Establishment of next-generation sequencing (NGS)-based genetic testing for tuberous sclerosis complex (TSC)

• Main Authors: Tsai-Tzu Wu, 吳采姿
• Other Authors: Pei-Lung Chen
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/74792819181891655423

碩士 === 國立臺灣大學 === 分子醫學研究所 === 102 === 　　Tuberous Sclerosis Complex (TSC) is an autosomal dominant genetic disorder. One third of patients are familial cases and two thirds are sporadic cases caused by de novo mutations. The disease is estimated to occur in 1:6000 live births worldwide with nearly equal distribution between females and males. TSC is a genetic multisystem disorder characterized by widespread hamartomas in several organs, including the brain, heart, skin, eyes, kidney, lung, and liver, etc. The clinical manifestations are highly variable, and might include epilepsy, mental retardation, behavioral problems, skin lesions and renal problems, which often cause harm to patients physically and psychologically. The only two known disease-causing genes are TSC1 and TSC2, encoding hamartin and tuberin respectively. The hamartin-tuberin complex inhibits the mammalian　target　of　 rapamycin (mTOR) pathway, which controls cell growth, cell proliferation and several other important functions. 　　In this current study, we applied the next-generation sequencing (NGS) technology for the TSC1 and TSC2 genes. Among the 94 patients with definite TSC diagnosis, we could identify the causative genetic variants for 78 cases. There were 16 cases with no mutation identified. In 78 cases, 50 cases had point mutation, 20 cases had small deletion or insertion (indel) and 8 cases had large deletion or duplication. Our overall detection rate using NGS were 81% (76/94). Among the detected disease-causing variants, large deletion or insertion accounted for approximately 10% (8/76). NGS and Sanger sequencing are equally good at detecting point mutations and small indels. Besides, NGS could be more sensitive to detect mosaic variant. Furthermore, it is possible to clearly detect the breakpoints of large deletion or insertion through Integrative Genomics Viewer (IGV) using NGS reads. In conclusion, NGS can replace traditional genetic testing methods, and serve as cost-effective, sensitive and reliable genetic testing platform for TSC.