Clinical actionability of genetic findings in cerebral palsy

Background and objectivesSingle gene mutations are increasingly recognized as causes of cerebral palsy (CP) phenotypes, yet there is currently no standardized framework for measuring their clinical impact. We evaluated Pathogenic/Likely Pathogenic (P/LP) variants identified in individuals with CP to determine how frequently genetic testing results would prompt changes in care. MethodsWe analyzed published P/LP variants in OMIM genes identified in clinical (n = 1,345 individuals) or research (n = 496) cohorts using exome sequencing of CP patients. We established a working group of clinical and research geneticists, developmental pediatricians, genetic counselors, and neurologists and performed a systematic review of existing literature for evidence of clinical management approaches linked to genetic disorders. Scoring rubrics were adapted, and a modified Delphi approach was used to build consensus and establish the anticipated impact on patient care. Overall clinical utility was calculated from metrics assessing outcome severity if left untreated, safety/practicality of the intervention, and anticipated intervention efficacy. ResultsWe found 140/1,841 (8%) of individuals in published CP cohorts had a genetic diagnosis classified as actionable, defined as prompting a change in clinical management based on knowledge related to the genetic etiology. 58/243 genes with P/LP variants were classified as actionable; 16 had treatment options targeting the primary disease mechanism, 16 had specific prevention strategies, and 26 had specific symptom management recommendations. The level of evidence was also graded according to ClinGen criteria; 44.6% of interventions had evidence class "D" or below. The potential interventions have clinical utility with 97% of outcomes being moderate-high severity if left untreated and 62% of interventions predicted to be of moderate-high efficacy. Most interventions (71%) were considered moderate-high safety/practicality. DiscussionOur findings indicate that actionable genetic findings occur in 8% of individuals referred for genetic testing with CP. Evaluation of potential efficacy, outcome severity, and intervention safety/practicality indicates moderate-high clinical utility of these genetic findings. Thus, genetic sequencing to identify these individuals for precision medicine interventions could improve outcomes and provide clinical benefit to individuals with CP. The relatively limited evidence base for most interventions underscores the need for additional research.