PAK1 and Macrocephaly: The PAK1 (OMIM: 602590) gene located in 11q13.5q14.1 region is highly expressed during embryogenesis and in adult tissues including the brain, muscle, and spleen [5]. In the recent reports, de novo PAK1 variants were described to be causative of neurodevelopmental disorder with macrocephaly, seizures, and speech delay [6].