VDR
vitamin D receptor
Normal Function
Health Conditions Related to Genetic Changes
Vitamin D-dependent rickets
Mutations in the VDR gene cause vitamin D-dependent rickets type 2A (VDDR2A), also known as hereditary vitamin D-resistant rickets (HVDRR). This disorder of bone development is characterized by low levels of calcium (hypocalcemia) and phosphate (hypophosphatemia) in the blood, which lead to soft, weak bones (rickets) that are prone to fracture. A common feature of this condition is abnormally curved (bowed) legs.
The VDR gene mutations that cause this condition prevent the VDR protein from functioning properly. Some changes in the VDR gene lead to an abnormally short version of the VDR protein. Others result in the production of an abnormal receptor that cannot bind to calcitriol, to RXR, or to DNA. Although there is plenty of calcitriol in the body, the altered VDR protein cannot stimulate gene activity important for mineral absorption. The lack of calcium and phosphate absorption in the intestines slows deposition of these minerals into developing bone (bone mineralization), which leads to soft, weak bones and other features of VDDR2A. Hypocalcemia also causes muscle weakness and seizures in some affected individuals. Most VDR gene mutations impair hair growth, leading to hair loss (alopecia); however, mutations that block VDR's ability to interact with calcitriol do not cause alopecia, indicating that calcitriol is not necessary for the receptor's role in hair development.
More About This Health ConditionRelated Conditions
Vitamin D-dependent ricketsAlopecia areataIntervertebral disc diseaseKidney stonesLeprosy
Health Conditions Related to Genetic Changes
Mutations in the VDR gene cause vitamin D-dependent rickets type 2A (VDDR2A), also known as hereditary vitamin D-resistant rickets (HVDRR). This disorder of bone development is characterized by low levels of calcium (hypocalcemia) and phosphate (hypophosphatemia) in the blood, which lead to soft, weak bones (rickets) that are prone to fracture. A common feature of this condition is abnormally curved (bowed) legs.
The VDR gene mutations that cause this condition prevent the VDR protein from functioning properly. Some changes in the VDR gene lead to an abnormally short version of the VDR protein. Others result in the production of an abnormal receptor that cannot bind to calcitriol, to RXR, or to DNA. Although there is plenty of calcitriol in the body, the altered VDR protein cannot stimulate gene activity important for mineral absorption. The lack of calcium and phosphate absorption in the intestines slows deposition of these minerals into developing bone (bone mineralization), which leads to soft, weak bones and other features of VDDR2A. Hypocalcemia also causes muscle weakness and seizures in some affected individuals. Most VDR gene mutations impair hair growth, leading to hair loss (alopecia); however, mutations that block VDR's ability to interact with calcitriol do not cause alopecia, indicating that calcitriol is not necessary for the receptor's role in hair development.
MedlinePlus Genetics provides information about Alopecia areata
MedlinePlus Genetics provides information about Intervertebral disc disease
MedlinePlus Genetics provides information about Kidney stones
MedlinePlus Genetics provides information about Leprosy