Quantifying neurobehavioral profiles across neurodevelopmental genetic syndromes and idiopathic neurodevelopmental disorders

Aim: To examine neurobehavioral findings in three genetic syndromes (PTEN hamartoma tumor syndrome, Malan syndrome [mutations in the NFIX gene], and SYNGAP1-related disorder), a mixed group of other neurodevelopmental genetic syndromes (NDGS), idiopathic neurodevelopmental disorder, and neurotypical control participants. Method: Using a longitudinal case–control design, caregivers reported neurobehavioral information for 498 participants (PTEN hamartoma tumor syndrome n = 112, Malan syndrome n = 24, SYNGAP1-related disorder n = 47, other NDGS n = 72, idiopathic neurodevelopmental disorder n = 54, neurotypical siblings n = 74, and unrelated neurotypical control participants n = 115) at three timepoints (baseline, and 1-month and 4-month follow-ups) using the online-administered Neurobehavioral Evaluation Tool (NET). Results: NET scales had good scale and test–retest reliability. Unique patterns of neurobehavioral findings emerged, with SYNGAP1-related disorder and Malan syndrome showing generally more severe symptom and skill patterns than for other groups of patients. Patterns could be partly accounted for by estimated cognitive level, speech level, and the presence of autism spectrum disorder. However, even when accounting for these factors, group differences remained. Reliable change indices are reported. Interpretation: Genetic syndromes associated with neurodevelopmental disorders present with unique neurobehavioral profiles that can inform selection of outcome measures in future clinical trials. The NET may be a useful screening and monitoring instrument in clinical practice, where frequent in-person clinic attendance is difficult for many patients.