Prader-Willi syndrome is caused by a missing gene on chromosome 15. Normally, parents each pass down a copy of this chromosome. The defect can occur in a couple of ways: The father's genes are missing on chromosome 15; There are defects or problems with the fatherâs genes on chromosome 15
poison meaning, definition, what is poison: a substance that can make people or animals ill or kill them if they eat or drink it: . Learn more.
toxic-of or relating to or caused by a toxin or poison; suffering from exposure to toxic substances. harmful-causing or capable of causing harm; too much sun is harmful to the skin; harmful effects of smoking.