Prevalence of poisoning in people with Prader-Willi syndrome

Ulrika S. Lange¹, Karen Potter², and Shawn E. McCandless³

¹University of North Carolina at Greensboro, Genetic Counseling Program, Greensboro, NC; ²Department of Pediatrics, Division of Genetics and Metabolism, University of North Carolina, Chapel Hill, NC; ³Departments of Genetics and Pediatrics, Case Western Reserve University, Cleveland, OH 

This pilot study assessed the prevalence of poisoning in people with Prader-Willi syndrome (PWS).  Hyperphagia and unusual food-seeking behaviors are key features of PWS and lead to ingestion of unappetizing and unappealing foods such as garbage or pet food.  The main goal of this study was to examine whether this unusual food related behavior would lead to an increased prevalence of ingesting a poisonous substance.  

The subjects in this study included individuals with PWS, of ages four years old and older.  The survey was constructed online using the proprietary software of a commercial survey support website (SurveyMonkey.com).  Participants who completed the anonymous online survey were either the parents or the primary caretaker of individuals with PWS.  The participants also provided information about the non-PWS siblings, who served as controls. 

One hundred forty-one responses were submitted using the online survey.  Of these responses, 19.8% (N=26) of subjects reported at least one instance of poisoning, compared to 3% (N=4) in their non-PWS siblings.  There were a total of 43 episodes of ingestions in the 26 individuals, with a range of 1 to 5 different potential toxins per ingestion episode.

We used Statistical Analysis Software (SAS) to examine relationships between the variables.  The food-related behavior of ‘looking or searching for food’ was found to be related to poisoning (p=.025).  An individual with PWS who looked or searched for food was 2.5 times more likely to be poisoned than if they did not look or search for food. 

A second relationship was found between poisoning and the cognitive level of the PWS individual (p=.0009).  None of the PWS individuals reported as having ‘no retardation’ (N=7) had an instance of poisoning, whereas all of the PWS individuals reported as having ‘severe retardation’ (N=3) had at least one instance of poisoning.  10.7% (N=6) of the PWS individuals reported as having ‘developmental delay’ reported at least one instance of poisoning, 27.9% (N=12) of the PWS individuals reported as having ‘mild mental retardation’ reported at least one instance of poisoning, and 25% (N=5) of the PWS individuals reported as having ‘moderate mental retardation’ reported at least one instance of poisoning. 

A history of eating unusual objects in a PWS individual also showed a relationship to poisoning.  PWS individuals with a history of eating unusual objects were found to have a 5.7 fold increased risk of poisoning over the PWS individuals reported to not have such a history.  A history of extreme behaviors was also seen to have a relationship to poisoning.  PWS individuals reported as having histories of extreme behaviors were found to have a 2.2 fold greater risk of being poisoned than PWS individuals reported as not having histories of extreme behaviors.

This study found an increased prevalence of poisoning in people with PWS compared to their non-PWS siblings.  Several features of PWS, including the food-related behaviors (specifically ‘looking and searching for food’), decreased cognitive ability, eating unusual objects, and a history of extreme behaviors appear to correlate with this increased prevalence.  Awareness should be raised by alerting parents and caregivers of the increased prevalence of poisoning in people with PWS.    Primary care providers and poison control centers also need to be aware of this association, as well as the implications of PWS for diagnosing and treating ingestions.

June 2004