The FOXN1 leads to congenital alopecia and an alymphoid thymus with severe combined primary T-cell immunodeficiency,7,44, 45, 46 resulting in death in early childhood from severe infections.44,47 Therefore, gene therapy with FOXN1 is one of options to be possibly selected to treat fetal FOXN1 mutations. This evidence concerns the gene FOXN1 and T-cell immunodeficiency.