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.