La maladie de Charcot-Marie-Tooth (CMT) est une pathologie neurologique affectant le système nerveux périphérique. Bien que décrite à la fin du XIXème siècle, la découverte d’une anomalie génétique n’a été identifiée chez ces patients que dans les années 1990 (duplication du gène PMP22). Depuis, de nombreux gènes ont été incriminés, et leur nombre ne cesse d’augmenter. Ainsi, cette multitude de gènes nous incite à rechercher des corrélations phénotype-génotype qui permettent d’orienter au mieux le diagnostic et la prise en charge de ces patients. Comme nous le montrons au travers de nos travaux, il est possible de s’appuyer sur des données cliniques, biologiques, électrophysiologiques (voire radiologiques) et histo-pathologiques (biopsie de nerf) pour orienter la recherche d’anomalies génétiques. Pour illustrer ceci, nous nous sommes appuyés sur l’exemple des mutations du gène INF2, gène récemment associé à la maladie de Charcot-Marie-Tooth. Dans ce cas précis, l’atteinte rénale, le profil électrophysiologique (forme « intermédiaire » de CMT) et surtout les données histo-pathologiques (la biopsie de nerf permettant de retrouver la présence d’expansions schwanniennes caractéristiques) sont évocatrices de la présence d’une anomalie portée par ce gène. D’autres exemples de corrélations génotype-phénotype sont apportés au travers d’observations. / Charcot-Marie-Tooth disease (CMT) is a neurological disorder of the peripheral nervous system. Even if it was described in the end of the nineteenth century, the first genetic abnormality (PMP22 duplication) was found only in the end of the twentieth century. Several other genes were found to be associated with this disease. This important number of potential genes leads us to find genotype-phenotype correlations in order to better and earlier diagnose these patients. As we can show it in our work, it is possible to use biological, electrophysiological (sometimes radiological) and pathological (nerve biopsy) in order to direct the genetic analysis towards the incriminated gene. To illustrate this, we have particularly study the INF2 gene, a gene recently associated with CMT. In this example, clinical (CMT phenotype and renal failure), electrophysiological (intermediate form of CMT), and pathological (supernumerary extensions of Schwann cells cytoplasm) features call to mind mutations in the INF2 gene. Other examples of genotype-phenotype correlations associated with various genes are reported in this manuscript.

Nephrotic syndrome is characterized by proteinuria, hypoproteinemia, edemas and hyperlipidemia. It occurs in primary (e.g. focal segmental glomerulosclerosis, FSGS or minimal change disease, MCD) and in secondary glomerulopathies (e.g. kidney amyloidosis). In primary forms, great attention is paid to the potential genetic background of the disease and due to new molecular genetic methods genes, whose mutations cause different nephropathies (e.g. ACTN4 or INF2) were identified. The aims of presented doctoral thesis were following. Firstly, to continue the mutational analysis of ACTN4 that was described in the author's diploma thesis in other glomerulopathies. Secondly, to implement the mutational analysis of INF2 and subsequently analyse this gene in patients with FSGS/MCD and in patients from special group characterized by positive family history for end stage renal disease (ESRD) in combination with advanced chronic kidney disease (CKD) or already developed ESRD at the time of diagnosis. Thirdly, mutational analysis of NPHS2 and TRPC6 (methods implemented in laboratory earlier) in selected patients from the special group. Finally, expression analyses of genes important for podocyte function or connected with human immune system. This part also verifies the applicability of NPHS2/SYNPO expression...