Analysis of ARID1B gene variants in two Chinese pedigrees with Coffin-Siris syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for two Chinese pedigrees affected with Coffin-Siris syndrome (CSS).@*METHODS@#Whole exome sequencing (WES) was carried out for the probands. Candidate variants were verified by Sanger sequencing of the probands and their family members.@*RESULTS@#The two probands were respectively found to harbor a heterozygous c.5467delG (p.Gly1823fs) variant and a heterozygous c.5584delA (p.Lys1862fs) variant of the ARID1B gene, which were both of de novo in origin and unreported previously. Based on the guidelines of American College of Medical Genetics and Genomics, both variants were predicted to be pathogenic (PVS1+PS2+PM2).@*CONCLUSION@#The c.5467delG (p.Gly1823fs) and c.5545delA (p.Lys1849fs) variants of the ARID1B genes probably underlay the CSS in the two probands. Above results have enabled genetic counselling and prenatal diagnosis for the pedigrees.

Analysis of genetic variation for a child affected with congenital insensitivity to pain with anhidrosis and albinism by whole genome sequencing / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic variation of a Chinese family affected with congenital insensitivity to pain with anhidrosis and albinism.@*METHODS@#Whole exome sequencing (WES) was carried out to screen potential variants within genomic DNA extracted from the proband and his parents. Whole genome sequencing (WGS) was applied when variants were not found completely. Suspected variants were validated by Sanger sequencing.@*RESULTS@#WES has identified a heterozygous c.1729G>C (p.G577R) variant of NTRK1 gene and two heterozygous variants of OCA2 gene, namely c.1363A>G (p.R455G) and c.1182+1G>A. WGS has identified two additional heterozygous variants c.(851-798C>T; 851-794C>G) in deep intronic regions of the NTRK1 gene.@*CONCLUSION@#The compound heterozygous variants of the NTRK1 gene probably underlay the congenital insensitivity to pain with anhidrosis. And the compound heterozygous variants of the OCA2 gene probably underlay the albinism in the proband. In the case where no variant is detected by WES in the coding region, WGS should be considered to screen potential variants in the whole genome.

Long period dynamics of viral load and antibodies for SARS-CoV-2 infection: an observational cohort study

OBJECTIVETo investigate the dynamics of viral RNA, IgM, and IgG and their relationships in patients with SARS-CoV-2 pneumonia over an 8-week period. DESIGNRetrospective, observational case series. SETTINGWenzhou Sixth Peoples Hospital PARTICIPANTSThirty-three patients with laboratory confirmed SARS-CoV-2 pneumonia admitted to hospital. Data were collected from January 27 to April 10, 2020. MAIN OUTCOME MEASURESThroat swabs, sputum, stool, and blood samples were collected, and viral load was measured by reverse transcription PCR (RT-PCR). Specific IgM and IgG against spike protein (S), spike protein receptor binding domain (RBD), and nucleocapsid (N) were analyzed. RESULTSAt the early stages of symptom onset, SARS-CoV-2 viral load is higher in throat swabs and sputum, but lower in stool. The median (IQR) time of undetectable viral RNA in throat swab, sputum, and stool was 18.5 (13.25-22) days, 22 (18.5-27.5) days, and 17 (11.5-32) days, respectively. In sputum, 17 patients (51.5%) had undetectable viral RNA within 22 days (short persistence), and 16 (48.5%) had persistent viral RNA more than 22 days (long persistence). Three patients (9.1%) had a detectable relapse of viral RNA in sputum within two weeks of their discharge from the hospital. One patient had persistent viral RNA for 59 days or longer. The median (IQR) seroconversion time of anti-S IgM, anti-RBD IgM, and anti-N IgM was 10.5 (7.75-15.5) days, 14 (9-24) days, and 10 (7-14) days, respectively. The median (IQR) seroconversion time of anti-S IgG, anti-RBD IgG, and anti-N IgG was 10 (7.25-16.5) days, 13 (9-17) days, and 10 (7-14) days, respectively. By week 8 after symptom onset, IgM were negative in many of the previously positive patients, and IgG levels remained less than 50% of the peak levels in more than 20% of the patients. In about 40% of the patients, anti-RBD IgG levels were 4-times higher in convalescence than in acute phase. SARS-CoV-2 RNA coexisted with antibodies for more than 50 days. Anti-RBD IgM and IgG levels, including anti-RBD IgM levels at presentation and peak time, were significantly higher in viral RNA short persistence patients than in long persistence patients. CONCLUSIONThis study adds important new information about the features of viral load and antibody dynamics of SARS-CoV-2. It is clear from these results that the viral RNA persists in sputum and stool specimens for a relatively long time in many patients. Anti-RBD may also serve as a potential protective antibody against SARS-CoV-2 infection, as viral persistence appears to be related to anti-RBD levels. Earlier treatment intervention also appears to be a factor in viral persistence. WHAT IS ALREADY KNOWN ON THIS TOPICThere are several reports about the serum antibodies against SARS-CoV-2. However, most of them evaluate diagnostic accuracy. Only two articles report dynamics of SARS-CoV-2 viral RNA and antibodies with serial samples, but the observation periods are within 30 days. None of the studies investigate the profiles of SARS-CoV-2 viral load and antibodies in a long period. Three reports investigate profiles in respiratory samples, but there are no reports on the dynamics of the viral load in stool samples. WHAT THIS STUDY ADDSIn both sputum and stool, SARS-CoV-2 RNA persists for a long time. The anti-RBD antibodies may involve in the clearance of SARS-CoV-2 infection. After eight weeks from symptom onset, IgM were negative in many of the previously positive patients, and IgG levels remained less than 50% of the peak levels in more than 20% of the patients. In about 40% of the patients, anti-RBD IgG levels increased 4-time higher in convalescence than in acute phase. Long persistence of SARS-CoV-2 viral RNA in sputum and stool presents challenges for management of the infection. The IgM/IgG comb test is better than single IgM test as a supplement diagnostic tool. Anti-RBD may be a protective antibody, and is valuable for development of vaccines.

Analysis of TWNK variant in a family affected with Perrault syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic etiology of two patients with Perrault syndrome (PRLTS) in a family.@*METHODS@#Whole exome sequencing (WES) was carried out to screen potential variants within genomic DNA extracted from the proband. Suspected variants were validated by clinical data and results of Sanger sequencing.@*RESULTS@#WES has identified two heterozygous variants of TWNK gene, namely c.1172G>A (p.Arg391His) and c.1844G>C (p.Gly615Ala). Sanger sequencing confirmed that the c.1172G>A (p.Arg391His), a known pathogenic variant, was derived from her father, while the c.1844G>C (p.Gly615Ala), a novel variant, was derived from her mother. Her brother, who was similarly affected, has carried the same compound heterozygous variants.@*CONCLUSION@#The compound heterozygous variants c.1172G>A (p.Arg391His) and c.1844G>C (p.Gly615Ala) of the TWNK gene probably underlie PRLTS in the sib pair. The above results have facilitated genetic counseling and prenatal diagnosis for the affected family.

Analysis of MYH3 gene variation and prenatal diagnosis for two pedigrees affected with congenital arthrogryposis / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic etiology of two pedigrees affected with congenital arthrogryposis.@*METHODS@#Whole exome sequencing (WES) was used to screen potential variations in the proband. Suspected variations were analyzed with bioinformatics software and validated by Sanger sequencing.@*RESULTS@#A heterozygous c.1123G>A (p.Glu375Lys) variation was detected in the proband and an affected fetus from pedigree 1, while a de novo heterozygous c.118 G>A (p.Val40Met) variation was detected in an affected fetus from pedigree 2.@*CONCLUSION@#The two heterozygous variations of the MYH3 gene probably underlie the disease in the pedigrees. Above results have facilitated genetic counseling and prenatal diagnosis.

Association of vitamin D level and vitamin D receptor gene FokI polymorphisms in pregnant women with fetal growth restriction / 中华全科医师杂志

Serum vitamin D level and vitamin D receptor (VDR) gene FokI polymorphisms were detected in 200 single full-term pregnant women who gave birth in our hospital during 2016 to 2018. The newborns with birth weight<2500 g were diagnosed as fetal growth restriction (FGR), there were 100 cases in FGR group and 100 cases in control group. The average level of vitamin D in pregnant women in FGR group was significantly lower than that of the control group [(30.1±10.9) vs. (36.1±15.8) nmol/L, P<0.05]. In the FGR group, the birth weight of infants in mother carrying ff genotype was significantly lower than that in mother carrying Ff and FF genotypes [(2073±90) g vs. (2242±122) g and (2349±96) g, P<0.05]. Pregnant women carrying Ff and FF genotypes had lower risk of FGR than those of carrying ff genotype (ORFf=0.31, 95％ CI: 0.17-0.76; ORFF=0.28, 95％CI: 0.11-0.46). The pregnant women with serum 25(OH)D level>30 nmol/L carrying F allele (FF+Ff) were set as reference, the risk of FGR in pregnant women with serum 25 (OH)D level ≤ 30 nmol/L carrying ff genotype was increased (OR=6.14, 95％CI: 2.13-13.23). The polymorphism of VDR gene FokI may be associated with the occurrence of FGR. In the case of vitamin D deficiency, the influence of ff genotype on FGR is more tangible.

Variant analysis for a pedigree affected with limb-girdle muscular dystrophy type 2D / 中华医学遗传学杂志

OBJECTIVE@#To analyze variant of SGCA gene in a Chinese pedigree affected with limb-girdle muscular dystrophy type 2D with whole exome sequencing (WGS).@*METHODS@#Multiplex ligation-dependent probe amplification (MLPA) was employed to detect large fragment deletion or duplication of the DMD gene. FastTarget next generation sequencing was used to detect variants of the DMD gene, and the result was verified by Sanger sequencing. After excluding the diagnosis of DMD for the proband, WGS was applied to test the proband and his parents. Suspected pathogenic variants were validated by Sanger sequencing.@*RESULTS@#No variant, deletion or duplication of the DMD gene was detected. Whole exome sequencing showed that the proband has carried compound heterozygous missense variants c.409G>A (p.Glu137Lys) and c.409G>C (p.Glu137Gln) in exon 5 of the SGCA gene, which were respectively inherited from his mother and father. Neither variant was found in DNA derived from the cord blood sample.@*CONCLUSION@#The c.409G>A (p.Glu137Lys) and c.409G>C (p.Glu137Gln) compound heterozygous missense variants probably underlie the disease in the proband. Above finding has facilitated genetic counseling and prenatal diagnosis for the family.

Analysis of SACS mutation in a family affected with autosomal recessive spastic ataxia of Charlevoix-Saguenay / 中华医学遗传学杂志

OBJECTIVE@#To carry out mutation analysis for a Chinese family affected with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS).@*METHODS@#Whole exome sequencing (WES) was used to screen potential mutations within genomic DNA extracted from the proband. Suspected mutation was validated by combining clinical data and results of Sanger sequencing.@*RESULTS@#A homozygous deletional mutation c.3665_3675delGTGCTGTCTTA (p.S1222fs) was found in the proband, for which her parents were both heterozygous carriers.@*CONCLUSION@#WES is capable of detecting mutation underlying this disorder and facilitating genetic counseling and prenatal diagnosis for the affected family. A novel pathogenic mutation of the SACS gene was discovered.

Whole exome sequencing analysis for a Chinese pedigree affected with X-Linked intellectual disability / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the clinical features and genetic mutation in a family affected with non-syndrome X-linked intellectual disability (NS-XLID) using whole exome sequencing (WES).</p><p><b>METHODS</b>Multiplex ligation-dependent probe amplification (MLPA) was applied to screen potential mutations of Fragile X syndrome (FXS). Whole exome sequencing (WES) and Sanger sequencing were screen for pathological mutations.</p><p><b>RESULTS</b>FXS was excluded by MLPA analysis. WES has discovered in the proband an ARX gene mutation c.88G>T, which was confirmed by Sanger sequencing. Combining his clinical phenotype with information from the OMIM database, it was inferred that the ARX mutation probably underlies the NS-XLID in the proband. The same mutation was found in his mother and two uncles but not in his father and sister.</p><p><b>CONCLUSION</b>WES is capable of revealing the mutation underlying NS-XLID and can facilitate genetic counseling for the affected families.</p>

Mutation analysis and prenatal diagnosis for 50 pedigrees affected with Duchenne/Becker muscular dystrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To establish individualized prenatal diagnosis program for families affected with Duchenne/Becker muscular dystrophy (DMD/BMD) and different clinical background using a variety of methods.</p><p><b>METHODS</b>Multiplex ligation-dependent probe amplification (MLPA) was performed on 50 patients suspected for DMD/BMD. For single exon deletions of the DMD gene, PCR was used for validating the results. For those without any deletion or duplication, Sanger sequencing was used to screen for DMD gene mutations in the children and their mothers. Prenatal genetic testing was provided to female carriers using chorionic villus, amniocentesis or cord blood samples. To ensure the accuracy of diagnosis, all prenatal specimens were also subjected to linkage analysis.</p><p><b>RESULTS</b>Among the 50 patients with DMD/BMD, 23 harbored large deletions, 11 only had single exon deletions, 10 harbored duplications, and 5 had small scare mutations. No mutation was detected in one family. For 37 women undergoing prenatal diagnosis, 10 fetuses were identified as affected males, 6 were female carriers, while 21 were not found to carry any mutation. Testing of creatine kinase was consistent with the results of prenatal diagnosis. For a patient harboring exon 51 deletion, the same mutation was found in a fetus but not in their mother. The proband and fetus had inherited the same haplotype, which suggested that the mother probably has germline mosaicism for the mutation.</p><p><b>CONCLUSION</b>Application of individualized methods for analyzing pregnant women with different clinical background can minimize the risk for giving birth to further children affected with DMD/BMD.</p>

Analysis of genome-wide copy number variations among fetuses with abnormalities detected by prenatal ultrasouography / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the genetic etiology of fetal abnormalities detected by prenatal ultrasound through single nucleotide polymorphism (SNP array) analysis.</p><p><b>METHODS</b>Two hundred and eight fetuses were tested with SNP array and conventional karyotyping. Complex copy number variations (CNVs) were verified with fluorescence in situ hybridization (FISH), multiplex ligation-dependent probe amplification (MLPA) and quantitative fluorescence polymerase chain reaction (QF-PCR).</p><p><b>RESULTS</b>For the 208 cases, the diagnostic yields of conventional karyotping and SNP assay were 8.2%(17/208) and 13.9%(29/208), respectively. For fetuses with malformations of the cardiovascular system, central nervous system or multiple systems, pathogenic CNVs was detected in 4.6% (8/174), 2.3%(4/174), and 1.1% (2/174) of all fetuses, respectively. No pathogenic CNVs was detected among those with abnormalities of the renal system, digestive system, skeletal system, facial dysmorphism or respiratory system.</p><p><b>CONCLUSION</b>CNVs are significantly related with birth defects. Compared with conventional karyotyping, SNP array is a better platform for CNVs detection and can provide more clues for genetic counseling, recurrence risk assessment and prenatal diagnosis.</p>

Mutation analysis for a Chinese family affected with Escobar syndrome by whole exome sequencing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To carry out mutation analysis for a Chinese family affected with Escobar syndrome.</p><p><b>METHODS</b>Whole exome sequencing (WES) was employed to detect potential mutation in the proband. Suspected mutations were validated by combining clinical data and result of Sanger sequencing.</p><p><b>RESULTS</b>A homozygous missense mutation c.715C>T (p.R239C) was detected in the proband and his brother who was also affected. The parents and the daughters of the proband carried the heterozygous mutation c.715C>T, while other family members did not carry the mutation.</p><p><b>CONCLUSION</b>Escobar syndrome is a rare genetic disorder. WES is able to discover genetic mutation underlying this disorder and facilitate genetic counseling and prenatal diagnosis for the affected family.</p>

Mutation analysis and prenatal diagnosis for 12 families affected with hereditary hearing loss and enlarged vestibular aqueduct / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To carry out mutation analysis and prenatal diagnosis for 12 families affected with hearing loss and enlarged vestibular aqueduct from southern Zhejiang province.</p><p><b>METHODS</b>Clinical data and peripheral venous blood samples of 38 members from the 12 families were obtained. Mutations of 4 genes, namely SLC26A4, GJB2, c.538C to T and c.547G to A of GJB3, m.1555A to G and m.1494C to T of 12S rRNA, were detected by PCR and Sanger sequencing. Maternal contamination was excluded by application of STR detection during prenatal diagnosis.</p><p><b>RESULTS</b>Among the probands from the 12 families, 11 were found to be compound heterozygotes or homozygotes and 25 were heterozygotes. All of the families were detected with IVS7-2A to G mutations, and 4 had a second heterozygous mutation (c.2168A to G of the SLC26A4 gene). Four rare pathogenic mutations, namely IVS5-1G to A, c.946G to T, c.1607A to G and c.2167C to G, were detected in another four families. In addition, the partner of proband from pedigree 3 was identified with compound heterozygous mutations of c.235delC and c.299-300delAT, and proband of pedigree 5 has carried a mutation of c.109G to A in GJB2. For SLC26A4 gene, prenatal diagnostic testing has revealed heterozygous mutations in 6 fetuses and compound heterozygous mutations in 2 fetuses.</p><p><b>CONCLUSION</b>IVS7-2A to G and c.2168A to G of the SLC26A4 gene were the most common mutations in southern Zhejiang. Such mutations can be found in most families affected with hearing loss and enlarged vestibular aqueduct, which may facilitate genetic counseling and prenatal diagnosis for such families.</p>

Analysis of clinical phenotypes and GJB2 gene mutations in families affected with hearing loss from southern Zhejiang / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the clinical features and pathological mutations in 44 families affected with hearing loss from southern Zhejiang, and to provide genetic counseling and prenatal diagnosis for 6 of the families.</p><p><b>METHODS</b>Microarray was employed to detect c.35delG, c.176del16, c.235delC and c.299-300delAT mutations of the GJB2 gene among 228 patients. For those carrying a single heterozygous mutation, the whole coding region of the GJB2 gene was analyzed by Sanger sequencing. For prenatal diagnosis, maternal DNA contamination was excluded by application of STR analysis.</p><p><b>RESULTS</b>The microarray assay has detected 49 patients with GJB2 mutations, which included 24 homozygous c.235delC mutations, 5 compound heterozygous c.235delC/c.176del16 mutations, 2 compound heterozygous c.235delC/c.299-300delAT mutations. Respectively, 16, 1 and 1 patients have carried single heterozygous c.235delC, c.176del16, and c.299-300delAT mutation. For the 16 patients, 7, 1, 1, 2, and 3 were detected by Sanger sequencing with a second heterozygous mutation of c.109G>A (2 of which were in conjunction with heterozygous c.176del16 and c.299-300delAT mutations), c.230G>A, c.427C>T, c.508-511 dupAACG, 79G>A+341A>G, respectively. Prenatal diagnosis revealed a compound heterozygous mutation in a fetus, heterozygous mutations in 4 fetuses, and no mutation of the GJB2 gene in 1 fetus.</p><p><b>CONCLUSION</b>The proportion of carriers for GJB2 gene mutations in patients with hearing loss from southern Zhejiang has reached 21.5%. The c.235delC, c.176del16, and compound c.299-300delAT and c.109G>A mutations can cause moderate to severe hearing loss. In most affected families, Heterozygous mutations may be identified by sequencing the whole coding region of the GJB2 gene. Genetic analysis and prenatal diagnosis can prevent birth of further affected children.</p>

Mutational analysis and prenatal diagnosis in a family affected with hypophosphatemic rickets / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the clinical characteristics and genetic mutation in a family affected with hypophosphatemic rickets.</p><p><b>METHODS</b>Whole exome sequencing (WES) was used to screen potential mutations in genomic DNA extracted from peripheral venous blood sample from the proband. Suspected mutation was confirmed with Sanger sequencing. Amniotic fluid was sampled from the proband for prenatal diagnosis. Potential maternal contamination was excluded by analysis of short tandem repeat (STR) markers.</p><p><b>RESULTS</b>WES has identified a heterozygous c.2058_2059insAGTT (p.L686fs) mutation of the PHEX gene in the proband, which was confirmed by Sanger sequencing in other affected individuals from the family. The mutation was detected in the amniotic fluid sample from the fetus but not among healthy members from the family.</p><p><b>CONCLUSION</b>Identification of the PHEX mutation by WES has facilitated genetic counseling and prenatal diagnosis for the family affected with hypophosphatemic rickets.</p>

Analysis of PKHD1 gene mutation in a family affected with infantile polycystic kidney disease / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze PKHD1 gene mutation in a family affected with autosomal recessive polycystic kidney disease (ARPKD).</p><p><b>METHODS</b>Genomic DNA was extracted from peripheral and cord blood samples obtained from the parents and the fetus. Potential mutations were identified using targeted exome sequencing and confirmed by Sanger sequencing. Pathogenicity of the mutation was analyzed using PolyPhen-2 and SIFT software.</p><p><b>RESULTS</b>Compound heterozygous mutations of c.11314C>T (p.Arg3772*) and a novel missense c.889T>A (p.Cys297Ser) of the PKHD1 gene were identified in the fetus. The mother was found to have carried the c.11314C>T mutation, while the father was found to have carried the c.889T>A mutation. PolyPhen-2 and SIFT predicted that the c.889T>A mutation is probably damaging.</p><p><b>CONCLUSION</b>A novel mutation in PKHD1 gene was detected in our ARPKD family. Compound heterozygous PKHD1 mutations were elucidated to be the molecular basis for the fetus affected with ARPKD, which has facilitated genetic counseling and implement of prenatal diagnosis for the family.</p>

Analysis and prenatal diagnosis of deafness-related gene mutations in patients with nonsyndromic hearing loss / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze deaf-related genes in patients with nonsyndromic hearing loss (NSHL) and set up a prenatal diagnosis system for such patients.</p><p><b>METHODS</b>Nine NSHL families were collected. Potential mutations of GJB2 (35delG, 176del16, 235delC, 299delAT), SLC26A4 (2168A> G, IVS7-2A> G), GJB3 (538C> T) and mtDNA (1494C> T, 12S rRNA 1555A> G) were detected by direct sequencing. Maternal blood contamination was excluded prior to the testing.</p><p><b>RESULTS</b>Sixteen patients from 4 families were detected with GJB2 mutations, 8 patients from 2 families were found with SLC26A4 mutations, and 4 patients from 2 families were found with mutations in mtDNA. For 2 patients from one remaining family, no mutations were found with above genes.</p><p><b>CONCLUSION</b>A diagnostic system for NSHL has been established, which may provide a basis for prenatal diagnosis and genetic counseling to NSHL families.</p>

Analysis of genomic copy number variation for a Chinese patient with split hand/split foot malformation / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To employ single nucleotide polymorphisms (SNP) microarray to detect copy number variations (CNVs) for the diagnosis of disease and molecular classification.</p><p><b>METHODS</b>For a patient with split-hand/split-foot malformation, genome-wide copy number variants SNP microarray was applied. Tiny copy number variations were verified by real-time fluorescent quantitative PCR.</p><p><b>RESULTS</b>The results of SNP microarray has revealed that the patient has carried a 0.39 Mb duplication in 10q24.31-24.32 (102 955 122-103 348 688), which has encompassed genes including LBX1, BTRC and POLL. By real-time fluorescent quantitative PCR, duplicate area encompassing the pathogenic genes have been verified. The results for LBX1, BTRC, POLL genes were all consistent with the SNP microarray test. Moreover, a duplication was detected in exon 9 of FBXW4 gene which is in nearby.</p><p><b>CONCLUSION</b>SNP chips can efficiently identify tiny CNVs (< 1.0 Mb). In combination with real-time fluorescence quantitative PCR, this may provide valuable information for prenatal diagnosis.</p>