Ectodermal dysplasias are a heterogeneous group of disorders characterized by developmental dystrophies of ectodermal structures, including the skin, hair, nails, eccrine glands and teeth. Anhidrotic ectodermal dysplasia (AED) is the most common type and is usually inherited as an X-linked recessive trait. The gene responsible for the AED is ectodysplasin-A (EDA). AED is characterized by triad of signs which comprised of sparse hair, abnormal or missing teeth, and inability to sweat due to lack of sweat glands. Herein, we represent a case of AED in a 1 year-old Korean boy. The patient presented hypohidrosis, loose hair, absence of eyebrows and teeth hypodevelopment. Diagnostic exome sequencing identified a known mutation of the EDA gene (c. 463 C>T) (p. Arg 155 Cys), and this mutation was confirmed by Sanger sequencing. The deletion mutations were revealed in the gene analysis. The diagnosis of anhidrotic ectodermal dysplasia was made on the basis of the clinical features and gene analysis.