What is the mortality and morbidity associated with Prader-Willi syndrome (PWS)?

Updated: Oct 14, 2020
  • Author: Ann Scheimann, MD, MBA; Chief Editor: Luis O Rohena, MD, MS, FAAP, FACMG  more...
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Complications due to obesity (eg, slipped capital femoral epiphyses, sleep apnea, cor pulmonale, type 2 diabetes mellitus) and behavioral problems are major contributors to morbidity and mortality in individuals with Prader-Willi syndrome (see Complications). Lamb et al reported premature development of atherosclerosis with severe coronary artery disease in a patient aged 26 years with Prader-Willi syndrome, morbid obesity, and non–insulin-dependent diabetes mellitus. [33]

A study by Brito et al reported that in pediatric subjects with Prader-Willi syndrome, total heart rate variability during slow-wave sleep was lower than in obese-matched controls and sex- and age-matched lean controls. The investigators stated that during slow-wave sleep, the children with Prader-Willi syndrome experienced impaired cardiac autonomic balance as a result of reduced parasympathetic modulation. The study suggested that in patients with Prader-Willi syndrome, cardiovascular disease risk is greater even at an early age, with an underlying cause that exists independent of the effects of obesity. [34]

Wharton et al described a series of 6 patients with Prader-Willi syndrome with dramatic acute gastric distention preceded by symptoms of gastroenteritis. [13] One half of the cases rapidly progressed to massive gastric dilatation and gastric necrosis. One patient died of overwhelming sepsis and disseminated intravascular coagulation. Gastric dilatation spontaneously resolved in 2 children. Gastrectomy was performed in 2 patients; in one patient, gastrectomy was subtotal and distal, whereas in the other patient, gastrectomy was combined with partial duodenectomy and pancreatectomy. An autopsy series by Stevenson et al reported gastric rupture and necrosis as the confirmed cause of death in 3% of the patients with Prader-Willi syndrome, with another 4 suspected cases of gastric necrosis. [14]

In a series of 152 patients with Prader-Willi syndrome, choking episodes were reported as the cause of death in 7.9%. [35]

Another series of patients noted 8 children and 2 adults who had unexpected death, with small adrenal glands noted in 3 of 8 children, raising suspicion for underlying adrenal insufficiency. [36] Subsequent studies have disputed the frequency of central adrenal insufficiency proposed by these authors, believing it to be a rare occurrence. [37]

Assessing a 40-year mortality survey from the Prader-Willi Syndrome Association (USA), Manzardo et al found measurable increases in survival in Prader-Willi syndrome with regard to cardiovascular- and gastrointestinal-related problems. The investigators said the change was probably the result of "earlier diagnosis and proactive interventions to prevent morbid obesity." [38]

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