Many families of children with autism forgo recommended genetic tests after receiving a diagnosis and that’s a mistake, researchers say.

A new study looking at medical records for 500 kids with autism ages 18 to 36 months finds that when genetic tests do yield a result, that information leads to medical recommendations the vast majority of the time.

The American Academy of Pediatrics and other medical groups recommend two types of genetic testing for all individuals with autism — chromosomal microarray, or CMA, and fragile X testing.

In the study published this week in the journal Pediatrics, 299 of the toddlers — or about 60% — underwent both genetic tests. There were findings in 12% of those cases, with 3% of the children diagnosed with fragile X syndrome and positive results from CMA testing in the others.

Significantly, the genetic findings led to medical recommendations in 72% of the children. Many of the families were informed on how to manage potential seizures while others were referred to specialists in fields including endocrinology, metabolism, sleep issues, ophthalmology and audiology.

This suggests that “genetic findings do not merely provide answers for parents seeking to better understand their child’s diagnosis, but also result in medical recommendations and further monitoring, having a direct impact on the care of our patients with ASD,” said Holly Harris, an assistant professor of pediatrics at Baylor College of Medicine and Texas Children’s Hospital who led the study.

Among those studied, there were no differences in the likelihood that a child would undergo genetic testing based on age, sex, insurance or income. However, kids with physical features related to their condition and those whose parents considered them to be lower functioning were more likely to have the tests.

“But despite those perceptions, we did not find any significant differences in objective measures of developmental functioning or in medical or demographic characteristics between patients with and without positive findings,” Harris said. “This supports the ongoing universal recommendation for genetic testing in ASD regardless of phenotypic characteristics at diagnosis.”

Despite recommendations that everyone with autism receive genetic testing, the tests remain underutilized with a study earlier this year finding that just 3% of those with autism have participated.

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