The Significance of Genetic Testing for Treating Pediatric Diseases
Decoding the molecular interactions between DNA, RNA, and proteins has allowed clinical and laboratory medical professionals to better diagnose and more effectively manage and treat countless medical conditions.
Even though gene sequencing has advanced at an astounding pace since its inception many decades ago, it’s taken years for broad genomic unraveling to reach the clinic.
Microarray assays are tests that identify deletions or duplications of chromosome segments; these duplications are known as copy number variants or CNVs. They’re traditionally the first-tier tests for many clinics when faced with developmental disease (DD) or intellectual diseases (ID). This is because several of the more common DD/ID and autism conditions have deletions and duplications.
Whole genome sequencing and whole exome sequencing can significantly improve and hasten the recognition of genetic risk factors for disease. As a result, it may help get a patient on an effective treatment more quickly.
This type of sequencing can help pinpoint single nucleotide variants (SNVs) or single-point mutations in various genetic conditions, including those that affect the heart and brain. Test results can be particularly useful in the pediatric population, in whom developmental disorders are a major concern and easily identifiable, or in “broad presentation” – when the patient’s clinical presentation is syndromic or could fall under many different diagnoses.
Unfortunately, insurance reimbursement can stand in the way of broad genetic testing in children suspected of having an inherited disorder. Many insurance providers have historically been reluctant to cover whole genome sequencing or exome sequencing since testing for a specific mutation or genetic aberration was cheaper.
Thanks to advances in genomic science, broad genetic testing in children with possible cognitive disabilities may be an easier medical and psychological/emotional journey for pediatric patients and their families.
There is an approach that can help patients and parents shorten their diagnostic journey. One visit to the doctor administering a single broad genetic test could provide all the necessary diagnostic information, taking the place of multiple, more focused genetic tests. The latter process often lasts years before finding a diagnosis.
“Whole-genome sequencing is a single test that could provide a diagnosis,” Hannah Lilligren, Associate Project Manager of PerkinElmer Genomics explains. “Multiple panels and assays could elongate an already arduous diagnostic journey and contribute to more worry, stress, and ineffective clinical management.”
It turns out that wider genome sequencing can save money in the long run.
Guidelines recently issued by the American College of Medical Genetics and Genomics recommended exome and genome sequencing as a first- or second-tier test for patients with congenital anomalies with onset before age 1, or developmental delay or intellectual disability with onset before age 18 years.1
A great many genetic risk factors have been linked with conditions like autism spectrum disorder and pediatric epilepsy, and complete genomic panels are being embraced by professional guidelines at an increasing rate.
Even in the recent past, many neurologic and developmental conditions were thought to be due to a single ‘point’ mutation or to perhaps a few genetic blips that together cause a congenital condition. “But that’s just not the case anymore,” according to Jill Tapper, Product Manager, PerkinElmer Genomics. “These disorders are often more complicated than that, and our technology has come very far,” Tapper explains.
Scientists and doctors are beginning to view conditions like autism differently. More ‘umbrella’ terms that describe a wide range of disorders affected by countless biological, genetic, and environmental risk factors.
“These are disorder spectrums that could be defined phenotypically and genetically in a million different ways,” says Tapper. “And analyzing a whole genome can now help provide a distinct diagnosis in many cases.”
Early intervention can improve learning, communication, social skills, and underlying brain development. It was challenging to get these children the help and resources needed as little as a decade ago. The last ten years have brought many advances in understanding the physical and mental health conditions that frequently accompany autism. Autism is now viewed as a whole-body disorder for many people on the spectrum.2
Ultimately, genomics may improve pediatric medicine by helping doctors and scientists identify children who may benefit from early intervention and care.
Reviewed by Bret Stetka, MD