A case of a new Lynch Syndrome variant with a deletion, c.1024_1026, in the MSH2 gene in a Chinese family

Abstract

Background Multiple genetic variations have been identified in mismatch repair genes for Lynch Syndrome. However, diagnosis of Lynch Syndrome and its subtypes in patients with atypical cancer types still remains challenging. Little is known about Lynch syndrome-related renal carcinoma and related genes. We present a case of renal carcinoma with multiple primary skin tumors, with a new Lynch Syndrome variant with a deletion in a Chinese family. Case presentation: The patient was a 60-year-old Chinese male with a history of Lynch Syndrome-related renal carcinoma with repeatedly multiple primary skin tumors. Immunohistochemistry revealed loss of MSH2 and MSH6 proteins. Sequencing of mismatch repair genes revealed a previously unknown germline MSH2 mutation (c.1024_1026 del) resulting in an amino acid deletion (p. V342del). This variant was co-segregated among the carcinoma-affected family members. After 6 cycles of immunotherapy, a marked regression of the skin tumor was obtained. Conclusions We clarify the pathogenic significance of this new mutation and suggest immunotherapy for patients with this subtype of Lynch Syndrome.