T-B- severe combined immunodeficiency (SCID) [9 genes]

This form of severe combined immunodeficiency (SCID) is characterized by a lack of functional peripheral T and B lymphocytes. In addition, these defects may be accompanied by absence of functional NK cells. SCID T-B- is mainly caused by alterations in genes involved in V(D)J recombination , a mechanism necessary to create the different repertoires of T cells and B cells.

• <1/1,000,000 individuals

• Differential diagnosis with BLS or agammaglobulinemia
• Genetic counseling
• Hematopoietic stem cell transplantation (HSCT)
• Gene therapy

Identifying a genetic defect responsible for the disease would allow a precise molecular diagnosis to be issued and make it possible to provide genetic counseling to the patient and their family members. In some cases, detecting a genetic variant can help explore specific treatment options.

In the case of severe combined immunodeficiencies, the treatment is usually bone marrow transplantation, but new emerging gene therapies open the door to other treatments that may be applied shortly.

• Severe life-threatening infections (viral, fungal, bacterial)
• Diarrhea
• Failure to thrive
• Autoimmunity
• Onset: neonatal, infancy