Polycythemia Vera: Genetic Predisposition and Clinical Implications

Introduction to Polycythemia Vera

Polycythemia vera (PV) is not inherited in a classic Mendelian pattern, but familial clustering occurs in approximately 7.6% of cases, suggesting a genetic predisposition to acquiring the causative JAK2 mutations rather than direct inheritance of the disease itself 1

The JAK2V617F mutation (present in >95% of PV cases) is an acquired somatic mutation, not a germline mutation passed from parent to child 1
PV is fundamentally a clonal stem cell disease where the disease-causing mutation occurs during a person's lifetime in their bone marrow cells 1, 2
The molecular lesion responsible for PV remains acquired at the cellular level, distinguishing it from truly hereditary conditions with Mendelian inheritance patterns 1

A higher disease incidence has been documented in persons of Jewish ancestry and among parent-offspring pairs 1, 2
Hereditary erythrocytosis includes conditions like high oxygen-affinity hemoglobinopathy (autosomal dominant) and 2,3-diphosphoglycerate mutase deficiency (autosomal recessive) 3
Some autosomal-dominant congenital polycythemia cases carry activating EPOR gene mutations, resulting in truncated receptors with enhanced signal transduction 3
Chuvash polycythemia represents another hereditary form with mutations in the von Hippel-Lindau gene 3

Children are rarely diagnosed with PV, with only approximately 7% of patients diagnosed before age 40 years 1, 2
When evaluating young patients with erythrocytosis and family history, measure serum EPO levels and consider hemoglobin electrophoresis to distinguish hereditary erythrocytosis from early-onset familial PV 3, 4