Almost all of the individuals with variants in NAA10 appear to involve a change of one amino acid in the protein to another amino acid, which is referred to as a missense variant. The most common such change is Arginine 83 Cysteine, which has been observed in several dozen females at this point. At least one male boy was born with this same change, but he died in infancy, with cardiac arrhythmias. There are however, at least two brothers in Ireland, with a different missense variant, and they have survived to adulthood, although they did require cardiac interventions. The most notable feature of the syndrome is the marked variability, with some children having severe feeding difficulties and severe developmental delay, while other children have more mild presentations. In females, this may be correlated with a process called X-chromosome inactivation, as the amount of normal protein expressed from the normal chromosome in females can be variable.
NAA10