Variant	Inheritance pattern	Pathophysiology	Clinical features	Age of onset	Prognosis
Osteopetrosis tarda	Autosomal dominant	Abnormal osteoclastic bone resorption	No bone marrow failure; brittle bones; increased susceptibility to fractures but with normal healing; degenerative joint disease; 50% of patients are asymptomatic	Adulthood	Good
Osteopetrosis congenita	Autosomal recessive	Abnormal osteoclastic bone resorption	Severe bone marrow failure; pancytopenia; bleeding; infection; failure to thrive; growth retardation; proptosis; blindness; deafness; hydrocephalus	Infancy	Poor
Marble bone disease	Autosomal recessive	Abnormal osteoclastic bone resorption	No bone marrow failure; renal tubular acidosis; intracranial calcifications; sensorineural hearing loss; psychomotor retardation	Childhood	Poor