Germline mismatch repair gene mutations in children with tumors: a case series from two centers

More than half of CMMRD syndrome and LS patients have no family history of cancer; thus, the absence of a positive family history does not rule out CMMRD syndrome and LS. A better diagnostic approach is to perform genetic testing to rule out the risk as early as possible when a newborn presents with cafe-au-lait spots, which are a typical feature of hereditary syndromes. Therefore, it is important to use germline genetic testing, combined with clinical phenotypic observation, to establish a diagnosis of a cancer susceptibility syndrome caused by an MMR gene mutation.