Interestingly, heterozygous pathogenic variants in NALCN gene are associated, with another disorder predominantly characterized by congenital contractures of the limbs and face, hypotonia, and developmental delay (CLIFAHDD, MIM#616266) that owns a significant phenotypic overlap degree with IHPRF1, but also shows distal arthrogryposis (Chong et al., 2015). This evidence concerns the gene NALCN and Global developmental delay.