Patient 1: bi-allelic pathogenic PMS2 GVs
Patient 1 was diagnosed with T-lymphoblastic lymphoma (T-LL) at age three years, Burkitt Lymphoma at 14, and underwent proctocolectomy at 14 due to numerous colonic polyps. These three diagnoses prompted germline testing, which revealed bi-allelic pathogenic PMS2 variants, consistent with constitutional mismatch repair deficiency (CMMRD). At age 16, a changing mole on the right cheek was biopsied, diagnostic of MM, and treated with wide local excision (WLE). The patient expired a few months later secondary to relapsed T-LL. Cascade testing identified that one variant was maternally inherited while the patient’s father did not undergo testing. These results prompted Lynch Syndrome cancer screening for his family.