Somatic Mutations in TSC1 and TSC2 Cause Focal Cortical Dysplasia.
Focal cortical dysplasia (FCD) is a major cause of the sporadic form of intractable focal epilepsies that require surgical treatment. It has recently been reported that brain somatic mutations in MTOR account for 15%-25% of FCD type II (FCDII), characterized by cortical dyslamination and dysmorphic neurons. However, the genetic etiologies of FCDII-affected individuals who lack the MTOR mutation remain unclear. Here, we performed deep hybrid capture and amplicon sequencing (read depth of 100×-20,012×) of five important mTOR pathway genes-PIK3CA, PIK3R2, AKT3, TSC1, and TSC2-by using paired brain and saliva samples from 40 FCDII individuals negative for MTOR mutations. We found that 5 of 40 individuals (12.5%) had brain somatic mutations in TSC1 (c.64C>T [p.Arg22Trp] and c.610C>T [p.Arg204Cys]) and TSC2 (c.4639G>A [p.Val1547Ile]), and these results were reproducible on two different sequencing platforms. All identified mutations induced hyperactivation of the mTOR pathway by disrupting the formation or function of the TSC1-TSC2 complex. Furthermore, in utero CRISPR-Cas9-mediated genome editing of Tsc1 or Tsc2 induced the development of spontaneous behavioral seizures, as well as cytomegalic neurons and cortical dyslamination. These results show that brain somatic mutations in TSC1 and TSC2 cause FCD and that in utero application of the CRISPR-Cas9 system is useful for generating neurodevelopmental disease models of somatic mutations in the brain.
['Lim|Jae Seok|JS|', 'Gopalappa|Ramu|R|', 'Kim|Se Hoon|SH|', 'Ramakrishna|Suresh|S|', 'Lee|Minji|M|', 'Kim|Woo-Il|WI|', 'Kim|Junho|J|', 'Park|Sang Min|SM|', 'Lee|Junehawk|J|', 'Oh|Jung-Hwa|JH|', 'Kim|Heung Dong|HD|', 'Park|Chang-Hwan|CH|', 'Lee|Joon Soo|JS|', 'Kim|Sangwoo|S|', 'Kim|Dong Seok|DS|', 'Han|Jung Min|JM|', 'Kang|Hoon-Chul|HC|', 'Kim|Hyongbum Henry|HH|', 'Lee|Jeong Ho|JH|']
D000293:Adolescent D000818:Animals D001921:Brain D064113:CRISPR-Cas Systems D045744:Cell Line, Tumor D002648:Child D058534:Class I Phosphatidylinositol 3-Kinases D003001:Cloning, Molecular D004195:Disease Models, Animal D004827:Epilepsy D005260:Female D057809:HEK293 Cells D006801:Humans D008297:Male D065703:Malformations of Cortical Development, Group I D051379:Mice D009154:Mutation D009474:Neurons D019869:Phosphatidylinositol 3-Kinases D051057:Proto-Oncogene Proteins c-akt D012463:Saliva D017422:Sequence Analysis, DNA D020123:Sirolimus D058570:TOR Serine-Threonine Kinases D000077004:Tuberous Sclerosis Complex 1 Protein D000077005:Tuberous Sclerosis Complex 2 Protein D025521:Tumor Suppressor Proteins
TSC1 TSC2 focal cortical dysplasia brain somatic mutation CRISPR-Cas9 genome editing brain mosaicism intractable epilepsy