Vitamin D Dependent Rickets 2b

**Semantic type:** Disease or Syndrome

**Definition:** Rickets caused by a post-receptor defect in the vitamin D signaling pathway producing vitamin D resistance due to constitutive overexpression of a nuclear ribonucleoprotein that competes with the vitamin D receptor-retinoid X receptor dimer binding with DNA vitamin D response elements. This condition has a similar phenotype to vitamin D receptor deficiency rickets including elevated 1,25-dihydroxyvitamin D (calcitriol) concentrations.

**Synonyms:** - Hereditary 1,25 Dihydroxyvitamin D-Resistant Rickets with Abnormal Vitamin D Receptor without Alopecia - Vitamin D Receptor Signaling Defect Rickets - Vitamin D Resistant Rickets