (z=3.215;p<.05).

Conclusions: We found support for different onset patterns previously suggested in the literature. Further, ASD-R display more severe impairments later in life as measured by non-verbal IQ and ASD-symptomatology.
Based on lactate in urine as a biochemical marker of MD, no significant differences in the severity of ASD-symptoms and onset patterns were found. Still, there is a need for further examination since normal lactate levels have been reported in case studies of ASD+MD. Furthermore, preliminary analysis of fNIRS data showed a higher oxy-hemoglobin level in the brain of ASD-R. Final fNIRS results will be presented at the conference.