Context: Inherited forms of vitamin D deficiency are rare causes of rickets and to date have
been traced to mutations in three genes, VDR, encoding the 1α, 25-dihydroxyvitamin D …

Context: Production of the active vitamin D hormone 1, 25-dihydroxyvitamin D requires
hepatic 25-hydroxylation of vitamin D. The CYP2R1 gene encodes the principal vitamin D …

CYP2R1 is the principal hepatic 25-hydroxylase responsible for the hydroxylation of parent
vitamin D to 25-hydroxyvitamin D [25 (OH) D]. Serum concentrations of 25 (OH) D reflect …

Vitamin D requires a two‐step activation by hydroxylation: The first step is catalyzed by
hepatic 25‐hydroxylase (CYP2R1, 11p15. 2) and the second one is catalyzed by renal 1α …

The synthesis of bioactive vitamin D requires hydroxylation at the 1α and 25 positions by
cytochrome P450 enzymes in the kidney and liver, respectively. The mitochondrial enzyme …

Context: Mutations in the CYP27B1 gene, which encodes vitamin D 1α-hydroxylase, are the
genetic basis for vitamin D-dependent rickets type 1 (VDDR-I). Objective: The aim of this …

The CYP27B1 gene encodes 25-hydroxyvitamin D-1α-hydroxylase. Mutations of this gene
cause vitamin D-dependent rickets type 1A (VDDR-IA, OMIM 264700), which is a rare …

Abstract Background and Aims: Vitamin D-dependent rickets type I (VDDR1) is an
autosomal recessive disorder caused by mutations in the 25-hydroxyvitamin D 1-alpha …

Context Vitamin D‐dependent rickets type 1 A (VDDR‐IA, OMIM 264700) is a rare
autosomal recessive disorder and is caused by mutations in the CYP27B1 gene. Objectives …

Context: Vitamin D 1α-hydroxylase deficiency, also known as vitamin D-dependent rickets
type 1, is an autosomal recessive disorder characterized by the early onset of rickets with …