Given that the contiguous gene deletion syndrome of 9q22.3 has a similar phenotype to NBCCS, but also includes intellectual disability, it is plausible that whole gene deletion may lead to a more severe phenotype than single nucleotide variants or small deletions and duplications within PTCH1, thereby providing a possible explanation for the discrepant findings in the rate of intellectual disability these populations27,28. Here, PTCH1 is linked to Intellectual disability.