The complex karyotype in hematological malignancies: a comprehensive overview by the Francophone Group of Hematological Cytogenetics (GFCH).

Karyotype complexity has major prognostic value in many malignancies. There is no consensus on the definition of a complex karyotype, and the prognostic impact of karyotype complexity differs from one disease to another. Due to the importance of the complex karyotype in the prognosis and treatment of several hematological diseases, the Francophone Group of Hematological Cytogenetics (Groupe Francophone de Cytogénétique Hématologique, GFCH) has developed an up-to-date, practical document for helping cytogeneticists to assess complex karyotypes in these hematological disorders. The evaluation of karyotype complexity is challenging, and it would be useful to have a consensus method for counting the number of chromosomal abnormalities (CAs). Although it is not possible to establish a single prognostic threshold for the number of CAs in all malignancies, a specific consensus prognostic cut-off must be defined for each individual disease. In order to standardize current cytogenetic practices and apply a single denomination, we suggest defining a low complex karyotype as having 3 CAs, an intermediate complex karyotype as having 4 CAs, and a highly complex karyotype as having 5 or more CAs.

[HFE hemochromatosis: pathogenic and diagnostic approach]. / Hémochromatose HFE: approche pathogénique et diagnostique.

HFE hemochromatosis is the most frequent genetic iron overload disease. It is linked to the C282Y mutation of the HFE protein, protein encoded by the HFE gene, which is located on chromosome 6. The mechanisms accounting for iron excess are not only digestive hyperabsorption of iron but also excessive recycling of macrophagic iron coming from erythrophagocytosis and secreted into the blood. Both mechanisms are linked to an HFE-related hepatic failure in producing hepcidin, a key hormone of body iron regulation. The marked phenotypic variability of C282Y homozygosity expression is likely related to both genetic and environmental factors. The HFE gene discovery has rendered non invasive the positive diagnostic of HFE hemochromatosis, which is now based first on an increased level of plasma transferrin saturation leading to the request of the HFE mutation. Then, hepatic MRI is a reliable method to quantify iron overload. The HFE gene discovery has also paved the road of an enlarged field of differential diagnoses corresponding to novel entities of non-HFE related genetic iron overload syndromes.