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.
Learner's definition of HARMFUL. [more harmful; most harmful] : causing or capable of causing damage or harm. The chemical kills harmful [=dangerous] bacteria. They claim that the drug has no harmful [=bad] side effects.