Vitamin D-Resistant Rickets, Type IIA (VDR)
Vitamin D-resistant Rickets, type IIA is an autosomal recessive hereditary vitamin D disorder caused by pathogenic variants in the gene VDR. The age of onset of this disorder is typically in infancy. Common clinical manifestations include hypocalcemia (low levels of calcium in the blood), secondary hyperparathyroidism, bone abnormalities, muscle weakness, hypotonia, bone pain and fractures, growth delays, and dental abnormalities such as thin enamel and frequent cavities. Many individuals may also have sparse hair to alopecia (complete hair loss). With appropriate treatment, life expectancy is expected to be normal. No clear genotype-phenotype correlation has been established.
For information about carrier frequency and residual risk, please see the residual risk table.