A deficiency in vitamin D is characterized by a condition known as osteomalacia or rickets in children. Vitamin D is essential for calcium absorption and maintaining bone health. Insufficient levels can lead to weakened bones, increasing the risk of fractures and skeletal deformities. Symptoms may include muscle weakness and increased susceptibility to infections. This deficiency can result from limited sun exposure, poor dietary intake, or certain health conditions that affect absorption. Addressing vitamin D deficiency is crucial for ensuring optimal bone health and overall well-being.