Enterokinase deficiency with novel TMPRSS15 gene mutation masquerading as acrodermatitis enteropathica

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.