Descriptive Study of Individuals with Pitt-Hopkins Syndrome (PTHS)

Background: Limited clinical studies of individuals with PTHS have shown developmental delay and severe intellectual disability, motor difficulties (delayed or not walking), and autistic symptoms (Sweatt, 2013; Van Balkom et al., 2012). PTHS is caused by disruption (mutation or deletion) of transcription factor 4 (TFC4, located on chromosome 18). Haploinsufficiency, or inheriting only one working copy of TCF4 causes PTHS. Approximately, 200-300 documented cases of PTHS exist worldwide.  Though characterized as an ‘atypical’ ASD, individuals with PTHS demonstrate a number of symptoms similar to those diagnosed with autism including: difficulties in pretend play, social interactions, verbal and nonverbal communication; sensitivity to sensory information; and behavioral problems like aggression and tantrums.  The current study focuses on presenting preliminary descriptive information of individuals with PTHS within a well-defined genetic sample.  

Objectives: The purpose of the research is to describe 10 individuals with PTHS living in the US participating in the current study.  Specifically, information on the child’s age, diagnosis/diagnoses, gender, race and ethnicity, loss of skills, intervention and education history, displays of aggression and tantrums, as well as family history of ASD and maternal/paternal education levels will be explored.

Methods: Parents of individuals with PTHS interested in participating completed a comprehensive demographic interview by telephone.  Currently, 26 families have enrolled in the study and preliminary data are presented on the 10 families that have completed the study to date. 

Results:   The study contains 6 males and 4 females who had been diagnosed with PTHS.  The average age of the individuals at the time of their initial demographic interview was 5.85 years with a range of 2.0-17.33 years.  The majority of the participants were Caucasian (90%) and Non-Hispanic/Latino (80%).  In addition to a PTHS diagnosis, many children were also diagnosed with Developmental Delay (80%), Speech Language Disorder (80%), Intellectual Disability (50%), Learning Disability (50%), and Epilepsy (40%).  Only one child was co-diagnosed with ASD.  Only three individuals had a reported loss of language skills at some point during development.  All of the individuals with PTHS were currently receiving speech therapy, occupational therapy, and were either receiving, or had received, Early Intervention services in the past.  Almost all (90%) were receiving physical therapy services. A low frequency of aggression to adults (20%), aggression to peers (30%), and no aggression to strangers were reported.  However, a majority (60%) of individuals were reported to display temper tantrums ranging in frequency from 1 time per day to 2-3 times per week.  Mothers and fathers in the sample were well-educated.  None of the fathers of individuals with PTHS and only one of the mothers reported a family history of ASD.

Conclusions:   Since PTHS is so rare, it is vitally important that researchers and clinicians understand the descriptive information of individuals with this syndrome in more detail in order to differentiate the clinical presentation from that of other developmental disabilities and to guide more informed recommendations for intervention.