Analysis of a patient with tuberous sclerosis complex due to mosaicism TSC2 mutation / 中华医学遗传学杂志

OBJECTIVE@#To analyze variants of TSC1 and TSC2 genes in a Chinese patient with tuberous sclerosis complex (TSC).@*METHODS@#Peripheral blood samples were collected from the patient and her parents with informed consent. Following extraction of genomic DNA, potential variants of the TSC1 and TSC2 genes was detected by using targeted capture next-generation sequencing (NGS) and Sanger sequencing.@*RESULTS@#The patient was found to harbor a de novo mosaicism variant c.3295_3298delG (Val1100CysfsTer3) of the TSC2 gene, with the proportion of the mutant allele determined as 13.4%, which was confirmed by Sanger sequencing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c.3295_3298delG (Val1100CysfsTer3) variant was predicted to be pathogenic (PVS1+PS2+PM2).@*CONCLUSION@#The mosaicism heterozygous variant of c.3295_3298delG of the TSC2 gene, as detected by both NGS and Sanger sequencing, probably underlay the TSC2 in this patient.

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.

Genetic screening and prenatal diagnosis in high-risk families with tuberous sclerosis complex syndrome / 中华医学遗传学杂志

OBJECTIVE@#To carry out genetic testing and prenatal diagnosis for 29 Chinese pedigrees affected with tuberous sclerosis complex (TSC) and assess efficacy of combined next generation sequencing (NGS) and multiple ligation-dependent probe amplification (MLPA) for the diagnosis.@*METHODS@#NGS and MLPA were used in conjunct to detect variants of TSC1 and TSC2 genes among the probands of the pedigrees. Paternity test was carried out to exclude maternal DNA contamination. Prenatal diagnosis was provided to 14 couples based on the discoveries in the probands.@*RESULTS@#Twenty-seven variants were identified in the TSC1 and TSC2 genes among the 29 pedigrees, which yielded a detection rate of 93.1%. Respectively, 5 (18.5%) and 22 (81.5%) variants were identified in the TSC1 and TSC2 genes. Twelve variants were unreported previously. Prenatal diagnosis showed that five fetuses were affected with TSC, whilst the remaining nine were unaffected.@*CONCLUSION@#Above finding has expanded the spectrum of TSC1 and TSC2 gene variants. Combined NGS and MLPA has enabled diagnosis of TSC with efficiency and accuracy.