Autosomal recessive hypophosphatemic rickets (ARHR) are of two types.

Autosomal recessive hypophosphatemic rickets (ARHR) type 1 occurs due to loss of function mutations in dentin matrix protein 1, a noncollagenous bone matrix protein expressed in osteoblasts and osteocytes. This protein has a role in osteocyte proliferation and in the downregulation of FGF23.

Another form of ARHR (ARHR 2) has been recently described. It occurs due to loss of function mutations in ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1). ENPP1 generates inorganic pyrophosphate (PPi), an essential physiologic inhibitor of calcification, and may be associated with aberrant ectopic calcification disorders (generalized arterial calcification of infancy) in some cases.

Clinical manifestations of patients with ARHR are similar to those with X-linked Hypophosphatemic rickets.

Biochemical findings of patients with ARHR are similar to those with X-linked Hypophosphatemic rickets.

The management of patients with ARHR is similar to those with X-linked Hypophosphatemic rickets.