Mutations in these genes give rise to other rare variants of hypophosphatemic rickets, including autosomal dominant hypophosphatemic rickets (ADHR), autosomal recessive hypophosphatemic rickets type 1 (ARHR1) and autosomal recessive hypophosphatemic rickets type 2 (ARHR2), collectively constituting less than 20% of the cases (10). Here, ENPP1 is linked to autosomal dominant hypophosphatemic rickets.