Characteristics of Prader-Willi Syndrome Prader-Willi Syndrome (PWS) is a genetic condition caused by abnormalities in chromosome 15. PWS affects both males and females of all races. The currently accepted incidence rate is 1: 12,000-15,000. The following is a list of common characteristics of Prader-Willi Syndrome. Each person affected by PWS is unique. Each person exhibits characteristics in varying degrees and may not exhibit all characteristics listed. Infancy Hypotonia (low muscle tone) Poor suck reflex, contributing to feeding difficulties and poor weight gain Respiratory issues, including hypoventilation Global developmental delay Hypogonadism. In males, undescended testes or small penis and/or testes. In females, absence of labia minora and/or clitoris. Characterisic facial features (narrow forehead, almond shaped eyes, small mouth with thin upper lip, mouth down-turned at corners) Often, there is reduced fetal movement, low birth weight, infantile lethargy and weak cry. Childhood to Adulthood Onset of hyperphagia (persistent urge to eat, lack of satiation) with food foraging becoming evident Dramatic weight gain, in absence of diet management, with a concentration of weight in the central body region Reduced muscle mass with high fat-to-muscle ratio Behavioural problems (tantrums, violent outbursts, rigidity, perseveration, stealing, lying) Sleep difficulties, including sleep apnea Intellectual impairment, with average IQ of 70 Learning deficits (poor short term memory and auditory discrimination) Short stature with small hands and feet, without growth hormone therapy Delayed or incomplete puberty Risk of morbid obesity, in absence of diet management Increased risk of serious health problems, due to obesity (diabetes, cardiac and respiratory complications) Increased risk of scoliosis and osteoporosis Skin picking Excessive daytime sleepiness High pain threshold Lack of vomit reflex Increased saliva, which is thick and viscous Eye abnormalities Follow the link to  www.pwsausa.org   for the list of diagnostic criteria for Prader-Willi Syndrome, based on the work of Holm et al. (Pediatrics 91, 398, 1993). Interventions and Management Early diagnosis is most beneficial in the management of Prader-Willi Syndrome. Dietary Management Dietary intervention and exercise are essential, especially when food foraging behaviours become evident. A dietitian or nutritionist will help parents develop a diet plan that balances caloric intake and proper nutrition. Physiotherapy and Occupational Therapy Physiotherapists and occupational therapists can set up a program to help children improve gross and fine motor skill development, suggesting exercises and equipment that help with this process. Speech/Language Therapy A speech/language pathologist will assist in the development of speech and language skills. Behaviour Intervention People who have Prader-Willi Syndrome require consistency, structure and routine to thrive. Maladaptive behaviours can have many sources. There are many specialists who can help discover the causes of maladaptive behaviours, including occupational therapists specializing in sensory integration, physicians, child psychologists, counselors, teachers and psychiatrists. Proper management techniques can help minimize the frequency of occurrence of maladaptive behaviours. Endocrinology Growth hormone and sex hormone (testosterone and estrogen) levels are typically low. Hormone therapy can help alleviate problems associated with hormone deficiencies.