Severe combined immunodeficiency due to FOXN1 deficiency

A rare, genetic, primary immunodeficiency due to a defect in adaptive immunity characterized by the triad of congenital athymia (resulting in severe T-cell immunodeficiency), congenital alopecia totalis and nail dystrophy. Patients present neonatal or infantile-onset, severe, recurrent, life-threatening infections and low or absent circulating T cells. Additional features reported include erythroderma, lymphoadenopathy, diarrhea and failure to thrive.