Personalized Antisense Oligonucleotide Therapy for A Single Participant With ASXL3 Gene Mutation

Incidence and severity of treatment-emergent adverse events (AEs) from baseline to 12- and 24-months post nL-ASXL3-001 administration

Changes from baseline to 12- and 24-months post nL-ASXL3-001 administration in physical examination (changes in appearance, skin, neck, ears, nose, throat, heart/lungs, abdomen, lymph nodes, and extremities compared to baseline)

Changes from baseline to 12- and 24-months post nL-ASXL3-001 administration in neurological examination (changes in mental status, gait, cerebellar, cranial nerve, motor, reflex, and sensations compared to baseline)

Emergent abnormalities in laboratory analyses (results outside of normal range for CSF, chemistry, hematology, coagulation, and urinalysis)

Change in gross motor function from baseline to 12- and 24-months post nL-ASLX3-001 administration as measured by the Vineland Adaptive Behavior Scales - Third Edition (Vineland-3) score.

Change in gross motor function from baseline to 12- and 24-months post nL-ASXL-001 administration as measured by the Gross Motor Function Measure (GMFM 88/66)

Change in feeding tolerance and growth from baseline to 6-, 12-, 18-, and 24-months post nL-ASXL3-001 administration as measured by body mass index (BMI).

Change in feeding tolerance and growth from baseline to 6-, 12-, 18-, and 24-months post nL-ASXL3-001 administration as measured by % oral feeding vs G tube reported by parent feeding diary

Change in feeding tolerance and growth from baseline to 6-, 12-, 18-, and 24-months post nL-ASXL3-001 administration as measured by Functional Oral Intake Score (FOIS)

Change in feeding tolerance and growth from baseline to 6-, 12-, 18-, and 24-months post nL-ASXL3-001 administration as measured by Bristol Stool Scale

Change in communication from baseline to 12- and 24-months post nL-ASXL3-001 administration as measured by Vineland Adaptive Behavior Scales - Third Edition (Vineland-3): growth scale values (GSVs) for Expressive Language and Receptive Language subdomains

Change in cognition, communication, and behavior from baseline to 12- and 24-months post nL-ASXL3-001 administration as measured by Bayley Scales of Infant and Toddler Development 4th Edition (BSID-4): Expressive and Receptive Language Domains and Receptive Language Domains and Cognition Domain

Change in cognition, communication, and behavior from baseline to 12- and 24-months post nL-ASXL3-001 administration as measured by Observer-Related Communication Ability (ORCA) overall T score

Change in cognition, communication, and behavior from baseline to 12- and 24-months post nL-ASXL3-001 administration as measured by Aberrant Behavior Checklist (ABC)

Change in cognition, communication, and behavior from baseline to 12- and 24-months post nL-ASXL3-001 administration as measured by Repetitive Behavior Scale

Change in quality of life from baseline to 6-, 12-, 18-, and 24-months post nL-ASXL3-001 administration as measured by the Quality-of-Life Inventory - Disability (QI-Disability)

Change in swallowing function from baseline to 12- and 24-months post nL-ASXL3-001 administration as measured by video fluoroscopic swallow study (VFSS)

Change in swallowing function from baseline to 12- and 24-months post nL-ASXL3-001 administration as measured by modified barium swallow study (MBSS)

Change in vision from baseline to 12- and 24-months post nL-ASXL3-001 administration as measured by cortical vision impairment assessment

Change in Sleep from baseline to 6-, 12-, 18-, and 24-months post nL-ASXL3-001 administration as measured by parent-reported sleep diary

Change in Sleep from baseline to 6-, 12-, 18-, and 24-months post nL-ASXL3-001 administration as measured by Sleep Disturbances Scale for Children (SDSC)