A rare genetic osteolysis syndrome resulting from protein-truncating variants in exon 34 of the NOTCH2 gene. These variants disrupt only the PEST domain, escape nonsense-mediated decay, and are postulated to function through a gain-of-function mechanism. This condition is characterized by acroosteolysis of distal phalanges and generalized osteoporosis, associated with additional ossification anomalies, craniofacial dysmorphism, dental anomalies and a wide range of other characteristics. Hearing loss, renal cysts, and cardiovascular anomalies are variably present.