ABSTRACT
Reports on clinical cases of orphan pathologies, as autosomal recessive type of infantile malignant osteopetrosis, have a great practical importance for scholars. Osteopetrosis may already manifest itself in utero. In early childhood, there is a classic triad of symptoms: increased bone density and fragility, severe anemia. Diagnostics and allogeneic hematopoietic stem cell transplantation at the age of up to 1 year can be cured and significantly increase life expectancy. Bone marrow transplantation is only treatment that has been proven to significantly alter course of autosomal recessive type of osteopetrosis. Inspide of successful transplantation may or-thopaedic, dental problems and their vision rarely significantly improves, however haemopoietic potential is restored and the long term prognosis is favourable. Herein we report a case of patient diagnosed with osteopetrosis and underwent allogeneic hematopoietic stem cell transplantation, with no prior determination type of mutation. Complexity of case: late diagnosis autosomal recessive type of osteopetrosis (at 3.1 years), despite characteristic early clinical manifestations, a protracted preparatory period associated with search for an unrelated donor and COVID-19 pandemic, for allogeneic-hematopoietic stem cell transplantation performed at the age of 4.3 years. In resulting, was engraftment of bone marrow transplant, with restoration hematopoietic func-tion, but with preserved neurological and physical disabilities in a form of psychomotor develop-ment retardation. Allogeneic hematopoietic stem cell transplantation led to restoration hematopoietic function of the graft in this case of late diagnosis osteopetrosis.