Edwards' syndrome is caused by an extra (third) copy of chromosome 18. The extra chromosome is lethal for most babies born with this condition. It causes major physical abnormalities and severe mental retardation . Very few children afflicted with this syndrome survive beyond the first year. Edwards' syndrome is associated with the presence of a third copy of chromosome number 18. Humans normally have 23 pairs of chromosomes. Chromosomes are numbered 1–22, and the 23rd pair is composed of the sex chromosomes, X and Y. A person inherits one set of 23 chromosomes from each parent. Occasionally, a genetic error occurs during egg or sperm cell formation. A child conceived with such an egg or sperm cell may inherit an incorrect
Edwards' syndrome is caused by an extra (third) copy of chromosome 18. The extra chromosome is lethal for most babies born with this condition. It causes major physical abnormalities and severe mental retardation . Very few children afflicted with this syndrome survive beyond the first year. Edwards' syndrome is associated with the presence of a third copy of chromosome number 18. Humans normally have 23 pairs of chromosomes. Chromosomes are numbered 1–22, and the 23rd pair is composed of the sex chromosomes, X and Y. A person inherits one set of 23 chromosomes from each parent. Occasionally, a genetic error occurs during egg or sperm cell formation. A child conceived with such an egg or sperm cell may inherit an incorrect