GeneDx offers another molecular test for patients with hypophosphatemic rickets. DMP1 mutations result in an autosomal recessive form of rickets characterized by hypophosphatemia and osteomalacia that affects both sexes equally. Other clinical features may include bowing of the lower limbs, poor dental development, extraskeletal ossification and elevated FGF23 serum levels. The clinical presentation of autosomal recessive hypophosphatemic rickets broadly overlaps with the more common X-linked form of hypophosphatemic rickets due to loss-of-function mutation in the PHEX gene.

 

DNA sequencing analysis of the coding region of the DMP1 gene is not only useful for confirming a clinical diagnosis and differentiating ARHR from the autosomal dominant and X-linked forms of hypophosphatemic rickets, it also allows for carrier testing of family members, helps to determine the recurrence risks in a family, and to offer the option of prenatal diagnosis in at-risk pregnancies.