Although the disease was first described by Bryant and White in 1901 (ref. 10), it was not until 2000 that Rutsch et al. 11 noted that serum plasma inorganic pyrophosphate (PPi) levels and ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) enzymatic activity were significantly impaired in GACI patients. The gene discussed is ENPP1; the disease is arterial calcification, generalized, of infancy, 1.