Association of both Langerhans cell histiocytosis and Erdheim-Chester disease linked to the BRAFV600E mutation.

Histiocytoses are a group of heterogeneous diseases that mostly comprise Langerhans cell histiocytosis (LCH) and non-LCH. The association of LCH with non-LCH is exceptional. We report 23 patients with biopsy-proven LCH associated with Erdheim-Chester disease (ECD) (mixed histiocytosis) and discuss the significance of this association. We compare the clinical phenotypes of these patients with those of 56 patients with isolated LCH and 53 patients with isolated ECD. The average age at diagnosis was 43 years. ECD followed (n = 12) or was diagnosed simultaneously with (n = 11) but never preceded LCH. Although heterogeneous, the phenotype of patients with mixed histiocytosis was closer to that of isolated ECD than to that of isolated LCH (principal component analysis). LCH and ECD improved in response to interferon alpha-2a treatment in only 50% of patients (8 of 16). We found the BRAF(V600E) mutation in 11 (69%) of 16 LCH lesions and in 9 (82%) of 11 ECD lesions. Eight patients had mutations in both ECD and LCH biopsies. Our findings indicate that the association of LCH and ECD is not fortuitous and suggest a link between these diseases involving the BRAF(V600E) mutation.

Evidence of postzygotic mosaicism in a transmitted form of Conradi-Hunermann-Happle syndrome associated with a novel EBP mutation.

BACKGROUND: X-linked dominant chondrodysplasia punctata, also known as Conradi-Hünermann-Happle syndrome, is a rare skeletal dysplasia characterized by short stature, craniofacial defects, cataracts, ichthyosis, coarse hair, and alopecia. Conradi-Hünermann-Happle syndrome is caused by mutations in the gene EBP encoding Δ(8)-Δ(7) sterol isomerase emopamil-binding protein. Random X-inactivation could account for the intrafamilial variability of the phenotype of X-linked dominant chondrodysplasia punctata. OBSERVATIONS: We describe a girl with clinical features of X-linked dominant chondrodysplasia punctata. Biochemical analysis showed an abnormal sterol profile consistent with a defect in Δ(8)-Δ(7) sterol isomerase. Molecular studies confirmed the diagnosis by identifying a novel heterozygous missense EBP mutation (c.199C>T; p.Cys67Arg). The mutation was not detectable on genomic DNA extracted from blood lymphocytes in both parents. The mother presented with an erythematous and ichthyosiform skin lesion. EBP analysis of DNA extracted from a lesional skin biopsy revealed the presence of p.Cys67Arg mutation. CONCLUSION: To our knowledge, we report the first molecular confirmation of postzygotic mosaicism on an ichthyosiform skin lesion in the mother of a girl with X-linked dominant chondrodysplasia punctata associated with a novel EBP mutation.

Secondary hyperaldosteronism in a patient with polyarteritis nodosa and renal artery aneurysms.

Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis that affects medium- and small-sized arteries. We report the case of a 32-year-old female with PAN in which renal involvement was revealed by a secondary hyperaldosteronism. Hypokaliemia and arterial hypertension preceded rupture of renal artery aneurysm by several months. We believe that hyperreninemia resulted from diffuse renal necrotizing vasculitis with occlusive but non-stenotic lesions. Angiography or CT scan should be performed systematically in PAN to screen for aneurysms so as to be able to consider prophylactic treatment by embolization and intensification of the general treatment. Hyperaldosteronism may reveal renal involvement in PAN and warrants an angiography if it has not yet been done.