However, 10 to 15% of TSC patients have no mutation identified (NMI), despite thorough molecular diagnostic testing, including exon-based Sanger sequencing and analysis for large genomic deletions in TSC1 and TSC2. NMI TSC subjects generally have milder clinical features of TSC than patients with identified TSC2 mutations [10,15,21,22]. Here, TSC1 is linked to tuberous sclerosis.