Pitt Hopkins Syndrome (PTHS) is a rare genetic disorder affecting a specific gene in chromosome 18, called TCF4. PTHS is characterized by intellectual disability and developmental delay which range from moderate to severe, possible breathing problems of episodic hyperventilation and/or breath-holding while awake (55%-60%), recurrent seizures/epilepsy (40%-50%), gastrointestinal issues, and distinctive facial features. Children with Pitt-Hopkins syndrome typically have a happy, excitable demeanor with frequent smiling and laughter. PTHS was first described by D. Pitt and I. Hopkins in the Australian Pediatric Journal in 1978. The connection to TCF4 was not established until 2007 when it was found to play an essential role in the development of the nervous system and the brain. Any functional deficiency of TCF4 greatly affects how a child develops over time.
Overall prevalence of PTHS is unknown. However, one laboratory estimated that the frequency of chromosome 18q21 deletions associated with PTHS is between 1 in 34,000 and 1 in 41,000. An estimate from another researcher is 1 in 200,000-300,000. Researchers will need recognize individuals with PTHS in all age groups first and molecular analyses should be more widely available too, before this estimate is more accurate. A blood test needs to be around for about 10 years or so to get a better picture of incidence and it is only half way through this period at this time. PTHS occurs in both males and females and is not limited to a specific ethnic background.
A Changing Perspective
In the recent past, it was believed that all children affected by PTHS would suffer from severe to profound overall disability, unable to walk, speak, or relate to others. All hope was taken away from parents who received a PTHS diagnosis for their children.It’s amazing how this perspective has changed over the last few years. Families from the US and Europe, each with a newly diagnosed child with PTHS, created a Google support group in 2008. This international group now gathers over 225 families worldwide, with a new family joining almost every week! We have found through this support group that the accessible medical literature can be not only impersonal and misleading but often inaccurate in many ways, because much of the research is based on a few severe cases that don’t take into account variability in individual children. In contrast, the collective knowledge obtained by our support group and recent research efforts are showing that PTHS children are creative, vibrant, and joyful people continuing to learn over time, and who seem to bring happiness to everyone who knows them. This is truly a message of hope that we aspire to spread around the world.
For more detailed information, please also see the following National Institutes of Health Gene Reviews article on Pitt Hopkins Syndrome: http://www.ncbi.nlm.nih.gov/books/NBK100240/