Variants in the new E1' cryptic exon of the gene associated with congenital erythrocytosis-Description of three cases.

Congenital erythrocytosis (CE) represents a rare and heterogeneous group of hereditary disorders. The molecular basis of gene mutations related to CE. Recently, Lenglet et al. reported a discovery of a novel cryptic exon in the gene. Mutations in the first intronic region resulting in the creation of a cryptic exon termed E1' were found in seven families with CE and one family with VHL disease. We report three patients with prolonged CE with the aetiology being clarified several years later by sequencing of intronic region 1 of the gene. This work addresses the first cases reported at the clinical level of VHL-associated CE due to the E1' cryptic exon.