COL4A5 and lymphangioma: High-throughput sequencing analysis uncovered different gene mutations in LM, including mediator complex subunit 12 (MED12) gene mutation (mut-MED12), high mobility group AT-hook 2 (HMGA2) translocations, biallelic loss of fumarate hydratase (FH), collagen (COL4A5–COL4A6) gene deletions, and germline mutations in the SRCAP members YEATS4 and ZNHIT1 (14, 15), with mut-MED12 contributing to approximately 70% of all LM (16).