Late presentation of cancer in compound heterozygote PMS2 mutation carrier

Background Turcot syndrome is clinically characterized by the occurrence of primary brain tumors, colorectal cancer and/or accompanying adenomas. It has been described as both an autosomal dominant and recessive condition and mutations in APC, MLH1, MSH2, MSH6 and PMS2 have been reported. Constitutional Mismatch repair (CMMR) deficiency is a variant of Lynch syndrome (LS) associated with biallelic MMR mutations. Individuals present with NF1 manifestations and generally develop hematological malignancies, brain tumors and/or LS associated cancers, in the first or second decade of life. We report an individual with café au lait macules (CAL) and a history of glioblastoma at 31 and proximal colon cancer at 32. Family history includes a mother with hematologic cancers in her 60’s, maternal half uncle with colon cancer at 48, maternal half uncle with renal cancer and three maternal great uncles with colon cancer.