KRIT1 and cerebral cavernous malformation: In Krit1/Ccm1 mouse mutant BMECs there was a significant downregulation of Slc39a4 and Slc39a8 transcripts (Fig. 6c), and a slight upregulation of Slc39a3. To determine if the transcriptional regulation of SLC39 zinc transporters is relevant to the pathology of CCM disease, we analyzed endothelial cell (EC) RNA from five human CCM lesions (four sporadic and one familial CCM1) and compared these samples to corresponding brain tissue from three patients free of neurological disease.