Previously in humans, pathogenic SOX4 variants encompassing causative missense and truncating variants were involved in the etiopathogenesis of Coffin–Siris syndrome, a rare genetic disease characterized by multi-systemic developmental anomalies with a phenotypic spectrum varying from mild cognitive delays to intellectual disabilities with various congenital deformities, including craniofacial dysmorphism, hypoplasia or absence of the fifth distal phalanges/nails, and dental abnormalities [87,104]. This evidence concerns the gene SOX4 and Coffin-Siris syndrome.