First Korean case of a STAT1 gene mutation: chronic mucocutaneous candidiasis, hypothyroidism, chronic hepatitis and systemic lupus erythematosus

Abstract

Chronic mucocutaneous candidiasis (CMC) is characterized by increased susceptibility to chronic and recurrent infections of the skin, mucous membranes, and nails by Candida species. It is a primary immunodeἀciency disorder that is difἀcult to di-agnose because of its heterogeneous clinical manifestations and genetic background. A 20-month-old boy who did not grow in height for 3 months was diagnosed as having hypothyroidism and he had hepatitis which was found at 5 years old. He pre-sented with persistent oral thrush and vesicles on the body, the cause of which could not be identiἀed from laboratory ἀnd-ings. No microorganism was detected in the throat culture; however, the oral thrush persisted. Immunological tests showed that immunoglobulin (Ig) subclass IgG and cluster of differentiation (CD)3, CD4, and CD8 levels were within normal limits. We prescribed oral levothyroxine and Ḁuconazole mouth rinse. The patient was examined using diagnostic exome sequenc-ing at the age of 6 years, and a c.1162A>G (p.K388E) STAT1 gene mutation was identiἀed. A diagnosis of CMC based on the STAT1 gene mutation was, thus, made. At the age of 8 years, the boy developed a malar-like rash on his face. We conducted tests for detection of antinuclear antibodies and anti-dsDNA antibodies, which showed positive results; therefore, systemic lupus erythematosus (SLE) was also suspected. Whole exome sequencing is important to diagnose rare diseases in children. A STAT1 gene mutation should be suspected in patients with chronic fungal infections with a thyroid disease and/or SLE.