Rickets

Rickets is a softening of the bones in children potentially leading to fractures and deformity. Rickets is one of the most frequent childhood diseases in many developing countries.

The main cause is a lack of vitamin D, but the lack of adequate calcium in the diet can also lead to rickets (cases of severe diarrhea and vomiting can be a cause of deficiency). Although it can occur in adults, most cases occur in children suffering from malnutrition, often due to hunger or starvation during the early stages of childhood.

Osteomalacia is the term used to describe a similar condition occurs in adults, generally due to lack of vitamin D. origin of the word "rickets" probably from Old English dialect word 'wrickken', to twist. Greek originated word "rachitis" (ραχίτις, which means "inflammation of the spine") was later adopted as a scientific term for rickets, especially because of the similarity of words' in the voice.

Those at high risk for developing rickets include:

* Breastfed babies whose mothers are not exposed to sunlight
* Breastfed babies are not exposed to sunlight
* Dark-skinned infants (eg black, South Africa), especially when milk and little exposed to sunlight
* Individuals do not consume milk, such as those who are lactose intolerant

Individuals with red hair have been speculated to have a reduced risk for rickets because of their greater production of vitamin D in sunlight.

Children ages 6 months to 24 months are at highest risk, because their bones are growing rapidly. Long-term consequences include permanent curvature or destruction of long bones, and back arched.

Vitamin D is needed for calcium absorption from the intestine. Sunlight, particularly ultraviolet light, allowing human skin cells to convert vitamin D from dormant to active state. In the absence of vitamin D, calcium is not properly absorbed, resulting in hypocalcemia, leading to bone and tooth defects and neuromuscular symptoms, eg hyperexcitability. Foods that contain vitamin D include butter, eggs, fish liver oils, margarine, milk and juice, and oily fish such as tuna, herring, and salmon.

A rare form of X-linked dominant there, called Vitamin D resistant rickets.