SOST and sclerosteosis: In humans, genetic mutations in the SOST gene, which encodes SCLEROSTIN, cause sclerosteosis, an autosomal recessive disease characterized by high bone mass and bone tissue overgrowth.183 Similar to the results of human genetic studies, Sost deletion in mice resulted in a high bone mass throughout life, and these mice exhibited fewer apoptotic osteocytes and apoptotic osteoblasts in their bone tissue with enhanced Wnt//β-Catenin signaling.184