Biclonal lymphoproliferative disorders: another association with NOTCH1-mutated chronic lymphocytic leukaemias

Introduction: Biclonal lymphoid disorders, when two distinct lymphoproliferative disorders (LPD) co-exist, are rare (incidence of 1.4%) and associated with a poor prognosis. NOTCH1 mutations occur in 10% of CLL at diagnosis, associated with a short disease-free interval and increased risk of Richter's transformation. We hypothesised that the incidence of NOTCH1 mutations in CLL with a second LPD may be increased, because the mutation occurs early in leukaemogenesis, permitting clonal divergence.Methods: We identified 19 patients with biclonal LPD at diagnosis: 11 with CLL and a second LPD (group A) and 8 with a second distinct CLL (group B). NOTCH1 mutation analysis was performed and clinical outcome investigated.Results: Ten of 19 (52%) were NOTCH1 mutated: 5 in group A (45%) and 5 in group B (62.5%) with a favourable clinical outcome observed among this cohort with 28.7 (range 1-99) months of follow-up.Conclusion: In conclusion, we identified a significant (52%) incidence of NOTCH1 mutations in CLL in the context of biclonal LPD, associated with an indolent clinical course.</p

Extreme genetic depletion upon postglacial colonization hampers determining the provenance of introduced palmate newt populations

Abstract MtDNA barcoding is regularly applied to determine the provenance of invasive species. Variation in spatial genetic structuring across a species’ range, typically high within glacial refugia and low in postglacially colonized areas, influences the precision of this approach. The palmate newt (Lissotriton helveticus) has been introduced north of its native range inside the Netherlands. We conduct mtDNA barcoding to try and retrace the origin of the introduced localities. A large increase in sample size, particularly focusing on temperate Europe, emphasizes that the palmate newt shows practically no genetic variation outside the Iberian Peninsula glacial refugium. While we find a haplotype previously only known from the Iberian Peninsula inside the native range in Belgium, the haplotype present in the introduced Dutch populations occurs widely throughout the native range north of the Iberian Peninsula. Although mtDNA barcoding can be a powerful tool in invasion biology, the palmate newt case exposes its limitations