A prospective study of genetic screening of 2 060 neonates by high-throughput sequencing / 中华医学遗传学杂志

OBJECTIVE@#To assess the value of genetic screening by high-throughput sequencing (HTS) for the early diagnosis of neonatal diseases.@*METHODS@#A total of 2 060 neonates born at Ningbo Women and Children's Hospital from March to September 2021 were selected as the study subjects. All neonates had undergone conventional tandem mass spectrometry metabolite analysis and fluorescent immunoassay analysis. HTS was carried out to detect the definite pathogenic variant sites with high-frequency of 135 disease-related genes. Candidate variants were verified by Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA).@*RESULTS@#Among the 2 060 newborns, 31 were diagnosed with genetic diseases, 557 were found to be carriers, and 1 472 were negative. Among the 31 neonates, 5 had G6PD, 19 had hereditary non-syndromic deafness due to variants of GJB2, GJB3 and MT-RNR1 genes, 2 had PAH gene variants, 1 had GAA gene variants, 1 had SMN1 gene variants, 2 had MTTL1 gene variants, and 1 had GH1 gene variants. Clinically, 1 child had Spinal muscular atrophy (SMA), 1 had Glycogen storage disease II, 2 had congenital deafness, and 5 had G6PD deficiency. One mother was diagnosed with SMA. No patient was detected by conventional tandem mass spectrometry. Conventional fluorescence immunoassay had revealed 5 cases of G6PD deficiency (all positive by genetic screening) and 2 cases of hypothyroidism (identified as carriers). The most common variants identified in this region have involved DUOX2 (3.93%), ATP7B (2.48%), SLC26A4 (2.38%), GJB2 (2.33%), PAH (2.09%) and SLC22A5 genes (2.09%).@*CONCLUSION@#Neonatal genetic screening has a wide range of detection and high detection rate, which can significantly improve the efficacy of newborn screening when combined with conventional screening and facilitate secondary prevention for the affected children, diagnosis of family members and genetic counseling for the carriers.

Enlarged multicystic dysplastic kidneys with oligohydramnios during infancy caused by NPHP3 gene mutation / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical features and genomic abnorm ality of a fetus enlarged multicystic dysplastic kidneys with oligohydramnios caused by NPHP3 gene mutation.@*METHODS@#The fetuse was found to have multicystic dysplastic kidneys with oligohydramnios upon ultrasonography during the second trimester. Following induced abortion, fetal tissue was collected for the extraction of DNA, chromosomal microarray analysis (CMA) and whole exome sequencing (WES). Sanger sequencing was used to verify the suspected variants in the family.@*RESULTS@#Antenatal ultrasound examination at 19 weeks showed "polycystic" kidneys with Oligohydramnios. Delivery was by induced labour because of the critically low amniotic fluid volume. Testing of CMA was normal. WES showed a compound heterozygous mutation of c.1817G>A, p.W606X; c.432dupA, p.E145Rfs*18 mutations are novel mutations in this study.@*CONCLUSION@#The research may further expand the NPHP3 gene mutation spectrum. Enlarged multicystic dysplastic kidneys with oligohydramnios caused by NPHP3 gene mutation at least include one or two splice site mutation, frameshift mutation or nonsense mutation foetal poor prognosis.

Study on newborn screening for Duchenne muscular dystrophy and diagnostic strategy / 中华医学遗传学杂志

OBJECTIVE@#To establish a newborn screening system for Duchenne muscular dystrophy (DMD) through assessment of MM isoenzyme of creatine kinase (CK-MM) activity.@*METHODS@#The CK-MM level was detected using dry blood spot filter paper from 10 252 male newborns. The results were grouped based on their gestational age, sampling time and intervals between the experiments. The threshold value for CK-MM necessitating genetic testing was determined. Next-generation sequencing (NGS) was carried out for those with a CK-MM value over the threshold, and the result was verified by multiplex ligation-dependent probe amplification (MLPA).@*RESULTS@#Based on the result of non-parametric rank sum test, the median CK-MM concentration has increased with the gestational age, and was inversely correlated with the age of the newborns among unaffected specimens. CK-MM on dry blood spot filter paper can be stable for 14 days at 2-8℃. Statistical analysis of CK-MM value of the 10 252 neonates suggested that the threshold may be set as 700 ng/mL. Exonic deletions were found in 2 confirmed cases, whose CK-MM level was greater than 2000 ng/mL.@*CONCLUSION@#Detection of CK-MM in dry blood spot filter paper has provided an effective method for newborn screening of DMD. This simple and inexpensive method can be used for large-scale screening, which is of great value to the early intervention and treatment of the disease.

Prenatal diagnosis and genetic analysis of two fetuses with paternally derived 17q12 microdeletions / 中华医学遗传学杂志

OBJECTIVE@#To reported on two fetuses diagnosed with 17q12 microdeletion syndrome.@*METHODS@#The two fetuses were respectively found to have renal abnormalities and polyhydramnios upon second and third trimester ultrasonography. Umbilical cord blood of the first fetus and amniotic fluid of the second fetus were subjected to single nucleotide polymorphism array (SNP-array) analysis. After 17q12 microdeletion was found in the first fetus, SNP-array was carried out on peripheral blood samples of the parents to determine its origin. With the medical history of the parents taken into consideration, the father underwent high-throughput sequencing for 565 urinary system-related genes to exclude pathogenic or likely pathogenic variants associated with congenital malformations of the urinary and reproductive systems.@*RESULTS@#In both fetuses, SNP-array has revealed a 1.42 Mb deletion at 17q12, or arr[hg19]17q12 (34 822 465-36 243 365) × 1. In both cases the microdeletion was inherited from the father, in whom no urinary disease-related pathogenic or likely pathogenic variants was identified.@*CONCLUSION@#Paternally derived 17q12 microdeletions probably underlay the genetic etiology of the two fetuses with renal ultrasound abnormalities and polyhydramnios. SNP-array can enable the diagnosis and facilitate genetic counseling and prenatal diagnosis for the families.

Effects of growth-discordant twin pregnancies on thyroid function of neonates / 中华围产医学杂志

Objective To investigate the effects of growth-discordant twin pregnancies on neonatal thyroid stimulating hormone (TSH) level and congenital hypothyroidism (CH).Methods A total of 3 444 live-birth twin neonates born between January 1,2012 and December 30,2014 in Ningbo City were enrolled.Blood samples via heel puncture were collected and tested.Incidence of CH in singleton and twin neonates was compared.Deviation of birth weight larger than 25％ in twin neonates was set as the criteria for discordant growth.TSH and 17 α-hydroxylase levels in CH twins and normal twins,with or without discordant growth,were compared.Chi-square and non-parametric statistics were performed for data analysis.Results The incidence of CH in twin neonates was 0.56％ (19/3 444),higher than that in singleton neonates [0.09％ (203/225 712),x2=76.225,P＜0.01].Among nineteen CH twins,CH occurred in both twins in eight cases (four twins) and in one of the twins in eleven cases.The gestational age at birth in the eight CH twins were less than 37 weeks,with four males and four females;five were low birth weight infants;one twin were dichorionic,and three twins were monochorionic.In the eleven cases of CH occurring in one of the twins,the gestational age was less than 37 weeks in nine cases,eight were low birth weight infants,six were male and five female;seven were monochorionic and four were dichoronic twins.Five cases of temporary hypothyroidism were all low birth weight infants among the growth-discordant twins.CH cases in growth-discordant group had lower birth weight than their normal twins [M(P25-P75),2 100 (1 800-2 600) vs 2 770 (2 530-2 960) g,Z=4.369],and a higher TSH level [15.4 (11.8-18.5) vs 6.4 (4.8-7.9) mU/L,Z=6.339] (both P＜0.05).In normal twins with or without discordant growth,the neonates with a lower birth weight had a higher TSH level [3.6(2.5-4.7) vs 2.4(1.8-2.9) mU/L,Z=0.962] in weight consistent group,compared with 6.0(4.4-7.8) vs 3.4(1.9-4.1) mU/L in weight inconsistent group (Z=4.369),both P＜0.05.Conclusions In the growth-discordant twins,neonates with a lower birth weight have a higher TSH level and a higher risk of temporary hypothyroidism.

Serological prenatal screening results of sIUFD when twin pregnancy / 中华检验医学杂志

Objective To study whether there was significant difference between pregnant women , data and the results of prenatal screening of single intrauterine fetal death ( sIUFD) when twin pregnancy and singleton pregnancy for guiding the clinical prenatal screening and risk consulting .Methods By comparative study, 56 cases of sIUFD when twin pregnancy were recorded from 2011 to 2014 in Ningbo Prenatal Diagnosis Center , all were natural pregnancy , the sistens gestational weeks were less than 14 weeks , and 4 993 natural singleton pregnancy .The pregnant women , data and the results of serological prenatal screening between sIUFD and singleton pregnancy were analyzed by t-test and rank sum test .Separately , the 56 cases of prenatal screening , risk value was calculated according to the twins and singleton , then the difference were analyzed combined with the results of follow-up.Results Pregnant women , data of two groups were analyzed, there were no statistically significant difference between sIUFD and singleton pregnancy .The age of sIUFD and singleton was (27 ±3)year-old and (27 ±3)year-old respectively, t=2.56, P>0.05; the weight of sIUFD and singleton was (55.2 ±10.23 ) kg and (56 ±10.34) kg, t=4.268, P>0.05.The gestational weeks of sIUFD and singleton were (39.21 ±0.78)weeks and (39.1 ±0.91) weeks, t=1.3, P>0.05;the weight of newborn was (3.38 ±0.41) kg and (3.31 ±0.43) kg, t=1.9, P>0.05.The AFP multiple of median (AFPMOM) of sIUFD and singleton was 1.41(0.99,1.83) and 1.02(0.84,1.24), Z=5.337, P0.05;unconjugated estriol multiple of median of sIUFD and singleton was 1(0.79,1.16) and 1.01(0.85,1.21), Z=1.334, P>0.05.Trisomy 21 risk of sIUFD and singleton was 7 750(2 200,28 000) and 5 300(2 000,12 000), Z=2.093, P<0.05, that had significant difference.The 56 cases of prenatal screening risk value was calculated according to the twins and singleton , among whom 42 cases had the same conclusion , 14 cases had the different conclusion .Among them, according to singleton calculation , 3 cases for high risk, according to the twin calculation of high risk for 17 cases,χ2 =12.1, P <0.05.According to follow-up, all newborns were normal.Conclusions For the natural pregnancy , sIUFD when twin pregnancy , if the sistens gestational weeks less than 14 weeks, the risk of prenatal screening results calculated according to singleton will be more reasonable , as for the prenatal screening for twin pregnancy , the method needs further exploration .

Analysis of fetal chromosomal karyotypes in 4539 elderty gravida in Ningbo, China / 中华检验医学杂志

Objective To analysis and summary the chromosome abnormal existing in old pregnant women from 2002 to 2013,and to provide basis for clinicians intervene the fetus with chromosome disorders.Methods The 4 539 pregnant women in Ningbo city from 2002 August to 2013 October accepted the fetal karyo type detection,were retrospective analyzed,the frequency of abnormal chromosomal karyotypes was calculated according to different age groups,and the pregnancy outcomes of the old pregnant women were followed up.Thechi-square testswere performed on the frequency dateof the abnormal chromosome karyotype,polymorphism,and serum screening of high risk for fetal chromosome detection of less than 35-years-old pregnant women.Results The total of advanced maternal age pregnancyduring the past 11 years in Ningbo City is 32 080,and the follow-up rate was 99.90％,there are 10 infants borned with chromosomal abnormalities,the 1 290 caseswere detected withadverse pregnancy.A total of 4 539 advanced maternal age pregnancyaccepted amniocentesis,in those we found 107 cases of chromosome abnormality fetus,116 cases of polymorphism.A total of 5 232 high-risk pregnant women accepted the serum screening in the same period (less than 35 years old),finding 135 cases of fetal chromosome abnormal and 69 cases of polymorphism.Conclusion To strengthen the prenatal diagnosis,especially for puerperae above the age of 39,will lower the birth rate of infants with chromosome disease and will be conducive to the high quality of population in Ningbo.

A retrospective analysis about second trimester screening for Down syndrome in intermediate risk population / 中华围产医学杂志

Objective To investigate rational management for pregnant women with intermediate risk of Down syndrome (DS) through a retrospective analysis of second trimester maternal screening results for DS.Methods Second-trimester triple maternal serum screening for DS was performed.High risk ( ≥ 1/270) pregnant women received prenatal diagnosis.Intermediate (1/1000 to 1/270) and low (＜1/1000) risk pregnant women received routine obstetric examination.Data of ultrasound diagnosis,karyotype analysis of amniotic fluid and postpartum follow-up were collected.Outcomes of pregnant women were retrospectively analyzed.The incidences of DS among three groups were compared.Data of different groups were compared with Fisher exact or Chi-square test.Results Eighty-six thousand eight hundred and seventy-four pregnant women accepted maternal serum screening and outcomes of 86 126 cases were followed up,among which 4342 cases were DS high risk,8196 intermediate and 73 588 low risk.The incidence of DS was 6.22‰(27/4342) for high risk,0.73 ‰ (6/8196) for intermediate risk and 0.04 ‰ (3/73 588) for low risk group.The incidence of DS was higher in high risk group than in intermediate risk group (Fisher exact probability,P=0.000),and was higher in intermediate risk group than in low risk group (Fisher exact probability,P=0.000).Comparison among the three subgroups within intermediate risk group showed no significant differences (x2 =0.047,P =0.977).Conclusions Pregnant women with intermediate risk of DS should be paid more attention.Reasonable management such as ultrasound diagnosis and prenatal consultation should be provided.