In a new study, UCLA Health researchers have found that motor delay and low muscle tone were common signs of an underlying genetic diagnosis in children with neurodevelopment disorders.

Given the limited existing data on the early neurodevelopmental symptoms that predict a positive genetic diagnosis, the study authors aimed to research which factors in this subset of children indicated the need for a genetic test.

"With genetic testing, a diagnostic result can have benefits on medical care, but we don't have established clinical guidelines on the early neurodevelopmental signs that classify who gets genetic testing or not," said Dr Julian Martinez, study senior co-author and medical geneticist at UCLA Health.

Dr. Martinez said knowing the early neurodevelopment symptoms that signal for a genetic diagnosis can benefit both a patient's family and doctor: a patient's family can advocate seeing a geneticist, and a geneticist provides testing that can potentially give a positive genetic diagnosis, which can help with monitoring the onset of other medical concerns or provide an opportunity to start treatment for the specific genetic condition if one is available.

The study, published in Genetics in Medicine, reviewed medical charts from 316 patients seen at the UCLA Care And Research In NeuroGenetics (CARING) Clinic from 2014 to 2019. The CARING clinic is a multidisciplinary hub where a psychiatrist, geneticist, neurologist, and psychologist collaborate to treat patients with neurodevelopmental disorders.

The patients were categorized based on their genetic testing results, then the researchers documented clinical factors that differentiated patients with and without a genetic diagnosis.

The researchers found that, overall, patients with a genetic diagnosis were more likely to be female and receive early intervention services for a history of motor delay, low muscle tone, and congenital heart disease. Of the study group, 75% of patients with motor delay had a genetic diagnosis, and in patients without motor delay, low muscle tone and age of walking were other indicators for a genetic diagnosis.

"For many years, the genetics field has diligently worked on figuring out who are the patients that would benefit the most from genetic testing," Martinez said. "So, it's helpful to know that a delay in motor skills yields a very high likelihood of a genetic diagnosis."

"This study takes us a step closer to developing evidence-based guidelines for genetic testing in neurodevelopmental disorders," said Dr. Aaron Besterman, study senior author and former UCLA Health Postdoctoral Researcher who's now a health sciences associate clinical professor at the UCSD Department of Psychiatry.

"By identifying key clinical features, we can help ensure that the children most likely to benefit from genetic testing receive it promptly."

Dr. Martinez said that an early genetic diagnosis can lead to managing or anticipating a medical co-occurrence such as congenital heart disease, a psychiatric illness, or information on a higher likelihood of experiencing seizures. He also said while controversial, some families prefer to be informed about their genes for family planning.

"With the use of genetic evaluations and precision medicine, the intent is to shorten the diagnostic odyssey—meaning the long period of time it takes for a patient to receive a diagnosis—so that we can nurture the patient and provide the personalized care that is best specifically for the patient with a unique diagnosis and not necessarily treat them like anybody else."