Rickets is a rare disease that results in soft, weak, and pliable bones. It is caused mainly by a lack of vitamin D.

Rickets most commonly affects children, who may have low vitamin D levels due to poor diet or a condition (such as celiac disease) that makes it difficult for the body to absorb vitamin D and calcium.

Rickets can lead to bone deformities such as bowlegs, knock-knees, an enlarged skull, and an abnormal curve in the spine. It also can cause weakness.