Genetic analysis of a child with Pitt-Hopkins syndrome due to a novel variant of TCF4 gene derived from low percentage maternal mosaicism / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic etiology of a child with Pitt-Hopkins syndrome.@*METHODS@#A child who had presented at the Medical Genetics Center of Gansu Provincial Maternal and Child Health Care Hospital on February 24, 2021 and his parents were selected as the study subjects. Clinical data of the child was collected. Genomic DNA was extracted from peripheral blood samples of the child and his parents and subjected to trio-whole exome sequencing (trio-WES). Candidate variant was verified by Sanger sequencing. Karyotype analysis was also carried out for the child, and her mother was subjected to ultra-deep sequencing and prenatal diagnosis upon her subsequent pregnancy.@*RESULTS@#The clinical manifestations of the proband included facial dysmorphism, Simian crease, and mental retardation. Genetic testing revealed that he has carried a heterozygous c.1762C>T (p.Arg588Cys) variant of the TCF4 gene, for which both parents had a wild-type. The variant was unreported previously and was rated as likely pathogenic based on the guidelines of the American College of Medical Genetics and Genomics (ACMG). Ultra-deep sequencing indicated that the variant has a proportion of 2.63% in the mother, suggesting the presence of low percentage mosaicism. Prenatal diagnosis of amniotic fluid sample suggested that the fetus did not carry the same variant.@*CONCLUSION@#The heterozygous c.1762C>T variant of the TCF4 gene probably underlay the disease in this child and has derived from the low percentage mosaicism in his mother.

Optimizations of an ELISA-like high-throughput screening assay for the discovery of β-catenin/TCF4 interaction antagonists / 生物工程学报

In canonical Wnt/β-catenin signaling pathway, β-catenin/TCF4 (T-cell factor 4) interaction plays an important role in the pathogenesis and development of non-small cell lung cancer (NSCLC), and it is tightly associated with the proliferation, chemoresistance, recurrence and metastasis of NSCLC. Therefore, suppressing β-catenin/TCF4 interaction in Wnt/β-catenin signaling pathway would be a new therapeutic avenue against NSCLC metastasis. In this study, considering the principle of enzyme-linked immunosorbent assay (ELISA), an optimized high-throughput screening (HTS) assay was developed for the discovery of β-catenin/TCF4 interaction antagonists. Subsequently, this ELISA-like screening assay was performed using 2 μg/mL GST-TCF4 βBD and 0.5 μg/mL β-catenin, then a high Z' factor of 0.83 was achieved. A pilot screening of a natural product library using this ELISA-like screening assay identified plumbagin as a potential β-catenin/TCF4 interaction antagonist. Plumbagin remarkably inhibited the proliferation of A549, H1299, MCF7 and SW480 cell lines. More importantly, plumbagin significantly suppressed the β-catenin-responsive transcription in TOPFlash assay. In short, this newly developed ELISA-like screening assay will be vital for the rapid screening of novel Wnt inhibitors targeting β-catenin/TCF4 interaction, and this interaction is a potential anticancer target of plumbagin in vitro.

Genetic analysis of a case with Pitt-Hopkins syndrome due to variant of TCF4 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis of a patient presenting with dysmorphism, intellectual disability, psychomotor delay and hypoplasia of corpus callosum by using next generation sequencing.@*METHODS@#Genomic DNA was extracted from peripheral blood samples of the patient and his family members and subjected to exome sequencing. Suspected variants were verified with Sanger sequencing.@*RESULTS@#The patient was found to carry a heterozygous c.1357delAinsGGA variant in exon 11 of the TCF4 gene, which was verified as de novo by Sanger sequencing. The variant may result in a truncated protein and affect its function.@*CONCLUSION@#The heterozygous c.1357delAinsGGA variant the TCF4 gene probably underlies the disease in the proband.