MedGen

Autosomal dominant osteopetrosis-3 (OPTA3) is characterized by phenotypic variability. Some patients have typical features of osteopetrosis, including fractures after minor trauma, early tooth loss, anemia, hepatosplenomegaly, and a generalized increase in bone mineral density, whereas other patients exhibit localized osteosclerosis and generalized osteopenia. OPTA3 represents a relatively malignant form of osteopetrosis in some patients who develop significant pancytopenia and hepatosplenomegaly (Bo et al., 2016). For a discussion of genetic heterogeneity of autosomal dominant osteopetrosis, see OPTA1 (607634). [from OMIM]

Autosomal recessive osteopetrosis-6 (OPTB6) is a bone disorder of intermediate severity characterized by radiologic findings in childhood or adolescence of cortical sclerosis of the pelvic bones, and band-like sclerosis in metaphyses and metadiaphyses of femora, tibiae, and fibulae, and in vertebral endplates ('rugger jersey spine'). 'Erlenmeyer flask' deformity of distal femora may be present (van Wesenbeeck et al., 2007). For a general phenotypic description and a discussion of genetic heterogeneity of autosomal recessive osteopetrosis, see OPTB1 (259700). [from OMIM]