Called juvenile osteomalacia. It is an abnormal mineralization and development of the growth plate of bone leading to bone pain, growth retardation, and fatigability.

Rickets results from deficient vitamin D, calcium, and phosphorus, caused by malabsorption or dietary restrictions.

Especially during growth, bone is sensitive to nutritional factors. Calcium deficiency leads to incomplete calcification of the organic bone matrix. Calcium deficiency can be due to a lack of calcium in the diet or a failure to produce the steroid prohormone vitamin D, which is important for the absorption of Ca2+ and PO3-4 by the small intestine.

Calcium deficiency in children causes rickets, the bone matrix does not calcify normally and the epiphyseal plate becomes distorted by the normal strains of body weight and muscular activity. Ossification processes at this level are consequently hindered, and the bones not only grow more slowly but also become deformed.

Calcium deficiency in adults gives rise to osteomalacia which is characterized by deficient calcification of recently formed bone and partial decalcification of already calcified matrix.

Rickets can also be caused by Type I hepatorenal tyrosinemia. A rare autosomal recessive disease characterized by the absence of fumarylacetoacetate hydrolase. Symptoms include liver failure, renal rubular dysfunction, rickets, polyneuropathy, and a cabbage-like smell.

In Type I hepatorenal tyrosinemia, fumaryl acetoacetate and maleylacetate accumulate.

Clinical manifestations of nutritional rickets/osteomalacia include demineralization of bones and susceptibility to fractures.

Renal rickets (renal osteodystrophy) is characterized by chronic renal failure, which leads to decreased ability to form the active vitamin D.

Calcium deficiency in children causes rickets.

The bone matrix does not calcify normally and the epiphyseal plate becomes distorted by the normal strains of body weight and muscular activity. Ossification processes at this level are consequently hindered, and the bones not only grow more slowly but also become deformed.

- Growth plate become thicker and less regular than normal.
- In rickets, uncalcified or poorly calcified cartilage trabeculae are only partially eroded; osteoblasts secrete layers of osteoid, but these fail to ossify in the metaphyseal region, and ultimately gravity deforms these softened bones.