Glioblastoma and Colorectal Adenocarcinoma in an Adolescent Girl with Constitutional Mismatch Repair Deficiency Syndrome Mimicking Neurofibromatosis Type-I

Mismatch repair deficiency syndrome

Abstract

Children with constitutional mismatch repair deficiency syndrome (CMMRDS) are prone to different types of cancers. A 16-year-old girl who was misdiagnosed with neurofibromatosis Type-I (NF-I) for 1 years had experienced glioblastoma and colonic adenocarcinoma. After operation, chemotherapy and radiotherapy were started for adenocarcinoma. Genetic analysis from the patient, effected brother, and mother showed heterozygote (c.479 + 36A> G) mutation in the intron 4 region of NF-1 gene. Initially, it was thought that this genetic variant was causative. Furthermore, next generation sequencing showed that the index patient and his brother have homozygote (c.1444 C>T) mutations in the MSH6 gene which are associated with CMMRDS both died because of colonic adenocarcinoma, and T cell non-Hodgkin lymphoma, respectively. Patients with CMMRDS may resemble NF-I. The physicians must not be confused with the previous diagnosis. Increased awareness of CMMRDS, and prompt evaluation for an underlying genetic background is advised if there are unexpected cancer in patients with NF-I.