Coexistence of multiple gene variants in some patients with erythrocytoses

Abstract

Background: Erythrocytosis is a relatively common condition, however a large proportion of these patients (70%) remain without a clear etiologic explanation.  Methods: We set up a targeted NGS panel for patients with erythrocytosis and 118 sporadic patients with idiopathic erythrocytosis were studied. Results: In 40 (34%) patients no variant was found while in 78 (66%) we identified at least one germinal variant; 55 patients (70.5%) had 1 altered gene, 18 (23%) had 2 alterations, and 5 (6.4%) had 3. An altered HFE gene was observed in 51 cases (57.1%), EGLN1 in 18 (22.6%) and EPAS1, EPOR, JAK2, and TFR2 variants in 7.7%, 10.3%, 11.5%, and 14.1% patients, respectively. In 23 patients (19.45%), more than 1 putative variant was found in multiple genes. Conclusions: Genetic variants in patients with erythrocytosis were detected in about 2/3 of our cohort. A NGS panel including more candidate genes should reduce the number of cases diagnosed as “idiopathic” erythrocytosis in whom a cause cannot yet be identified. It is known that HFE variants are common in idiopathic erythrocytosis. TFR2 alterations supports the existence of a relationship between genes involved in iron metabolism and impaired erythropoiesis. Some novel multiple variants were identified. Erythrocytosis appears to be often of multigenic nature.