Heredity & Vitamin D Deficiency

Vitamin D deficiency is a common disorder in both children and adults. In children, it can cause bone abnormalities and interfere with their growth. In adults, it can lead to osteoporosis and muscle weakness. Several causes of this disorder may include obesity, Crohn's disease, celiac disease and sunscreens. Plus, some hereditary diseases can cause a vitamin D deficiency as well.

Renal 1 Alpha-Hydroxylase Deficiency

Whenever the calcium level in the bloodstream is low, the parathyroid gland sends the parathyroid hormone to the bones and kidneys. The hormone tells the enzyme 1 alpha-hydroxylase within the kidneys to change the inactive form of vitamin D to the active form. People with a renal 1 alpha-hydroxylase deficiency have a hereditary disease. They have a vitamin D deficiency because they do not have enough of the 1 alpha-hydroxylase enzyme to make the active form of vitamin D, as explained in "Harrison's Principles of Internal Medicine" by F. Richard Bringhurst, M.D., associate professor of medicine at Harvard Medical School.

Type II Hereditary Vitamin D-Dependent Rickets

Renal 1 alpha-hydroxylase deficiency is also called type I hereditary vitamin D-dependent rickets because a vitamin D deficiency can lead to rickets, a disorder where children have soft bones. Type II hereditary vitamin D-dependent rickets is a hereditary disease that can result in a vitamin D deficiency and rickets, but it is caused by a mutation. There is a problem with the vitamin D receptors, or proteins on or inside a cell, doing what they are told. These receptors are in the bones, stomach, intestines and kidneys, according to Larry Johnson, M.D., Ph.D., attending physician at the Central Arkansas Veterans Healthcare System in "The Merck Manual for Healthcare Professionals."

Type III Hereditary Vitamin D-Dependent Rickets

Type III hereditary vitamin D-dependent rickets is a genetic disorder in which some people make too much of a protein called the hormone-response element-binding protein. This type of protein is involved in turning on genes, but too much of the protein can interfere with vitamin D attaching to the vitamin D receptors, explains Michael Holick, M.D. Ph.D., of the Department of Medicine at Boston University Medical Center in the August 2006 issue of "The Journal of Clinical Investigation." In type II hereditary vitamin D-dependent rickets, there is a problem with the vitamin D receptor itself. In type III, a protein interferes with the receptor; the receptor itself is fine.

Symptoms

Someone with a deficiency in vitamin D can have bone pain and muscle weakness no matter what the genetic reason, or nongenetic reason, for that matter. If a pregnant woman has this deficiency, it can result in the fetus having the deficiency as well, says Johnson. A young infant can have a soft skull, and an older infant may take longer to crawl and sit. It can take longer for a child to learn to walk, and the child can develop knock-knees and bowed legs. Adults can develop fractures, which can happen as a result of only a small amount of trauma.