The majority of the 13 mutations (12 missense and 1 splice site mutation) reported in ADC and 8 mutations (6 missense, 1 splice site and 1 nonsense mutations) in SCC are found in regions encoding functional domains involved in DNA binding (HIRAN domain), Sp1/Sp3 interaction (carboxyl-terminal domain), and DNA repair (SNF2_N/helicase-ATPase and RING finger domains) (Fig. 2). Here, SP3 is linked to AIDS dementia complex.