Demographic and Clinical Characterization of Participants in the Australian Autism Biobank

Background: The clinical and genetic heterogeneity within individuals diagnosed with Autism Spectrum Disorder (ASD) represents significant challenges to advancing knowledge about etiological pathways and clinical outcomes. Considerable progress in this area has been made through collaborative and large-scale projects, necessitating a similarly large resource to be established in Australia, a country with unique ethnic and cultural diversity. Established in 2014, the Australian Autism Biobank was initiated by the Cooperative Research Centre for Living with Autism (Autism CRC).

Objectives: To summarise the clinical and demographic features of participants recruited to participate in the Australian Autism Biobank.

Methods: Participants recruited were children with a diagnosis of ASD, aged between 2-17 years, at four data collection sites across Australia. Biological parents and siblings, both with and without ASD, were also invited to participate, as well as non-autistic children (‘controls’) recruited from the general community. A smaller group of children presenting to recruitment sites clinically referred for an ASD diagnostic evaluation but who did not meet diagnostic criteria were also invited to participate (‘ASD-query’). No exclusion criteria regarding language level, cognitive ability, or comorbid medical, psychiatric or genetic condition was applied to children diagnosed with ASD. All children completed cognitive or developmental assessments, with probands and ASD-query children additionally completing ASD assessments. Parents/caregivers completed questionnaires about medical and developmental history. Physical measurements as well as blood, stool, urine, and hair samples were collected from children; physical measurements and blood samples were collected from both parents of probands.

Results: A total of 979 probands (first child in family diagnosed with ASD) participated (20.4% females, 83.4% Caucasian, 12.9% Asian, 1.7% Aboriginal, 2.0% Maori or Pacific Islander), with an average age of 7.4±3.9 years (mean±SD) at assessment. 173 autistic siblings were also recruited (7.8±3.5 years, 30.1% females), comprising 145 multiplex families (between 2-5 children diagnosed) and 27 twin pairs. 847 mothers (39.5±6.4 years, range 22-68 years), 548 fathers (42.1±7.5 years, range 19-82 years) and 263 non-autistic siblings (8.2±4.2 years, range 2-16, 51% females) also participated. 150 non-autistic controls (6.2±3.4 years, 2-15 years, 51% female) and 16 ASD-query children (6.1±2.6, 3-10 years, 50% female) were also included in the cohort. Within the proband group, age at diagnosis ranged from 12-211 months (55.7±34.7) and IQ scores ranged from 40-138 (79.5±23.3). Based on parent/caregiver reports, 31.4% of probands had a diagnosed Intellectual Disability or Global Developmental Delay (n = 311), 4.5% had epilepsy (n = 45), and 2.2% had a previously diagnosed genetic condition (n = 22).

Conclusions: This initiative has resulted in a valuable and detailed resource comprising clinical information alongside biological samples to help increase our understanding of the underlying mechanisms associated with an ASD diagnosis. Both phenotypic and biological data are now available for access requests from the research community.