MCM3AP and Cognitive impairment: Retrospective analysis revealed different genotype–phenotype correlations for the pathogenic variants in biallelic MCM3AP: all individuals (100%) with mutations outside the Sac3 domain exhibited early-onset symptoms, motor developmental delays, and cognitive abnormalities, conversely, the proportions of individuals carrying mutations within the domain were 26.7% (motor delays) and 46.7% (cognitive abnormalities).