Constitutional mismatch repair deficiency (CMMRD) syndrome is a rare genetic disorder that significantly elevates the risk of developing various cancers in children and young adults. Early and accurate Cmmrd Diagnosis is crucial for timely intervention and management. The most frequent cancers associated with CMMRD syndrome include colorectal cancer, brain tumors, and blood cancers like leukemia and lymphoma.
Cancer development is almost universal in individuals with CMMRD syndrome before the age of 18, typically manifesting in late childhood. The age at diagnosis can vary depending on the specific type of cancer; brain cancers, leukemia, and lymphomas tend to appear at younger ages compared to colorectal cancer in those with CMMRD syndrome. Alarmingly, it is estimated that 20% to 40% of individuals with CMMRD syndrome who develop cancer will experience the development of a secondary cancer later in their lives.
Individuals with CMMRD syndrome are also prone to developing multiple noncancerous growths called adenomas in the colon. These adenomas have a high likelihood of progressing into malignant tumors over time. Brain cancers associated with CMMRD syndrome often involve glial cells, leading to the formation of gliomas or glioblastomas. Non-Hodgkin lymphoma, a cancer affecting white blood cells, is the most prevalent type of blood cancer in CMMRD syndrome. Other cancers that can occur in individuals with CMMRD syndrome include cancers of the small intestine, urinary tract, and endometrial cancer.
Many individuals with CMMRD syndrome exhibit characteristics similar to neurofibromatosis type 1, a separate genetic condition. These overlapping features include changes in skin pigmentation, most notably café-au-lait spots, which are flat patches of skin darker than the surrounding area. Some individuals may also present with freckling or hypopigmented skin patches that are unusually light. In rare cases, individuals with CMMRD syndrome may develop Lisch nodules, benign growths in the iris of the eye, another hallmark of neurofibromatosis type 1. It’s important to note that Lisch nodules do not impair vision. Due to these overlapping features, some individuals with CMMRD syndrome are initially misdiagnosed with neurofibromatosis type 1, highlighting the importance of accurate cmmrd diagnosis for appropriate management and genetic counseling.
