3.5 Syndromes similar to Pitt Hopkins
3.5 Overlapping phenotypes
Sometimes, people look and behave a lot like people with Pitt Hopkins syndrome, but don't quite qualify for a Pitt Hopkins diagnosis. When their DNA is checked, no changes in the part coding for Transcription Factor 4 is found. Some of these have Pitt-Hopkins-like syndromes I and II. A number of people were suspected to have Pitt Hopkins, but when no mutation in TCF-4 was found, the scientists checked their characteristics again and decided they did not actually have all the clinical diagnostic criteria necessary for the Pitt Hopkins diagnosis.40,41
When it looks like someone has Pitt Hopkins syndrome, but no change in the DNA coding for TCF-4 is found, other syndromes should be considered. For instance, they may have Angelman syndrome, Kleefstra syndrome or Mowat-Wilson syndrome, or a number of other syndromes. Because the way these people look, act and develop overlaps with Pitt Hopkins, scientists talk about 'overlapping phenotypes'.