Due to the limited number of studies in this area and to better understand the role of the pathogenic PAK1 gene variant described in this study in Intellectual Developmental Disorder with Macrocephaly, Seizures, and Speech Delay (IDDMSSD), we aimed to present below the physiological role of PAK1 kinase in the organism, as well as to discuss the pathogenic variants occurring within the two domains of this protein, the autoinhibitory domain and the kinase domain, in the context of pathogenesis. This evidence concerns the gene PAK1 and Delayed speech and language development.