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.
Nature of a toxic substance. Definition of a poison. A poison is a substance capable of producing adverse effects on an individual under appropriate conditions. The term âsubstanceâ is almost always synonymous with âchemicalâ and includes drugs, vitamins, pesticides, pollutants, and proteins. Even radiation is a toxic substance.