Beyond the Diagnosis: Evaluation of Quality-of-Life Measures and Family Functioning in SLC6A1 Related Neurodevelopmental Disorder

Aims SLC6A1 related neurodevelopmental disorder (SLC6A1-NDD) is a rare genetic disorder linked to autism spectrum disorder, epilepsy, and developmental delay. In preparation for future clinical trials, understanding how the disorder impacts patients and their families is critically important. Quality of life (QoL) measures capture the overall disease experience of patients. This study presents QOL findings from our SLC6A1-NDD clinical trial readiness study and the Simons Searchlight SLC6A1-NDD registry. Methods We compiled QoL data from participants with SLC6A1-NDD enrolled in our clinical trial readiness study (n=20) and the Simons Searchlight registry (n=32). We assessed the distribution of scores on the Quality-of-Life Inventory-Disability (QI Disability), Quality of Life of Childhood Epilepsy (QOLCE-55), and Pediatric Quality of Life Inventory Family Impact (PedsQL-FIM) administered to caregivers. Results In our cohort of 52 participants, the mean QI Disability total score was 73±12.3, the QOLCE-55 mean total score was 49±17.1, and the mean total PedsQL score was 51±17.6. Longitudinal QoL scores for a subset of participants (n=7) demonstrated a reduction in the Family Relationship domain of PedsQL-FIM (Δ-10.0, p=0.035). Bootstrap resampling of total scores displays non-overlapping 95% confidence intervals for the 10th, 50th, and 90th percentiles on all three measures. Conclusion This is the first study to investigate QoL measures for SLC6A1-NDD. Findings suggest that scores within the 10th percentile’s confidence interval could be clinically significant, referring to QI-Disability scores of <61, QOLCE-55 scores of <46, and PedsQL-FIM scores of <42. Future validation studies are needed.