TRNT1 and Global developmental delay: We recently described a cohort of patients with congenital sideroblastic anemia with B-cell immunodeficiency, periodic fevers and developmental delay (SIFD) [2] due to mutations in TRNT1. We demonstrated that patient mutations result in an impairment of TRNT1 to catalyze the addition of CCA to tRNA, while the knockdown of TRNT1 results in significant cytotoxicity and apoptosis.