A disease in children in which an inefficient mineralization of the bone-forming tissue causes deformities is:

Rickets is the disease in children in which an inefficient mineralization of the bone forming tissue causes deformities. This condition results in weak or soft bones in children, normally due to an extreme and prolonged deficiency of vitamin D. Vitamin D promotes the absorption of calcium and phosphorus from the gastrointestinal tract. The symptoms include bowed legs, stunted growth, bone pain, large forehead, and trouble sleeping among others.