Multiple endocrine and other organ neoplasia syndromes

The multiple endocrine and other organ neoplasia syndromes (MEONSs) are a heterogeneous group of monogenic disorders characterized by the development of endocrine neoplasia alongside a range of nonendocrine tumors. The MEONS include the hyperparathyroidism-jaw tumor syndrome, Von Hippel-Lindau disease, Carney Complex, Neurofibromatosis type 1, Cowden syndrome, and McCune-Albright syndrome. Each of these is typically inherited as an autosomal dominant disorder, except MAS, which is due to a mosaic expression of a postzygotic somatic GNAS variant. The MEONS are associated with a range of skeletal diseases that include osteoporosis, scoliosis, pseudoarthroses, long bone and spinal dysplasias, ossifying tumors, and osteochondromyxomas.