Table I.
Genes associated with erythrocytosis
| Gene | Effect on protein | Type |
|---|---|---|
| JAK2 | Gain of function, impaired auto-inhibitory domain | PV |
| EPOR | Gain of function, increased activation of signalling cascade | ECYT1 |
| VHL | Loss of function, impaired degradation of HIF2α | ECYT2 |
| EGLN1 (PHD2) | Loss of function, impaired degradation of HIF2α | ECYT3 |
| EPAS1 (HIF2A) | Gain of function, increased stabilityin normoxia | ECYT4 |
| EPO | Gain of function, increased expression in normoxia | ECYT5 |
| HBB | Loss of function, increases Hb affinity for O2 | ECYT6 |
| HBA1 & HBA2 | Loss of function, increases Hb affinity for O2 | ECYT7 |
| BPGM | Loss of function, impaired synthesis of 2,3-BPG | ECYT8 |
PV: polycythaemia vera; ECYT: familial er ythroctyosis; HIF-2α: hypoxia-inducible factor 2-alpha; Hb: haemoglobin; O2: oxygen; 2,3-BPG: 2,3-bisphosphoglycerate.