A review of consensus statements, practice resources, standards and guidelines for clinical applications of next-generation sequencing technologies in the United States / 中华医学遗传学杂志

The use of whole exome sequencing (WES) for the detection of disease-causing variants of genetic diseases and for non-invasive prenatal screening (NIPS) of fetal aneuploidies are two major clinical applications of next generation sequencing (NGS). This article has summarized the official documents developed and updated by the American College of Medical Genetics and Genomics (ACMG) on governing WES and NIPS. These include the development of expert consensus policies and position statements on an ongoing basis to guide clinical application of NGS technology and variant analysis, establish evidence-based practical resources, as well as standards and guidelines to govern diagnosis and screening. These ACMG documents are valuable references to Chinese geneticists, but direct adoption of these standards and guidelines may not be practical due to the differences in disease-associated variant frequencies in Chinese population, socioeconomic status, and medical practice between the two countries. It is hoped that this review could facilitate the development of NGS and NIPS standards and guidelines that are consistent with international standards and concordant with medical genetics practice in China to provide high-quality, efficient and safe clinical services for patients and their families with genetic diseases.

Experience and lessons on guiding and governing clinical applications of chromosome microarray analysis in the United States / 中华医学遗传学杂志

Chromosome microarray analysis (CMA) has become the first-tier testing for chromosomal abnormalities and copy number variations (CNV). This review described the clinical validation of CMA, the development and updating of technical standards and guidelines and their diagnostic impacts. The main focuses were on the development and updating of expert consensus, practice resources, and a series of technical standards and guidelines through systematic review of case series with CMA application in the literature. Expert consensus and practice resource supported the use of CMA as the first-tier testing for detecting chromosomal abnormalities and CNV in developmental and intellectual disabilities, multiple congenital anomalies and autism. The standards and guidelines have been applied to pre- and postnatal testing for constitutional CNV and tumor testing for acquired CNV. CMA has significantly improved the diagnostic yields but still needs to overcome its technical limitations and face challenges of new technologies. Guiding and governing CMA through expert consensus, practice resource, standards and guidelines in the United States has provided effective and safe diagnostic services to patients and their families, reliable diagnosis on related genetic diseases for clinical database and basic research, and references for clinical translation of new technologies.

Correlation between fetal cranial nervous system malformation and chromosome abnormality / 中华实用儿科临床杂志

Objective@#To investigate the correlation between fetal cranial nervous system malformation and chromosome abnormality.@*Methods@#The pregnant women with fetal cerebral nervous system dysplasia were collected from January 2013 to August 2018 at the Prenatal Diagnostic Center of the Sixth Affiliated Hospital of Guangzhou Medical University.The fetus was diagnosed by ultrasonography and karyotype analysis.@*Results@#A total of 18 cases of abnormal karyotypes were detected from 85 patient samples, and the abnormal rates were 21.18%.Single cranial nervous system malformation was found in 47 cases, abnormal karyotypes in 4 cases, multiple system malformation in 38 cases, and abnormal karyotypes in 14 cases, and the abnormal karyotype rate of multiple system malformation was higher than that of single cranial nervous malformation (36.84% vs.8.51%, χ2=10.101, P=0.001 5). And the 88.89%(16/18 cases)of abnormal karyotypes were founded in the early and middle pregnancy (≤28 weeks). The abnormal karyotype detection rates of cranial nervous system malformation associated with cardiovascular, skeletal and limb, facial neck abnormalities were 58.82% (10/17 cases), 50.00% (6/12 cases) and 50.00% (9/18 cases), respectively.In the fetal phenotypes, the abnormal karyotype detection rates of choroid plexus cysts were up to 64.29%, followed by arachnoid cysts (50.00%), craniocerebral abnormalities (45.45%) and holoprosencephaly (36.36%).@*Conclusions@#Chromosomal aneuploidy or structural abnormalities can lead to abnormal development of the fetal cranial nervous system, in which the rates of abnormal karyotypes on fetal cranial nervous with cardiovascular malformation and choroid plexus cysts are the highest.

Correlation between fetal cranial nervous system malformation and chromosome abnormality / 中华实用儿科临床杂志

Objective To investigate the correlation between fetal cranial nervous system malformation and chromosome abnormality.Methods The pregnant women with fetal cerebral nervous system dysplasia were collected from January 2013 to August 2018 at the Prenatal Diagnostic Center of the Sixth Affiliated Hospital of Guangzhou Medical University.The fetus was diagnosed by ultrasonography and karyotype analysis.Results A total of 18 cases of abnormal karyotypes were detected from 85 patient samples,and the abnormal rates were 21.18％.Single cranial nervous system malformation was found in 47 cases,abnormal karyotypes in 4 cases,multiple system malformation in 38 cases,and abnormal karyotypes in 14 cases,and the abnormal karyotype rate of multiple system malformation was higher than that of single cranial nervous malformation (36.84％ vs.8.51％,x2 =10.101,P =0.001 5).And the 88.89％ (16/18 cases) of abnormal karyotypes were founded in the early and middle pregnancy (≤ 28 weeks).The abnormal karyotype detection rates of cranial nervous system malformation associated with cardiovascular,skeletal and limb,facial neck abnormalities were 58.82％ (10/17 cases),50.00％ (6/12 cases) and 50.00％ (9/18 cases),respectively.In the fetal phenotypes,the abnormal karyotype detection rates of choroid plexus cysts were up to 64.29％,followed by arachnoid cysts (50.00％),craniocerebral abnormalities (45.45％) and holoprosencephaly (36.36％).Conclusions Chromosomal aneuploidy or structural abnormalities can lead to abnormal development of the fetal cranial nervous system,in which the rates of abnormal karyotypes on fetal cranial nervous with cardiovascular malformation and choroid plexus cysts are the highest.

Deficiency of rpoS is the major factor leading to attenuation of Salmonella enterica serovar Choleraesuis vaccine strain C500 / 中国人兽共患病学报

Salmonella enterica serovar Choleraesuis strain C500 is a live attenuated vaccine that has been widely used in Chi‐na for over 50 years to prevent piglet paratyphoid .However ,as C500 is obtained by chemical methods ,the genetic background of this strain remained unclear .In this study ,we compared the genomic differences between the virulent reference strain C 78‐2 and C500 by suppression subtractive hybridization combined with the mirror orientation selection method (MOS‐SSH ) .Six genes (asr ,ydgF ,ydgD ,ydgE ,rpoS ,and ptsG) were lost in C500 strain .Using real‐time PCR analysis ,we demonstrated that the genes regulated by rpoS ,a vital transcriptional regulator playing an important role in Salmonella infection ,were downregulated in C500 .Additionally ,the virulence of the rpoS mutant strain C78‐2ΔrpoS was 100 000 times lower than the parental strain in BALB/c mice .So loss of rpoS gene is the major factor leading to the attenuation of C500 strain .