The five known gene fusion partners of TFE3 are papillary 1 renal cell carcinoma (PRCC), alveolar soft part sarcoma locus (ASPL), polypyrimidine tract-binding protein-associated splicing factor (PSF), non-POU domain-containing octamer-binding (NonO, p54nrb), and clathrin heavy chain (CLTC) genes, situated on chromosome loci 1q21 [2–5], 17q25 [6–8], 1p34 [9], Xq12 [9], and 17q23 [10] respectively. The gene discussed is CLTC; the disease is renal cell carcinoma, Xp11-associated.