ENPP1 and osteoporosis: Interestingly, another study detected monoallelic pathogenic ENPP1 variants previously identified in GACI patients with biallelic ENPP1 deficiency (rs148462924 [GnomAD: 0.00011, ToMMo: not listed], rs147346173 [GnomAD: 0.00026, ToMMo: not listed]), but the monoallelic patients (60- and 69-year-old males) exhibited early-onset osteoporosis and multiple vertebral compression fractures.