When NIPT meets WES, prenatal diagnosticians face the dilemma: genetic etiological analysis of 2,328 cases of NT thickening and follow-up of pregnancy outcomes.

Objective: To assess the performance of diverse prenatal diagnostic approaches for nuchal translucency (NT) thickening and to investigate the optimal prenatal screening or diagnostic action with a NT thickening of 95th percentile-3.50 mm. Methods: A retrospective analysis of 2,328 pregnancies with NT ≥ 95th percentile through ultrasound-guided transabdominal chorionic villus sampling (CVS), amniocentesis, or cordocentesis obtained clinical samples (chorionic villi, amniotic fluid, and cord blood), and real-time quantitative fluorescent PCR (QF-PCR), chromosome karyotyping (CS), chromosome microarray analysis (CMA), or whole exome sequencing (WES) were provided to identify genetic etiologies. Results: In this study, the incidence of chromosomal defects increased with NT thickness. When NT ≥ 6.5 mm, 71.43% were attributed to genetic abnormalities. The 994 gravidas with fetal NT thickening underwent short tandem repeat (STR), CS, and CMA. In 804 fetuses with normal karyotypes, CMA detected 16 (1.99%) extra pathogenic or likely pathogenic copy number variations (CNVs). The incremental yield of CMA was only 1.16% (3/229) and 3.37% (10/297) in the group with NT 95th percentile-2.99 mm and NT 3.0-3.49 mm, separately. Among the 525 gravidas with fetal NT thickening who underwent STR, CMA, and WES, the incremental yield of WES was 4.09% (21/513). In the group of NT 95th percentile-2.99 mm, there were no additional single-nucleotide variations (SNVs) detected in WES, while in 143 cases with NT of 3.0-3.49 mm, the incremental yield of WES was 5.59% (8/143). Conclusion: In the group of NT 95th percentile-3.0 mm, since chromosomal aneuploidy and chromosomal copy number variation were the primary causes and the additional contribution of CMA and WES was not significant, we recommend NIPT-Plus for pregnant women with a NT thickening of 95th percentile-3.0 mm first. In addition, comprehensive prenatal genetic testing involving CMA and WES can benefit pregnancies with NT thickening of 3.0-3.49 mm.

Novel Biallelic Variant in the BRAT1 Gene Caused Nonprogressive Cerebellar Ataxia Syndrome.

Recessive mutations in BRAT1 cause lethal neonatal rigidity and multifocal seizure syndrome (RMFSL), a phenotype characterized by neonatal microcephaly, hypertonia, and refractory epilepsy with premature death. Recently, attenuated disease variants have been described, suggesting that a wider clinical spectrum of BRAT1-associated neurodegeneration exists than was previously thought. Here, we reported a 10-year-old girl with severe intellectual disability, rigidity, ataxia or dyspraxia, and cerebellar atrophy on brain MRI; two BRAT1 variants in the trans configuration [c.1014A > C (p.Pro338 = ); c.706delC (p.Leu236Cysfs*5)] were detected using whole-exome sequencing. RNA-seq confirmed significantly decreased BRAT1 transcript levels in the presence of the variant; further, it revealed an intron retention between exon 7 and exon 8 caused by the synonymous base substitute. Subsequent prenatal diagnosis for these two variants guided the parents to reproduce. We expand the phenotypic spectrum of BRAT1-associated disorders by first reporting the pathogenic synonymous variant of the BRAT1 gene, resulting in clinical severity that is mild compared to the severe phenotype seen in RMFSL. Making an accurate diagnosis and prognostic evaluation of BRAT1-associated neurodegeneration is important for reproductive consultation and disease management.

A spectrum of clinical severity of recessive titinopathies in prenatal.

Variants in TTN are associated with a broad range of clinical phenotypes, from dominant adult-onset dilated cardiomyopathy to recessive infantile-onset myopathy. However, few foetal cases have been reported for multiple reasons. Next-generation sequencing has facilitated the prenatal identification of a growing number of suspected titinopathy variants. We investigated six affected foetuses from three families, completed the intrauterine course of the serial phenotypic spectrum of TTN, and discussed the genotype-phenotype correlations from a broader perspective. The recognizable prenatal feature onset at the second trimester was started with reduced movement, then contracture 3-6 weeks later, followed with/without hydrops, finally at late pregnancy was accompanied with polyhydramnio (major) or oligohydramnios. Two cases with typical arthrogryposis-hydrops sequences identified a meta-only transcript variant c.36203-1G>T. Deleterious transcriptional consequences of the substitution were verified by minigene splicing analysis. Case 3 identified a homozygous splicing variant in the constitutively expressed Z-disc. It presented a milder phenotype than expected, which was presumably saved by the isoform of corons. A summary of the foetal-onset titinopathy cases implied that variants in TTN present with a series of signs and a spectrum of clinical severity, which followed the dosage/positional effect; the meta-only transcript allele involvement may be a prerequisite for the development of fatal hydrops.

[Changes of transport sugar content in different organs of Rehmannia glutinosa].

Raffinose series oligosaccharides are the transport and storage sugars of many plants, Rehmannia glutinosa is one of the commonly used Chinese herbal medicines, medicinal parts ist he roots. Root and tuber of R. glutinosa contains stachyose, raffinose and other oligosaccharides, but the study about the process of growth and development of other organs in the non-structural changes in sugar content is rare.In this study, leaves, stems and roots of R. glutinosa were used as materials to analyze the diurnal variation and the changes of sugar content of sucrose, raffinose and stachyose in different organs of R. glutinosa. The results showed that the content of sucrose in R. glutinosa leaves gradually increased from seedling stage.However, the content of stachyose did not change much at the early stage of growth, and the stachyose rapidly increased at the later stage of growth. The raffinose content gradually decreased throughout the growing season, young leaves of R. glutinosa have higher ability to sucrose synthesis than mature leaves, while mature leaf has higher raffinose and stachyose synthesis ability than young leaves. Sucrose and stachyose content in stem gradually increased, while there was little change in raffinose content. The content of raffinose and stachyose in root increased rapidly from the beginning of fast growing period, while the content of sucrose did not change much. The content of sucrose in leaves of R. glutinosa did not change much at day and night, while the daily changes of raffinose and stachyose contents were very obvious. The contents of raffinose and stachyose in daytime were higher than those at night. The content of raffinose in root and stem was not changed much, but the change of stachyose in root, stem and leaf was very obvious, especially in stem and leaf. In summary, the leaf is the main synthetic organ of raffinose, leaves, stems and roots are stachyose synthesis organ. Sucrose, raffinose and stachyose are the major transport forms of carbohydrates in R. glutinosa.

[Study on distribution and dynamic accumulation of catalpol and total iridoid in fresh Rehmannia glutinosa].

Iridoid glycosides were the main active ingredient of Rehmannia glutinosa, of which catalpol has the highest content. This work will provide theoretical basis for metabolic study and cultivation of iridoids on the basis of the dynamic accumulation of catalpol and total iridoids in the growth of R. glutinosa. The samples of rehmannia 85-5 were gathered in the same filed from July to October. The contents of catalpol and total iridoid glycosides were measured by HPLC and specteophotometric, respectively. The results showed that youngest leaves had the higher content of catalpol and total iridoid glyosides than that of the other two leaf ages in the same growth stage from July to September, while their content of catalpol and total iridoid glycosides were all decreased as the growth of leaves of R. glutinosa. The content of catalpol didn't differ significantly from July to September, whereas it has significantly increased in October in the three leaf stage. In the same stage, the wider the root diameter is, the higher content of the effective components are. In August and September, the total iridoid glycosides have the fastest accumulation. The content of catalpol was increased as the accumulation of total iridoid glycosides.