Clinical Research Directory

Modifying Factors in Striated Muscle Laminopathies

Mutations in the LMNA gene, which codes for lamins A and C, proteins of the nuclear lamina, are responsible for a wide spectrum of pathologies, including a group specifically affecting striated skeletal and cardiac muscles, with cardiac involvement being life-threatening. At the skeletal muscle level, a wide phenotypic spectrum has been described, ranging from severe forms of congenital muscular dystrophy to less severe forms of limb-girdle muscular dystrophy. The great clinical variability of striated muscle laminopathies, both inter- and intra-familial, can be observed in the age of onset, severity of signs and progression of muscle and heart involvement. To date, more than 400 LMNA mutations have been associated with striated muscle laminopathies (www.umd.be/LMNA/), highlighting strong clinical and genetic heterogeneity. A few recurrent mutations linked to a difference in severity have been identified. However, these genotype-phenotype relationships and the rare cases of digenism reported do not explain all the clinical variability of laminopathies. Therefore, there are probably other factors of severity than the causative mutation, called "modifier genes". Identification of such modifier genes has been initiated by studying a large family with significant clinical variability in the age of onset of muscle signs. A segregation analysis within this family identified 2 potential modifier loci. High-throughput sequencing restricted to these 2 regions according to phenotypic subgroups did not led to meaningful results so far. In addition, an international retrospective study of the natural history of early muscle laminopathies has allowed the investigators to highlight a strong inter-family clinical variability in patients carrying recurrent mutations. The investigators thus have strong preliminary data that could allow them to identify modifying genetic factors in a cohort of patients carrying a mutation in the LMNA gene. In order to identify these factors that modulate the clinical severity of laminopathies, the investigators wish to collect biological material (muscle and/or skin biopsies) from patients carrying a mutation in the LMNA gene. The study of this biological material using multi OMICs technics will allow the investigators to identify and functionally validate the action of these modifying genes. OMIICs is a set of techniques for characterising biological molecules using high-throughput approaches such as DNA sequencing, RNA sequencing and/or chromatin conformation (ATACseq...), proteins.

Observatoire Des Patients Atteints de Laminopathies et Emerinopathies (Observatory for PAtients With Laminopathies and Emerinopathies)

Laminopathies and emerinopathies are complex group of rare disorders due to mutations in A-type lamins (LMNA) and Emerin (EMD) genes. Among them, disorders affecting skeletal and/or cardiac muscles are the most frequent clinical manifestations, with cardiac disease being a major cause of death. Remarkable progress has been made in the description of the clinical and genetic spectrum of these diseases since the 1990's. Until now, precise phenotype/genotype relations remain elusive. As for several other neuromuscular disorders, apart from symptomatic treatments, there is currently no specific treatment to prevent or slow down the progression of the disease. The OPALE registry is a multicentre web-based registry dedicated to laminopathy and emerinopathy French patients. OPALE has been approved by ethical and regulatory authorities. Its main inclusion criteria is the presence of a proven pathogenic LMNA and/or EMD gene mutation. The OPALE objectives are to provide a tool allowing detailed capture of patient genetic, neurological, cardiological, endocrinological and respiratory assessments, in order to allow i) precise disease natural history, ii) evaluation of different disease complication frequency and iii) identification of prognosis factors.

Characterization of Patients With Cardiomyopathy to Identify Critical Patients Candidates for Cardiac Transplantation

The study aims to identify new diagnostic and prognostic markers for CMP that can help predict disease progression. In particular, the study will focus on microRNAs (miRNAs) and spatial transcriptomics, which are emerging techniques that may provide insights into the underlying disease mechanisms. By understanding these markers, the investigators hope to improve the way the investigators diagnose and manage CMP, particularly in terms of predicting progression to heart failure or heart transplantation. The study will evaluate patients with hypertrophic cardiomyopathy (e.g., sarcomeric forms, Anderson-Fabry disease, AL, and TTR cardiac amyloidosis), dilated cardiomyopathy and arrhythmogenic cardiomyopathy. These patients will undergo clinical evaluations, including ECG, echocardiograms, CMR, biopsy analysis, and genetic testing, as well as molecular studies such as transcriptomics and miRNA analysis. This comprehensive approach aims to identify potential new biomarkers for diagnosing and predicting the disease course.