Summary of clinical features and outcomes of type 1–like vs type 2–like CALR mutations
| . | Type 1–like CALR . | Type 2–like CALR . |
|---|---|---|
| Most common mutation | 52-bp deletion (L367fs*46) | 5-bp insertion (K385fs*47) |
| Prevalence | More common in MF | More common in ET |
| Clinical (ET) | Similar; lower platelet counts vs type 2 like | Similar; higher platelet counts vs type 1 like |
| Clinical (MF) | Less splenomegaly, leukocytosis, anemia, and circulating blasts; lower DIPSS score; higher platelets (all vs type 2 like) | More splenomegaly, leukocytosis, anemia, and circulating blasts; higher DIPSS score; lower platelets (all vs type 1 like). More similar to JAK2 V617F |
| Post-ET MF | Similar to/increased vs type 2 like | Similar to/decreased vs type 1 like |
| Overall prognosis (ET) | Similar to type 2 like | Similar to type 1 like |
| Overall prognosis (MF) | Improved vs type 2 like and JAK2 V617F | Worsened vs type 1 like; more similar to JAK2 V617F |
| . | Type 1–like CALR . | Type 2–like CALR . |
|---|---|---|
| Most common mutation | 52-bp deletion (L367fs*46) | 5-bp insertion (K385fs*47) |
| Prevalence | More common in MF | More common in ET |
| Clinical (ET) | Similar; lower platelet counts vs type 2 like | Similar; higher platelet counts vs type 1 like |
| Clinical (MF) | Less splenomegaly, leukocytosis, anemia, and circulating blasts; lower DIPSS score; higher platelets (all vs type 2 like) | More splenomegaly, leukocytosis, anemia, and circulating blasts; higher DIPSS score; lower platelets (all vs type 1 like). More similar to JAK2 V617F |
| Post-ET MF | Similar to/increased vs type 2 like | Similar to/decreased vs type 1 like |
| Overall prognosis (ET) | Similar to type 2 like | Similar to type 1 like |
| Overall prognosis (MF) | Improved vs type 2 like and JAK2 V617F | Worsened vs type 1 like; more similar to JAK2 V617F |