erythrocytosis—familial type 1
Definition An autosomal dominant disorder (OMIM:133100) characterised by increased red blood cell mass, increased haemoglobin and haematocrit, hypersensitivity of erythroid progenitors to erythropoietin, and low serum erythropoietin in a background of unaffected platelets and leukocytes. It has a relatively benign course and does not progress to leukaemia.
Molecular pathology Defects of EPOR, which encodes erythropoietin receptor that mediates erythroblast proliferation and differentiation, cause erythrocytosis—familial type 1.
Synonyms Polycythaemia—primary familial and congenital, erythrocytosis—autosomal dominant—benign