MedGen

Aneurysmal bone cysts are benign primary or secondary lesions that are rapidly expansive and locally destructive. They are located in the posterior elements of the vertebral column or the flat or long bones of patients under 30 years of age. The cysts are blood-filled and separated by septa containing spindle cells, trabeculae of bone, and osteoclastic giant cells (Biesecker et al., 1970). Histopathologically and radiographically, aneurysmal bone cysts are similar to telangiectatic osteosarcoma from which they must be differentiated. [from OMIM]

C3 glomerulopathy (C3G) is a complex ultra-rare complement-mediated renal disease caused by uncontrolled activation of the complement alternative pathway (AP) in the fluid phase (as opposed to cell surface) that is rarely inherited in a simple mendelian fashion. C3G affects individuals of all ages, with a median age at diagnosis of 23 years. Individuals with C3G typically present with hematuria, proteinuria, hematuria and proteinuria, acute nephritic syndrome or nephrotic syndrome, and low levels of the complement component C3. Spontaneous remission of C3G is uncommon, and about half of affected individuals develop end-stage renal disease (ESRD) within ten years of diagnosis, occasionally developing the late comorbidity of impaired visual acuity. [from GeneReviews]