This document summarizes rickets, a disease characterized by softening and weakening of bones in children due to a lack of vitamin D or calcium and phosphate. It discusses calcium, phosphate, and vitamin D metabolism and how deficiencies can lead to inadequate mineralization of bone. Symptoms include bone pain, deformities like bowed legs, and fractures. Diagnosis involves biochemical testing showing low calcium, phosphate, and vitamin D levels as well as characteristic findings on x-rays of bones. Treatment is supplementation to correct nutritional deficiencies.