Axel Bolte, MSc, MBA, Co-Founder, President, and Chief Executive Officer, Inozyme Pharmaceuticals, gives an overview of ENPP1 deficiency.

The ENPP1 gene produces a critical enzyme called ectonucleotide pyrophosphatase/ phosphodiesterase 1 (ENPP1), which regulates inorganic pyrophosphate (PPi) levels in plasma. PPi is essential for preventing harmful soft tissue calcification and for regulating normal bone mineralization. Individuals who present in utero or in infancy are typically diagnosed with generalized arterial calcification of infancy (GACI), which is characterized by extensive vascular calcification and neointimal proliferation, resulting in myocardial infarction, stroke, or cardiac or multiorgan failure. 

Approximately 45% to 50% of infants with ENPP1 deficiency die within six months of birth. Children and adults with ENPP1 deficiency typically experience rickets and osteomalacia, a condition also known as autosomal-recessive hypophosphatemic rickets type 2 (ARHR2). These patients can also exhibit a range of signs and symptoms that include hearing loss, arterial calcification, and cardiac and/or neurological involvement. There are currently no approved therapies for ENPP1 deficiency. Recently, however, Inozyme announced positive preliminary biomarker, safety, and pharmacokinetic data from the first 3 patients treated in the phase 1 portion of its ongoing phase 1/2 clinical trial of INZ-701 in adult patients with ENPP1 deficiency.