NCT03912129

Autoimmune Cytopenia: Genetics and Pathophysiological Mechanism in Pediatric Evans Syndrome

• Status: Unknown
• Phase: N/A
• Study type: Interventional
• Enrollment: 200 (estimated)
• Sponsor: University Hospital, Bordeaux · Academic / Other
• Sex: All
• Age: —
• Healthy volunteers: Not accepted

Summary

Characterization of the genetic causes, and of the immunopathological clinical and biological manifestations in children with pediatric Evans syndrome included in a prospective national observational cohort of rare diseases.

Detailed description

Pediatric Evans syndrome (pES) is a rare and severe disease combining immunologic thrombocytopenic purpura (ITP) and autoimmune hemolytic anemia (AIHA). French patients from the 30 hematologic pediatric centers are from 2004 included in a prospective national OBS'CEREVANCE cohort. A first pilot study revealed a monogenic cause in 7/18 patients (40%) with mutations in the CTLA-4, LRBA, STAT3 GOF, and KRAS. TNGS or exome studies were performed between 2015 and 2018 inn 80 patients with pSE from the OBS'CEREVANCE cohort. This approach, combined with by immunophenotyping lymphocyte, identified a genetic cause of the disease in 26 patients (32%) (TNFRSF6, CTLA4, LRBA, STAT3 GOF, PIK3CD, RAG1, KRAS) and potential causal mutations in 18 other patients (22%), bringing the proportion of potential single gene cause to 76%. The central hypothesis of this study is that most, if not all, cases of pSE are related to a monogenic or digenic cause, possibly with the intervention of genetic modifiers such as somatic mutations.

Conditions

• Evans Syndrome

Interventions

Type	Name	Description
GENETIC	blood sample	A first systematic approach by Targeted-Next Generation Sequencing will be used on the entire cohort of patients with pSE. This step will be performed on a sequencing chip specifically developed to detect anomalies in known genes involved in autoimmunity. In patients for whom no mutations are identified, a whole exome sequencing (WES) approach will be applied to patients and their parents to seek to identify mutations in new genes that may be related to pSE. In patients for whom this WES approach is unsuccessful, the search for somatic lymphocyte mutations, or copy number variants will be performed before considering a complete genome sequencing . If several candidate genes are identified, the clinical data provided by the CEREVANCE and the phenotypic analyses carried out prior to genetic analyses by the CEDI laboratory will guide the choices to prioritize the study of the identified variants.

Timeline

• Start date: 2019-05-06
• Primary completion: 2022-05-06
• Completion: 2022-05-06
• First posted: 2019-04-11
• Last updated: 2019-04-11