PAX1 in the thymus
Severe combined immunodeficiency (SCID) encompasses a wide spectrum of genetic disorders. Here, Yamazaki et al. have studied immune deficits in six patients with otofaciocervical syndrome type 2, a genetic abnormality attributed to biallelic mutations in PAX1. In addition to immunodeficiency, the disease is also characterized by facial dysmorphism, hearing loss and skeletal abnormalities. The patients were subjected to hematopoietic stem cell transplantation to rectify their immunodeficiency. Despite successful engraftment in three of these patients, all three of them failed to develop T cells. By generating patient-derived induced pluripotent stem cells and differentiating then ex vivo into thymic epithelial progenitors (TEPs), the authors find that PAX1 plays an important role in regulating the development of TEPs.
