Genetic Susceptibility to Severe Infections

Condition(s) studied

Investigational drug(s) / intervention(s)

Blood samples drawing: 10 ml of periferal blood

Skin biopsy: Skin biopsy only in some index cases depending of the pathology at the recruitment

Study summary

Only a fraction of individuals infected with microbes develop clinical disease. This observation raises fundamental questions about the pathogenesis of infectious diseases. There is a complex interaction between environmental (microbial and non-microbial) and human (genetic and non-genetic) factors. This will determine the quality of the immune response against the infectious agent and the clinical manifestation. By definition, individuals who die from an infection have defective immunity to the pathogen in question (immune agent (immune deficiency).

The investigation of individual variability in the development of infectious diseases began in the early 20th. The first evidence to support the hypothesis that individual variability variability and immune deficiencies were hereditary came from observations of familial cases or genetic isolates genetic isolates (from a homogeneous population) of rare or common infectious diseases, which in some cases Mendelian heredity hat predisposition to infectious diseases runs in families even more so than diseases associated with less determined environmental factors, such as certain cancers. such as certain cancers. Finally, studies comparing the rate of concordance of infectious diseases between monozygotic and dizygotic twins also implicate genetic factors in disease susceptibility.

These observations were validated by the discovery of genetic defects associated with severe infectious diseases, leading to proof of concept. While a number of hereditary immune deficiencies associated with susceptibility to multiple pathogens or microorganisms, a growing number of new and rare new and rare immune deficiencies conferring restricted susceptibility to infections caused by a single caused by a single pathogen family, or even a single pathogen, in otherwise healthy children, have recently been identified (one gene, one pathogen). As a result, a dozen Mendelian clinical syndromes characterized by restricted susceptibility are now known. Over the last 20 years, it has been proven that these "idiopathic" infections were immune deficiencies.

The investigators now wish to study new severe infections, including but not limited to viral, fungal and bacterial infections. viral, fungal, bacterial and parasitic infections. This should lead to a better understanding of the pathophysiology of each disease, the development of new therapeutics and better patient care.

Eligibility

Primary outcome measure(s)

• Identification of chromosomal regions associated with the disease through a "homozygosity mapping" study on multiplex and/or consanguineous families. — through study completion, an average of 10 years
  Whole genome genotyping using high density microarrays (Affymetrix 6.0 type or equivalent) on the gDNA of the index case and its relatives. Exome data will also be used for homozygosity calculation.
• Identification of candidate genes for genetic susceptibility to infectious diseases — through study completion, an average of 10 years
  1. To sequence using the high-throughput sequencing technique (exome or genome). 2. To check the genetic segregation of mutations identified in relatives in each family.
• Validation of candidate genes as factor of susceptibility to infectious diseases — through study completion, an average of 10 years
  To validate the pathogenic effect of the mutation by functional and complementation tests on patient cells and control cells, and in an overexpression system

Trial sites (1)

More Institut National de la Santé Et de la Recherche Médicale, France trials in France

Other trials for the same condition