Diagnosis of two cases from one family with Joubert syndrome caused by novel mutations of TCTN1 gene by whole exome sequencing / 中华医学遗传学杂志

OBJECTIVE@#To explore the pathogenesis of two fetuses from one family affected with Joubert syndrome (JS).@*METHODS@#Whole exome sequencing was employed to screen potential mutations in both fetuses. Suspected mutations were verified by Sanger sequencing. Impact of intronic mutations on DNA transcription was validated by cDNA analysis.@*RESULTS@#Two novel TCTN1 mutations, c.342-8A>G and c.1494+1G>A, were identified in exons 2 and 12, respectively.cDNA analysis confirmed the pathogenic nature of both mutations with interference of normal splicing resulting in production of truncated proteins.@*CONCLUSION@#The genetic etiology of the family affected with JS has been identified.Above findings have enriched the mutation spectrum of TCTN1gene and facilitated understanding of the genotype-phenotype correlation of JS.

Diagnostic follow-up for a case of mosaic trisomy 22 by non-invasive prenatal testing / 中华检验医学杂志

Objective To estimate prenatal diagnoses strategy with abnormal results of non-invasive prenatal testing (NIPT) based on a case of mosaic for trisomy 22.Methods The pregnanct woman was recruited from Department of Prenatal Diagnosis Center of Xinhua Hospital.Ultrasound scans suggested fetal nuchal translucency was 3.5 mm.Peripheral venous blood was drawn from the pregnant woman for NIPT at 12+2 weeks gestation.For further prenatal diagnosis, amniocentesis was conducted at 16+2 weeks gestation, and karyotype analysis combination with chromosome microarray analysis (CMA) was executed to analysis amniocytes.Results NIPT results suggested that chromosome 21, 18 and 13 were normal and supplementary reports suggested that chromosome 22 were slightly above the normal range.Karyotype analyzed 35 cultured cells.Each of them revealed a normal female karyotype.However, CMA results suggested that chromosome 22 gain mosaic and its copy number was 2.26.The fetus was diagnosed as high possibility of mosaic for trisomy 22.Conclusions Combined with the NIPT results, which was slightly gain mosaic of chromosome 22, a prenatal diagnosis strategy were proposed.When NIPT results suggest chromosomal abnormities, karyotype analysis combination with CMA to diagnose were recommended.