Genetic diagnostic outcomes from a 10-year research programme in autism in Aotearoa New Zealand

Autism is a relatively common neurodevelopmental difference with considerable phenotypic heterogeneity impacting cognitive, sensory, and social processing, and often co-occurs with other conditions. Therefore, there is not a one-size-fits-all clinical support pathway for autistic individuals following diagnosis. DNA sequencing technology has enabled the discovery of genes causative of, or associated with, autism. Unsurprisingly, genetic heterogeneity goes hand-in-hand with the phenotypic heterogeneity for this condition; with causative genetic variation ranging from single base pair changes to complex chromosomal rearrangements in more than 100 different genes. This study captures a snapshot (201 individuals) of the autistic population (both clinically referred and self-referred) in Aotearoa New Zealand and documents a decade’s research effort to refine diagnosis using a flexible and customised genome-wide sequencing approach. The diagnostic yield in this phenotypically disparate cohort was 12.9%, with an additional 15.9% of individuals harbouring ‘likely causal’ variants, providing the groundwork to tailor clinical, social, and educational care. Importantly, this study reveals the diagnostic utility of customised genetic screening for autism across a phenotypically diverse autistic population.