A Natural History of NAA15-related Neurodevelopmental Disorder Through Adolescence.

NAA15 is a member of the NatA N-terminal acetyltransferase complex which acts by interacting with the NAA10 enzymatic sub-unit. Individuals with variants in the NAA15 coding region develop NAA15-related neurodevelopmental syndrome which presents with a wide array of manifestations that affect the heart, brain, musculoskeletal system, and behavioral and cognitive development. We tracked a cohort of 26 participants (8 females and 18 males) over time, each with a pathogenic NAA15 variant, and administered the Vineland-3 assessment to them to assess their adaptive functioning. We found that the cohort performed significantly worse compared to the normalized Vineland values. On average, females performed better than males across all domains. They performed significantly better on the Motor Domain and Fine Motor Sub-Domain portions of the assessment. Over time, females showed a decrease in adaptive functioning with the decline being especially strongly correlated at the Coping subdomain, Domestic sub-domain, and Fine motor sub-domains. It is difficult to determine the strength of these correlations due to limited power. Males (after excluding one outlier) showed a moderate positive correlation between age and ABC standard score. Ultimately, additional longitudinal data should be collected to determine the validity of the between sex-differences and to better understand the change in adaptive behavioral outcomes of individuals with NAA15-neurodevelopmental disorder as they age.