The X-linked lethal Ogden syndrome was the first reported human genetic disorder associated with a mutation in an N-terminal acetyltransferase gene. The affected males harbour a Ser37Pro mutation in the gene encoding hNaa10, the catalytic subunit of NatA, themajor human NAT. In order to understand the detrimental impact of hNaa10 Ser37Pro, we performed structural, molecular and cellular investigations. Structural models and molecular dynamics simulations of the human NatA and its Ser37Pro mutant suggest differences in regions involved in catalysis and at the interface between hNaa10 and the auxiliary subunit hNaa15. In agreement, biochemical data demonstrate a reduced catalytic capacity and an impaired NatA complex formation with hNaa10 Ser37Pro. Patient derived Naa10 mutant cells show reduced Nt-acetylation for a subset of NatA/NatE-type substrates compared to wild type Naa10 cells. Ogden syndrome fibroblasts further display abnormal cell proliferation and migration capacity, possibly linked to perturbed Retinoblastoma- and MYLK-pathways, respectively. Differential N-terminal combined fractional diagonal chromatography (COFRADIC) was used to quantify the degree and define the patterns of in vivo protein Nt-acetylation and here used to investigate whether patient cells derived from an affected Ogden male (carrying the Naa10 S37P mutation) displayed altered levels of protein Nt-acetylation at the proteome-wide level.