Pitt-Hopkins Syndrome, which is present at birth or develops in early childhood, is caused by mutations in the TCF4 gene located on chromosome 18q21.2. There are reportedly only 500 cases of the syndrome in the world though it is thought the syndrome may be underdiagnosed. One of the major reasons for this likely underdiagnosis is the syndrome has many characteristics that are also associated with autism spectrum disorders; although there are other distinctive features of the syndrome as well.
Like autism spectrum disorders, many of those with Pitt-Hopkins Syndrome have delayed development of mental and motor skills. People with the syndrome typically do not develop speech or learn only a few words. Delays often occur in learning to walk. Additionally, their demeanor is “typically … happy, excitable…with frequent smiling, laughter and hand-flapping movements.” Those with the syndrome commonly experience “anxiety and behavioral problems;” and they may also experience recurrent seizures.
Some unique features of Pitt-Hopkins Syndrome are breathing problems and certain facial and ear characteristics. The breathing problems can fluctuate between hyperventilation and slowed breathing or even apnea and may be triggered by “fatigue, anxiety or excitement.” The distinctive facial features are “thin eyebrows, sunken eyes, a prominent nose with a high nasal bridge, a pronounced double curve of the upper lip called Cupid’s bow, wide mouth with full lips and widely spaced teeth.” Additionally, the ears may be “thick and cup-shaped.”
A recent gene research breakthrough that may lead to a treatment for Pitt-Hopkins Syndrome was discovered by scientists at the Johns Hopkins University-affiliated independent laboratory, the Lieber Institute for Brain Development. The researchers studied the brains of rats affected by Pitt-Hopkins Syndrome and found “alternative channels in the brain interrupting normal cell activity.” The gene research showed these interruptions caused inappropriate responses to stimuli in the environment. Further, the researchers discovered a drug being “investigated for use on chronic pain” that blocked these alternative channels resulting in cells behaving normally. However, at this point, researchers are not sure what restoring normal cell activity would do to those with the syndrome but are hopeful that some of the deficits could be eliminated.
Sources: CapitalGazette.com of March 11, 2016.
Ghr.nlm.nih.gov; “Pitt-Hopkins Syndrome;” Last reviewed February 2015.