Prader-Willi is a genuine genetic defect that causes developmental issues that actually influence brain structure and function. Its effects appear on a continuum: some Prader-Willi sufferers function with normal or nearly normal intelligence (depending on what passes for normal in their surroundings), but that requires therapy and enrichment from people familiar with their neural deficits. Some Prader-Willi sufferers are fit and trim - but this requires even more family support, drugs, behavioral therapy, and keeping food locked up and access to money restricted.  Has anyone ever begged you to buy food for them? Think twice -- even if they are slender, they may be a person with Prader-Willi who has slipped out of supervision. Some low-functioning Prader-Willi eat drywall, sponge, carpet: it's not pica, it's unrelenting compulsion. Parenting a Prader-Willi child is an endless nightmare of dreading that they will kill themselves by eating massive quantities of everything and anything, especially if you actually love them, work with them so their abilities have a chance to emerge, and hold out hope for a "cure."  These parents suck, have ruined their own bodies and lives, and shouldn't be allowed to have control over children or animals .