MED12 and hereditary leiomyomatosis and renal cell cancer: Structural variants in MED12 and HMGA1 were also common in HLRCC patients with a subset (cases 1796, 1802 and 1687) exhibiting duplications or inversions in Collagen Type IV Alpha 5 Chain (COL4A5) and collagen type IV alpha 6 chain (COL4A6).