SPOP is a protein that can modify other proteins through the attachment of so-called ubiquitin residues. This process is required for the clearence of proteins through an organelle called proteasome.
GoF mutations in SPOP (Arg121Gln and Asp144Asn) promote enhanced protein degradation of the BET proteins and possibly other proteins. Arg121Gln has been previously also described as an acquired and likely cancer-causing gene mutation in endometrial cancer (Janouskova, 2017).
However, no increased cancer risk for patients with NSDVS1 have been observed.
SPOP GoF