Implications of Provider Specialty, Test Type, and Demographic Factors on Genetic Testing Outcomes for Patients with Autism Spectrum Disorder.

This study looked at genetic testing for autism over 6 years. It found that different doctors order different types of genetic tests, with specialists more likely to order comprehensive tests that find genetic causes. The most thorough test (exome sequencing) found genetic causes in about 1 in 4 children tested. Girls were slightly more likely than boys to have a genetic cause found for their autism. The study suggests many children aren't getting the best genetic tests available.

This retrospective study analyzed genetic testing patterns for autism spectrum disorder (ASD) from a large clinical laboratory over 6 years (2017-2022). Geneticists and neurologists were more likely to order comprehensive tests like exome sequencing and neurodevelopmental panels, while other providers typically ordered chromosomal microarray and Fragile X testing. Exome sequencing showed the highest diagnostic yield at 24.5%, significantly outperforming other test types. Females were 1.4 times more likely than males to receive a genetic diagnosis overall, though males had higher diagnostic yield for Fragile X specifically.

The findings suggest current genetic testing practices may be suboptimal, with many providers not ordering the most diagnostically useful tests.

Results suggest need for improved genetic testing protocols for ASD, with exome sequencing as first-tier testing. Non-genetics providers may benefit from education on comprehensive genetic testing options or clearer referral pathways to genetics specialists following negative initial testing.

Retrospective design limits causal inferences. Sample size not reported. Study limited to one laboratory's data, potentially affecting generalizability. Patient selection criteria and clinical characteristics not fully described.

A minority of patients with autism spectrum disorder (ASD) are offered genetic testing by their providers or referred for genetics evaluation despite published guidelines and consensus statements supporting genetics-informed care for this population. This study aimed to investigate the ordering habits of providers of different specialties and to additionally assess the diagnostic utility of genetic testing by test type, patient sex, and race and ethnicity. We retrospectively analyzed data associated with orders for the indication of ASD from a large clinical laboratory over 6 years (2017-2022). Geneticists and neurologists were more likely than other specialists to order exome sequencing and neurodevelopmental (NDD) panel testing while other providers were more likely to order chromosomal microarray (CMA) and Fragile X testing.

Exome had the highest diagnostic yield (24.5%), followed by NDD panel (6.4%), CMA (6.2%), and Fragile X testing (0.4%). Females were 1.4x (95% CI: 1.2-1.7) more likely than males to receive a genetic diagnosis. However, for Fragile X, males had a higher diagnostic yield than females (0.4% vs 0.2%). Our findings highlight the need to enable non-genetics providers to order comprehensive genetic testing or promote referral to genetics following negative CMA and/or Fragile X testing.

Our data supports that ASD testing should include exome, CMA, and other clinically indicated tests, as first-tier tests, with the consideration of panel testing, in cases where exome sequencing is not an option. Lastly, our study helps to inform expectations for genetic testing yield by test type and patient presentation.