A case of tuberous sclerosis complex due to a novel splicing variant of TSC2 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a patient with tuberous sclerosis complex.@*METHODS@#Genomic DNA was extracted from peripheral blood samples from members of his family and 100 unrelated healthy controls. The proband was subjected to next-generation sequencing, and candidate variant was confirmed by multiple ligation-dependent probe amplification (MLPA) and Sanger sequencing. Reverse transcription-PCR (RT-PCR) was carried out to determine the relative mRNA expression in the proband.@*RESULTS@#The patient was found to harbor a c.2355+1G>C splicing variant of the TSC2 gene. Sequencing of cDNA confirmed that 62 bases have been inserted into the 3' end of exon 21, which has caused a frameshift producing a truncated protein.@*CONCLUSION@#The novel splicing variant c.2355+1G>C of the TSC2 gene probably underlay the TSC in the proband. Above finding has expanded the variant spectrum of TSC2 and provided a basis for preimplantation genetic testing and/or prenatal diagnosis.

Molecular machine and gold/graphene quantum dot hybrid based dual amplification strategy for voltammetric detection of VEGF165.

Graphene quantum dots (GQDs) were prepared via pyrolysis of citric acid and glutamic acid, then reacted with chlorauric acid to form a gold/graphene quantum dot hybrid (Au/GQD), and finally connected with hairpin DNA probe 1 (H1) and thionine (Thi). The H1-Au/GQD-Thi composite is found to be a viable redox probe for electrochemical and aptamer-based determination of vascular endothelial growth factor VEGF165. A dual amplification strategy is employed based on the use of molecular machine and the Au/GQD. Each single VEGF165 molecule can bind two DNA probes via specific aptamer-target recognition to produce a molecular machine. Surface-tethered hairpin DNA 2 (H2) hybridizes with the molecular machine through proximity effect, and the prelocked toehold domain of H2 becomes exposed. This part binds to H1-Au/GQD-Thi to release the molecular machine which then moves to the neighboring H2 upon which a surface programmatic chain reaction is initiated. By continuous molecular machine travel, many H1-Au/GQD-Thi probes are present on the gold electrode surface. This implies an efficient signal amplification capability. The Au/GQD based redox probes in-situ catalyzes the redox activity of thionine and further enhances the detection signal. The aptasensor exhibits ultrahigh sensitivity and selectivity for VEGF165. The square wave voltammetric signal, best measured at -0.18 V vs. Ag/AgCl, increases linearly in the 1.0 fM to 120 pM VEGF165 concentration range, and the detection limit is 0.3 fM. Conceivably, the method may be applied to other target proteins if the corresponding high-affinity aptamers are available. Graphical abstract This study report one dual amplification strategy for ultrasensitive electrochemical detection of VEGF165 based on gold-graphene quantum dot hybrid (Au/GQD) and bipedal molecular machine (BMM) powered surface programmatic chain reaction (SPCR).