Enterokinase deficiency with novel TMPRSS15 gene mutation masquerading as acrodermatitis enteropathica

Abstract Enterokinase deficiency (EKD) is a rare autosomal recessive inherited disorder caused by loss‐of‐function mutations of the transmembrane protease serine 15 ( TMPRSS15 ) gene. To date, only 12 cases of EKD have been described in the literature and skin involvement has seldom been described. We identified a novel homozygous nonsense mutation in the TMPRSS15 gene (c.1216C>T, p.R406*) in a female infant, who manifested with acrodermatitis enteropathica (AE)‐like lesions that were dramatically relieved within 11 days after initiation of a protein‐rich hydrolyzed formula. Our case shows that AE‐like rashes can be a manifestation of EKD and expands the spectrum of causative mutations in the TMPRSS15 gene.