Augmentation de l'hémoglobine A2 au cours du pseudoxanthome élastique

The PXE phenotype seen in some patients with beta thalassemia appears to be associated with epigenetic modification of ABCC6 transcription and depends specifically on the beta globin locus. Isolated increase in HbA2 is probably a laboratory marker for PXE.Here again,a functional epigenetic reaction between ABCC6 and the beta-globin locus was suspected.However,these reciprocal interactions are clearly unequal since the change in ABCC6 transcription occurring during the course of beta thalassaemia is responsible for a PXE phenotype while increased HbA2 during the course of PXE has no clinical consequences.