To explore the genetic basis for a case of recurrent fetal congenital hydrocephalus. Next-generation sequencing was carried out for the fetus, the gravida and two of her sisters. The fetus was found to harbor a c.1765T>C (p.Tyr589His) mutation in exon 14 of the L1CAM gene, which was derived from the gravida. Male fetuses with recurrent hydrocephalus should be subjected to testing of the L1CAM gene to facilitate genetic counseling and prenatal diagnosis.
To analyze genetic variant in a pedigree affected with congenital high myopia. Whole exome sequencing (WES) was carried out for the proband. Suspected variation was verified with Sanger sequencing. The pedigree was also subjected to co-segregation analysis. WES has identified a novel splice site heterozygous variant (c.2556+1G>A) in the COL11A1 gene in the proband. Co-segregation analysis of the pedigree showed that the affected mother and two daughters of the proband have carried the same variant(c.2556+1G>A), while his unaffected father and sister did not. Based on the ACMG Standards and Guidelines for the Interpretation of Sequence Variants, the variant was classified as "likely pathogenic" (PVS1+PM2). A novel splice variant (c.2556+1G>A) of the COL11A1 gene has been identified in a pedigree affected with congenital high myopia, which probably underlies the disease.
To screen for potential variants of GCDH gene in 3 patients clinically diagnosed as glutaric aciduria type Ⅰ. GCDH gene variants was detected by Sanger sequencing among the three children and their family members. Sanger sequencing showed that patient 1 carried compound heterozygosity variants of c.532G>A (p.Gly178Arg) and c.655G>A (p.Ala219Thr) of the GCDH gene, while his father and mother respectively carried heterozygous c.532G>A(p.Gly178Arg) and c.655G>A (p.Ala219Thr) variants. Patient 2 carried c.532G>A (p.Gly178Arg) and a novel c.1060G>T (p.Gly354Cys) compound heterozygous variant, while his father and mother respectively carried heterozygous c.532G>A (p.Gly178Arg) and c.1060G>T (p.Gly354Cys) variant. Patient 3 carried homozygous c.532G>A (p.Gly178Arg) variant of the GCDH gene, for which both of his parents were heterozygous carriers. The GCDH gene variant probably underlie the glutaric aciduria type Ⅰ among the 3 patients. Identifcation of the novel variant has enriched the spectrum of GCDH gene varian
To explore the genetic basis for an infant featuring developmental delay, hand deformity and hypertonia of extremities. Clinical data and peripheral blood samples of the proband and her parents were collected. Following DNA extraction, potential mutations were screened on an Ion PGM platform using a gene panel. Suspected mutation was verified by PCR and Sanger sequencing. A novel heterozygous nonsense mutation, c.2521C>T(p.R841X), was identified in the NIPBL gene. The mutation may cause premature termination of translation of the adhesion protein loading factor at 841st amino acids. The same mutation was not found in her parents and 931 healthy controls, and was absent from public databases including ExAC and 1000G. Bioinformatic analysis suggested the mutation to be disease causing. The c.2521C>T (p.R841X) mutation of the NIPBL gene probably underlies the Cornelia De Lange syndrome in the infant. Prenatal diagnosis may be provided to this family upon their subsequent pregnancy.
To carry out mutation analysis for patients with myelodysplastic syndromes (MDS) and a normal karyotype. Targeted capture and next-generation sequencing (NGS) was carried out using a customized 49-gene panel. FLT3 internal tandem duplication (FLT3-ITD), CALR, NPM1 and CEBPA mutations were detected by PCR and Sanger sequencing. Sixty-two patients (80.5%) were found to harbor at least one mutation. Each patient has carried 2.21 mutations in average. Coexistence of ≥ 3 mutations was common (43.7%). The most commonly mutated genes were RUNX1 (23.4%, 18/77), ASXL1 (18.2%, 14/77), NPM1 (15.6%, 12/77), U2AF1 (15.6%, 12/77), DNMT3A (11.7%, 9/77). Patients with SF3B1 mutations were significantly older than those with ASXL1 mutations (P=0.023). Mutations of the DNMT3A gene were significantly associated with the blood platelet level compared with BCOR mutations (P=0.02). No significant difference was found in the number and rate of mutations between those under or above 60-year-old. Among 67 patients with clinical follo
To detect potential mutation in a Chinese pedigree affected with congenital limb malformations. Clinical data was collected. Genomic DNA was extracted from peripheral blood samples of family members. The zone of polarizing activity regulatory sequence (ZRS) were amplified by PCR and subjected to direct sequencing. Among the 13 individuals in this pedigree, there were 4 PPD patients, who were characterized by varying degrees of deformity. The female patients suffered triphalangeal thumb and preaxial polydactyly, while the male patients only had preaxial polydactyly. Only one patient had foot involvement. TA heterogeneous mutations was discovered in the ZRS (105C>G) in all patients, the same mutation was not detected in 2 healthy family members. The inheritance pattern of PPD was autosomal dominant inheritance. There was a significant variability of symptoms among family patients. The heterozygous mutation of the ZRS (105C>G) probably underlie the disease.
To explore the correlation between fetal nuchal fold (NF) thickening and fetal chromosomal abnormality. In total 919 pregnant women undergoing ultrasound examination were selected for interventional prenatal diagnosis in order to detect fetal chromosomal abnormality. The detection rate of chromosomal abnormality has significantly increased with NF thickness, advanced maternal age, presence of other ultrasound abnormalities (P<0.05). Trisomy 21 was the most common abnormality, and there was a prepondance for male fetuses. Increased NF thickness is strongly associated with the risk of fetal chromosomal abnormalities, advanced maternal age and presence of additional ultrasound abnormalities.
To explore the genetic basis of a child with chronic kidney disease featuring renal shrinkage and creatinine increase. Peripheral venous blood samples were taken from the child, his brother and two parents and subjected to whole exome sequencing. Suspected mutations were verified by Sanger sequencing. Bioinformatic analysis was carried out to predict the influence of mutations on the structure and function of the protein product. High-throughput and Sanger sequencing revealed that the child has carried compound heterozygous mutations of the COL4A4 gene, namely c.4550T>G in exon 47 (inherited from his mother) and c.199C>T in exon 5 (inherited from his father). Neither mutation was reported previously. Bioinformatic analysis showed that both mutations have located in highly conserved regions. The same mutations were not found in his brother. The compound heterozygous c.4550T>G and c.199C>T mutations probably underlie the disease in this child. The findings have enriched the mutation spectrum of the COL4A4 gene.
To report a patient with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) manifesting as lumbago, hunchback and Parkinson's syndrome. A 49-years-old male CADASIL patient was reported. Results of clinical examination, neuroimaging and genetic testing were analyzed. His family members were also subjected to genetic testing. Related literature was reviewed. The patient had no typical symptoms of CADASIL such as headache, repeated stroke, dementia and emotional disorders, but progressive Parkinson's syndrome, late onset lumbago, hunchback, dysphagia, and diplopia. Brain MRI showed left basal ganglia and external capsule lacunar infarction. Genetic testing revealed a point mutation c.1630C>T (p.R544C) in exon 11 of the NOTCH3 gene. A heterozygous mutation was detected in the same gene in his mother, elder sister and younger brother, all of whom showed different clinical phenotypes. The clinical features of CADASIL are heterogeneous. Lumbago, humpback, and Parkins
To analyze the phenotype and genotype of a pedigree affected with congenital dysfibrinogenemia. Liver and kidney functions of the proband and her relatives were determined. Coagulation tests including prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time(TT), fibrin(ogen) degradation products (FDPs), D-dimer(D-D) and the calibration experiment of protamine sulfate of against plasma TT were detected in the proband and her predigree members. The activity and antigen of fibrinogen (Fg) in plasma were measured by Clauss method and immunonephelometry method, respectively. All of the exons and exons-intron boundaries of the three fibrinogen genes (FGA, FGB and FGG) were subjected to PCR amplification and Sanger sequencing. Potential influence of the suspected mutations were analyzed with bioinformatics software including PolyPhen-2, SIFT and Mutation Taster. The proband had normal PT, APTT, FDPs, D-D and prolonged TT (31.8 s). The activity of fibrinogen (Fg) in plasma was significant
To summarize the clinical characteristics and identify gene mutations of 2 probands with Rubinstein-Taybi syndrome (RSTS). Clinical characteristics of 2 probands with Rubinstein-Taybi syndrome were summarized. Genomic DNA was extracted from peripheral blood samples from the patients and their parents. Genomic DNA was subjected to whole exome next generation sequencing. Suspected variants were confirmed by Sanger sequencing. The two patients were characterized by typical facial features, broad thumbs and big toes, intellectual disability, and postnatal growth retardation. Two variants of the CREBBP gene, namely c.3779+1G>A and c.5052_c.5053insT, were respectively identified in the 2 patients. Among these, c.3779+1G>A was a previously known pathological mutation, while c.5052_c.5053insT was unreported previously. Both variants were predicted to be pathological. Two cases of Rubinstein-Taybi syndrome were diagnosed, which facilitated the diagnosis and genetic counselling.
To explore the influence of uniparental disomy (UPD) on bipartite and tripartite paternity testing. Two cases of paternity testing were analyzed by multiplex amplification and capillary electrophoresis typing. Suspected UPD was verified by using single nucleotide polymorphism array (SNP array). Parental power index was calculated by using a bipartite or tripartite model. The two cases were found to harbor respectively three short tandem repeats on chromosome 2 and two short tandem repeats on chromosome 15. SNP array verified that both cases were of UPD. Case 1 had a parental power index of 122274987565.23 by a tripartite model, while case 2 had a parental power index of 13500.8463 by a bipartite model. Based on the technical specification, the conclusions supported a biological parent-child relationship in both cases. UPD may lead to misjudgment of paternity testing. The possibility of UPD should be considered when certain loci which do not conform to Mendelian inheritance have aggregated to one chromosome.
To assess the value of dry blood spot tandem mass spectrometry for the diagnosis of autism spectrum disorder (ASD). Peripheral blood samples of 277 autistic children were collected. Their amino acid and carnitine profiles were detected by liquid chromatography tandem mass spectrometry. Urine samples of suspected patients were collected for verification by gas chromatography mass spectrometry. Blood samples were also taken for genetic testing. Of the 277 children with ASD, 19 (6.9%) were suspected to be with inborn error of metabolism (IEM), which included 6 cases with amino acidemia, 9 with organic acidemia and 4 with fatty acidemia. Three cases of phenylketonuria, one case of homocysteinemia, one case of propionemia, one case of methylmalonic acidemia, one case of glutaric acidemia, one case of isovaleric acidemia, one case of argininemia, one case of citrullinemia I and four cases of primary carnitine deficiency were confirmed by genetic testing, which yielded an overall diagnostic rate of 5.1% (14/277). Ou
To identify pathogenic variants in 5 sporadic patients and two Chinese pedigrees affected with 17-hydroxylase deficiency (17-OHD). Peripheral blood samples were collected with informed consent. Variants of CYP17A1 gene were screened by PCR and Sanger sequencing. Suspected mutations were validated in other members of the pedigrees. Gene sequencing has identified a homozygous c.985_987delTACinsAA (Y329Kfs) mutation in exon 6 of the CYP17A1 gene in 4 patients and the sister of case 3. Case 1 was found to harbor compound heterozygous mutations c.1459_1467del9 (p.D487_F489del) and c.1244-3C>A. The parents and brother of cases 2 and 5 were heterozygous carriers of a c.985_987delTACinsAA(Y329Kfs) mutation. Mutations of the CYP17A1 gene probably underlie the pathogenesis of 17-OHD, for which c.985_987delTACinsAA(Y329Kfs) is the most common. The c.1244-3C>A is a novel mutation. Above results have facilitated genetic counseling for the affected families.
To screen for pathogenic variants in the coding regions of STK11 gene among Chinese patients with Peutz-Jeghers syndrome (PJS). Peripheral blood samples were collected from 64 patients. The coding regions of the STK11 gene were detected by PCR and Sanger sequencing. Fourty-eight patients were found to harbor STK11 gene variants, which included 39 types of variants consisting of missense, nonsense, insertional, deletional and splice site variants. Among 64 PJS patients, the detection rate of point variants was 75.00% (48/64), of which missense variants accounted for 29.17% (14/48), nonsense variants accounted for 29.17%(14/48), insertion variants accounted for 2.08% (1/48), deletional variants accounted for 10.42% (5/48), and splice site variants accounted for 29.17% (14/48). The detection rates of sporadic cases and those with a family history were 71.8% (28/39) and 80.0% (20/25), respectively. Two variants (c.250A>T, c.580G>A) occurred in 3 PJS probands. Thirteen variants were unreported previously and were
To explore the genetic basis of a neonate with argininosuccinic aciduria (ASA). A neonate with lethargy and food refusal was admitted. The patient had myoclonus, myasthenia, uroschesis, irregular breathing and paroxysmal ventricular tachycardia, and died at 75 hours after birth. Laboratory test showed marked increase in blood ammonia (1249.8 μmol/L). Peripheral blood samples of the patient, her parents and sister were collected and subjected to trio whole-exome sequencing. Whole-exome sequencing revealed that the patient has carried compound heterozygous mutations of the argininosuccinate lyase (ASL) gene, namely c.425(exon5)_c.426(exon5) insAGCTCCCAGCT (p.Thr142Thrfs*37) and c.626(exon8)delT (p.Leu209Argfs*42). The patient was diagnosed as ASA caused by ASL gene mutations. Her parents and her elder sister were heterozygous carriers of the above mutations and had a normal phenotype. ASA is a severe congenital genetic metabolic disease and can manifest as onset of hyperammonemia in neonates. The clinical diagn
To explore phenotypic and mutational characteristics of a pedigree affected with autosomal dominant Charcot-Marie-Tooth disease (CMT) and nephropathy. Clinical data of the proband and his family members was collected. Electrophysiology, renal biopsy and next-generation sequencing were carried out for the proband. The proband presented with distal lower limb weakness and proteinuria in childhood. His mother and brother had similar symptoms. Electrophysiological test of the proband revealed demyelination and axonal changes in both motor and sensory nerves. Renal biopsy suggested focal segmental glomerulosclerosis. Genetic testing revealed a heterozygous c.341G>A (p.G114D) mutation in exon 2 of the INF2 gene. The phenotypic feature of the pedigree is autosomal dominant intermediate CMT and focal segmental glomerulosclerosis, which may be attributed to the c.341G>A mutation of the INF2 gene.
To explore the genetic basis for a patient with autism. High-throughput sequencing was carried out to detect copy number variations in the patient. DNA sequencing found that the patient has carried a 0.11 Mb deletion in distal 2p16.3 spanning from genomic position 50 820 001 to 50 922 000, which resulted removal of exon 6 and part of intron 7 of the NRXN1 gene. The same deletion was not found his parents and brother. Partial deletion of the NRXN1 gene may underlie the disease in this patient.
To detect potential mutations of HEXB gene in an infant with Sandhoff disease (SD). Genomic DNA was extracted from peripheral blood sample of the infant. All coding exons (exons 1 to 14) and splicing sites of the HEXB gene were subjected to PCR amplification and direct sequencing.PubMed Protein BLAST system was employed to analyze cross-species conservation of the mutant amino acid. PubMed BLAST CD-search was performed to identify functional domains destroyed by thecandidate mutations. Impact of the mutations was analyzed with software including PolyPhen-2, Mutation Taster and SIFT. Whole-exome sequencing was carried out to identify additional mutations. The infant was found to carry compound heterozygous mutations c.1652G>A(p.Cys551Tyr) and c.1389C>G (p.Tyr463*) of the HEXB gene. The c.1389C>G (p.Tyr463*) mutation may lead to destruction of two functional domains in β subunit of the Hex protein. The c.1652G>A(p.Cys551Tyr) mutation, unreported previously,was predicted to be probably damaging by Bioinformatic
To determine the CGG repeat number and methylation status of FMR1 gene for fetuses whose mothers have carried a FMR1 mutation. For 30 pregnant women, the fetal CGG repeat number was determined with a GC-rich PCR system by using chorionic villus, amniotic fluid or umbilical blood samples. The methylation status of the FMR1 gene was confirmed with Southern blotting. In total 30 prenatal diagnoses were performed for 29 carriers of FMR1 gene mutations and 1 with FMR1 gene deletion mosaicism. Three fetuses were found to carry premutations, 9 were with full mutations and 1 with mosaicism of premutation and full mutations. Eighteen fetuses were normal. Considering the genetic complexity of Fragile X syndrome (FXS), single method may not suffice accurate determination of their genetic status. The pitfalls and technical limitations of protocols requires adoption of personalized strategy for its prenatal diagnosis.