Lynch syndrome-associated repeated stroke with MLH1 frame-shift mutation

Lynch syndrome (LS) is an autosomal dominant inherited disease caused by germline mutations in DNA mismatch repair (MMR) genes, including MLH1, MSH2, MSH6, and PMS2, which predisposes patients to various malignant neoplasms. Previous studies showed that MLH1, MSH2, MSH6, and PMS2 mutation in LS were associated with an elevated risk of colorectal, gastric, endometria, ovarian, and other cancers among family members. Patients of these kinds of cancers had high incidence of synchronous and metasynchronus. We describe the case of a 34-year-old female patient with 50 days of sudden dizziness and left limb weakness, whose head CT scan showed large infarction in the right frontal temporal parietal lobe and basal ganglia area. Imaging examinations and pathological biopsy indicated high-grade serous carcinoma (HGSC) IIIA1 of the right ovary. In addition, a novel frame-shift mutation in the MLH1 gene (c.1621dupG, p.A541Gfs*16) was found in the genetic panel sequence. It may render declining of MLH1 protein and also associate with the patient's progressive clinical manifestations of multiple systems. Therefore, the timely use of prenatal diagnosis to prevent unnecessary new cases of this severe genetic disease is available.