<prompt> Childhood osteopetrosis is characterized by a BL frontal bossingb Multiple fracturec Hepatosplenomegalyd Cataracte Mental retardationbccacad  <response>: Osteopetrosis Osteopetrosis is an autosomal recessive heredofamilial disorder in which partly calcified cartilaginous intercellular ground substance is not regularly reabsorbed replaced by regular osteoid tissue bone.Manifested by :Increased bone density masking the distinction between cortex medulla, bone within bone appearance Marbles bone.Brittle bone easily fracturabilityFracture healing satisfactory resulting in skeletal deformities.Myelophthisic anemiaHepatosplenomegaly presence of immature leukocytes normoblasts in the peripheral blood.Growth retardation,Macrocephaly.Thickening of cranial foramina thus causing pressure on optic nerve optic atrophy.Deafness blindnessDental problems osteomyelitis of the mandible.Learning disorder but may have normal intelligence despite hearing visual loss. 