A missed opportunity for preventing CMMRD: is it time to include Lynch syndrome genes in prenatal genetic testing?

This manuscript highlights the importance of incorporating Lynch syndrome-related genes into prenatal genetic testing to facilitate early detection of constitutional mismatch repair deficiency syndrome (CMMRD). CMMRD, linked to biallelic pathogenic variants in mismatch repair genes, is an aggressive hereditary cancer syndrome. A couple conceived through in vitro fertilisation (IVF), unaware they were carriers of Lynch syndrome. Their child, initially healthy, was diagnosed with acute bilineal leukaemia and later found to have CMMRD. His diagnosis highlighted gaps in prenatal testing. Advances in next-generation sequencing enable broader genetic screening, offering parents crucial risk assessment tools, especially those undergoing IVF, to make informed reproductive choices.