In people with immature bone growth, Vitamin D deficiency leads to soft and easily fractured bones. This often leads to the longer bones in the arm and leg becoming either shortened and/or deformed.
Rickets was once common in North American African-Americans, who had little dietary vitamin D and produced less of the vitamin through exposure of skin to sunlight. However, since milk became fortified with the vitamin and other supplements like fish liver oil became more common, the disease has become very rare. It is now only common in infants with severe malnutrition.