The neurodevelopmental phenotype characterizing patients carrying heterozygous CTNNB1 variants was further delineated by Tucci et al. in 2014 [2], who observed that CTNNB1 syndrome (OMIM #116806) is mainly characterized by developmental delay and intellectual disability (ID) (IQ < 70), and autism spectrum disorder. This evidence concerns the gene CTNNB1 and Down syndrome.