TCF4 and Pitt-Hopkins syndrome: The list of TCF4 mutations found in the hundreds of patients with PTHS described so far include missense (~15% of cases), nonsense (~15%), and splice-site (~10%) point mutations, as well as small insertions or deletions (indels) resulting in frameshift (~30%), and translocations and large deletions encompassing TCF4 partially or entirely (~30%)23,41,43–46.