Most disorders of missing chromosomes involve only partially missing chromosomes, with one exception:
Turner syndrome happens when the baby girl has a single X chromosome instead of a pair of X chromosomes. People with Turner syndrome tend to be short, have normal intelligence, and may need hormone therapy to induce puberty. Many need fertility help to get pregnant.
Prader-willi Syndrome is caused by a partial absence of the 15th chromosome. Most of the symptoms are behavioral, including constant hunger, which can result in obesity and an increased risk of type 2 diabetes.
Cri-du-chat (French for “cry of a cat”) syndrome babies have a partially missing 5th chromosome. It can be fairly severe or fairly mild. It’s name comes from the characteristic way that newborns with this syndrome sound like a cat when they cry.
Most of these happen randomly and are not inherited.