An autosomal recessive form of osteopetrosis caused by mutation(s) in at least 8 genes related to osteoclast function. This condition is characterized by the failure of osteoclasts to resorb bone, resulting in impaired bone modeling/remodeling, and skeletal fragility despite increased bone mass; it is also associated with hematopoietic insufficiency, hypocalcemia, disturbed tooth eruption, nerve entrapment syndromes, and growth impairment. Some cases are also associated with progressive neurological deterioration. The disease is autosomal recessive osteopetrosis (Monarch Disease Ontology term MONDO_0019026). Also known as: OPTB, autosomal recessive malignant osteopetrosis, autosomal recessive osteopetrosis (disease), infantile malignant osteopetrosis, osteopetrosis (disease), autosomal recessive.