Facial Dysmorphism and Severe Vascular Phenotype in TRNT1 Deficiency with Concomitant Antithrombin III Deficiency

TRNT1 deficiency (SIFD syndrome) is a rare inborn error of immunity characterized by sideroblastic anemia, immunodeficiency, periodic fevers, and developmental delay. We report two Romanian patients with genetically confirmed TRNT1 deficiency presenting with characteristic hematologic and immunologic abnormalities and a distinctive facial dysmorphism. One patient additionally developed severe gastrointestinal ischemia and intracranial hemorrhage in the setting of concomitant hereditary antithrombin III deficiency. These observations expand the phenotypic spectrum associated with TRNT1 deficiency and highlight the marked clinical variability of this disorder. The contribution of TRNT1-associated inflammation to the vascular phenotype remains speculative and cannot be distinguished from the effects of the concomitant thrombophilic condition.