Identification of TSC2 mosaic mutation limited to cortical tuber with TSC targeted sequencing: a case report and literature review.

BACKGROUND Tuberous sclerosis complex (TSC) is an autosomal dominant disorder, mainly in childhood presents epilepsy due to cortical tubers. TSC1/TSC2 pathogenic variants cannot be detected in regular molecular genetic testing in around 10-15% of TSC patients. METHODS We analyzed TSC genes in both cortical tuber, blood and skin samples from a pediatric patient with refractory epilepsy. RESULTS We found no germline mutations by whole-exome sequencing. Well in targeted sequencing of TSC1/2 data, we identified de novo mutations only in cortical tuber: TSC2 NM_000548.5: exon34:c.4183C>T (p.Gln1395*) in 3% of the alleles. No other TSC mutations were found in patient's blood and skin samples and her parents' blood sample. CONCLUSION Our case report found TSC2 mosaic mutations can be only limited to cortical tuber in patients with TSC.