Sideroblastic anemia, immunodeficiency, periodic fevers, and developmental delay (SIFD) is an autosomal recessive syndrome caused by biallelic loss-of-function variant of tRNA nucleotidyl transferase 1 (TRNT1). The gene discussed is TRNT1; the disease is congenital sideroblastic anemia-B-cell immunodeficiency-periodic fever-developmental delay syndrome.