Child ; Developmental Disabilities/genetics* ; Frameshift Mutation ; Humans ; Seizures/genetics* ; Seizures, Febrile/genetics* ; Semaphorins/genetics*

OBJECTIVE: To explore the genetic basis for a patient with Dilated cardiomyopathy. METHODS: A patient admitted to Beijing Anzhen Hospital Affiliated to Capital Medical University in April 2022 was selected as the study subject. Clinical data and family history of the patient was collected. Targeted exome sequencing was carried out. Candidate variant was verified by Sanger sequencing and bioinformatic analysis based on guidelines of the American College of Medical Genetics and Genomics (ACMG). RESULTS: DNA sequencing revealed that the patient has harbored a heterozygous c.5044dupG frameshift variant of the FLNC gene. Based on the ACMG guidelines, the variant was predicted to be likely pathogenic (PVS1+PM2_Supporting+PP4). CONCLUSION The heterozygous c.5044dupG variant of the FLNC gene probably underlay the pathogenesis in this patient, which has provided a basis for the genetic counseling for his family.
Humans ; Cardiomyopathy, Dilated/genetics* ; Genetic Testing ; Genetic Counseling ; Computational Biology ; Frameshift Mutation ; Mutation ; Filamins

We present a case of severe persisting unconjugated hyperbilirubinemia in a Uigur infant boy, eventually diagnosed as Crigler-Najjar syndrome type I. DNA analysis of his blood of the UGT1A1 gene sequence demonstrated that he was homozygous for an insertion mutation causing a change of the coding exons with a frame-shift, resulting in the substitution of 27 abnormal amino acid residues in his hepatic bilirubin uridine diphosphoglucuronyl transferase enzyme. Both of his parents were heterozygous for the same mutation. A novel frame-shifting mutation of the UGT1A1 gene was found, confirming the diagnosis of Crigler-Najjar syndrome type I for this patient.
Crigler-Najjar Syndrome ; diagnosis ; genetics ; Frameshift Mutation ; genetics ; Glucuronosyltransferase ; genetics ; Humans ; Infant, Newborn ; Male

High-throughput sequencing was performed for the peripheral blood DNA from two probands in the family with tuberous sclerosis complex (TSC) to determine the sequences of TSC-related genes TSC1 and TSC2 and their splicing regions and identify mutation sites. Amplification primers were designed for the mutation sites and polymerase chain reaction and Sanger sequencing were used to verify the sequences of peripheral blood DNA from the probands and their parents. The two probands had c.3981-3982 insA (p.Asp1327AspfsX87) and c.4013-4014 delCA (p.Ser1338Cysfs) heterozygous mutations, respectively, in the TSC2 gene. The parents of proband 1 had no abnormalities at these two loci; the mother of proband 2 had c.4013-4014 delCA heterozygous mutation in the TSC2 gene, while the father and the grandparents of proband 2 had no abnormalities. c.3981-3982 insA mutation may cause early coding termination of amino acid sequence at the 1413th site, and c.4013-4014 delCA mutation may cause early coding termination of amino acid sequence at the 1412th site. These two mutations are the pathogenic mutations for families 1 and 2, respectively, and both of them are novel frameshift mutations, but their association with the disease needs to be further verified by mutant protein function cell model and animal model.
Child ; Child, Preschool ; Female ; Frameshift Mutation ; Humans ; Tuberous Sclerosis ; genetics ; Tumor Suppressor Proteins ; genetics

Inherited afibrinogenemia is a rare autosomal recessive bleeding disease characterized by complete absence of fibrinogen in blood. To identify the genotype in a Chinese family with inherited afibrinogenemia, the samples of peripheral blood were collected from 6 members of 3 generations. The activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and fibrinogen (Fg, clauss) were tested. Fg was also analyzed by using immunoturbidimetry method. DNAs of six members were extracted by using a DNA extract kit. All the exons and exon-intron boundaries of the three fibrinogen genes were amplified by using PCR and analyzed by direct sequencing. The results showed that the parents of proband were 3 degree consanguinity. A homozygous c.934_935insA in FGA was found in proband which results in the change of protein p.Ser312fsX42. The parents, grandmother, maternal grandmother and father's sister were all detected with heterozygous mutation which was same as that in proband. In conclusion homozygous c.934_935insA in FGA is a cause of inherited afibrinogenemia and a novel mutation being reported.
Afibrinogenemia ; etiology ; genetics ; Child ; Exons ; Female ; Fibrinogen ; genetics ; Frameshift Mutation ; Heterozygote ; Humans ; Male ; Pedigree

OBJECTIVETo investigate the genetic defect and its mechanism in a patient with congenital afibrinogenemia.

METHODSThe plasma fibrinogen activity and antigen of the patient was determined using the Clauss method and immuno-nephelometric assay, respectively. Genomic DNA was isolated from peripheral blood of the proband and his related family members. All exons and exon-intron boundaries of the three fibrinogen genes (FGA, FGB, FGG) were amplified by PCR followed by direct sequencing. Thrombin fibrin aggregation curve were detected in the plasma of the patient. Wild-type and mutation type fibrinogen vectors were constructed, and then transfected into COS-7 cells. The wild-type and mutant proteins from the culture media and cell lysates were tested by Western blot and ELISA.

RESULTSAPTT, PT, TT were significantly longer in the proband. Plasma fibrinogen activity and antigen of the patient could not be detected using the Clauss method and immuno-nephelometry, respectively. Gene analysis revealed that a novel homozygous GTTT insertion between nucleotides 2833 and 2834 in FGB exon 2 in the proband. The proband's father, mother, brother and son were heterozygous. The polymerization curves of the patient did not show a lag phase or final turbidity, compared with the normal controls. Western blot analysis showed the lack of complete half-molecules of the fibrinogen molecule and fibrinogen in patient's plasma under non-reducing conditions. It also could not detect the truncated Bβ chain under reducing conditions. Abnormal fibrinogen molecule (molecule weight>340 000) were found in transfected COS-7 cells by Western blot, which indicated that the mutation caused the abnormal intracellular fibrinogen molecule assembly. The fibrinogen band was absent in culture media transfected by the mutation. Fibrinogen levels of mutant fibrinogen were no significant different from those of wild-type fibrinogen in cell lysates by ELISA analysis [(2.47 ± 0.30) μg/ml vs (2.65±0.60) μg/ml, P=0.0889]; However, the levels of the mutant fibrinogen were statistically significant lower than those of wild type fibrinogen in culture media [(0.01 ± 0.01) μg/ml vs (3.80±0.80) μg/ml, P=0.0001].

CONCLUSIONCongenital afibrinogenemia was caused by this frameshift mutation in exon 2 of FGB. This novel mutation impaired fibrinogen assembly and secretion.

Afibrinogenemia ; congenital ; etiology ; genetics ; Fibrinogen ; genetics ; Frameshift Mutation ; Humans ; Male ; Mutagenesis, Insertional ; Pedigree ; Young Adult

OBJECTIVE: To explore the molecular etiology for a Chinese family with mitochondrial DNA depletion syndrome. METHODS: Genomic DNA was extracted from peripheral blood samples of the patient and her parents.Targeted capture and next-generation sequencing was carried out to detect potential variants. Suspected variant was validated by Sanger sequencing. RESULTS: A novel homozygous frameshift variant c.505_508delTATC was identified in the patient, for which both his mother and father were carriers. CONCLUSION The frameshift variant c.505_508delTATC probably underlies the mitochondrial DNA depletion syndrome in this patient. The result also enriched the variant spectrum of DGUOK gene.
Asian Continental Ancestry Group ; genetics ; DNA, Mitochondrial ; genetics ; Female ; Frameshift Mutation ; Humans ; Mutation ; Phosphotransferases (Alcohol Group Acceptor) ; genetics ; Syndrome

This study was purposed to investigate the molecular genetics basis for para-Bombay phenotype. The para-Bombay phenotype of two probands was identified by routine serological techniques. The full coding region of alpha (1, 2) fucosyltransferase gene (FUT1 and FUT2) in the probands was amplified by polymerase chain reaction and the amplified fragments were directly sequenced, meanwhile the mutations of FUT1 were also identified by TOPO TA cloning sequence method. The results indicated that two heterozygous mutations were detected by directly sequencing in two probands: AG deletion at position 547 - 552 and C to T mutation at position 658. Two different mutations were confirmed to be true compound heterozygotes with each mutation on a separate homologous chromosome by TOPO TA cloning sequence method. AG deletion at position 547 - 552 caused a reading frame shift and a premature stop codon. C658T mutation resulted in Arg-->Cys at amino acid position 220. It is suggested that the FUT1 mutation of two probands are compound heterozygous mutation with different chromosomes, which are named h1h3 and may be the genetics basis of para-Bombay phenotype.
ABO Blood-Group System ; genetics ; Alleles ; Frameshift Mutation ; Fucosyltransferases ; genetics ; Gene Deletion ; Heterozygote ; Humans ; Male ; Mutation, Missense

OBJECTIVE: To explore the genetic basis for a child with mental retardation. METHODS: Whole exome sequencing was carried out for the child. Candidate variant was screened based on his clinical features and verified by Sanger sequencing. RESULTS: The child was found to harbor a c.995_1002delAGACAAAA(p.Asp332AlafsTer84) frameshift variant in the SYNGAP1 gene. Bioinformatic analysis suggested it to be pathogenic. The same variant was not detected in either parent. CONCLUSION The c.995_1002delAGACAAAA(p.Asp332AlafsTer84) frameshift variant of the SYNGAP1 gene probably underlay the mental retardation in this child. Above finding has expanded the spectrum of SYNGAP1 gene variants and provided a basis for the diagnosis and treatment for this child.
Child ; Humans ; Intellectual Disability/genetics* ; Frameshift Mutation ; High-Throughput Nucleotide Sequencing ; Computational Biology ; Heterozygote ; Mutation ; ras GTPase-Activating Proteins/genetics*

OBJECTIVETo analyze the mutation of COL9A2 gene and investigate the molecular pathogenesis of pathological myopia in a Han Chinese population.

METHODSMutation in the coding region of the COL9A2 gene was screened by Sanger sequencing in 200 subjects with pathological myopia and 200 normal controls. The detected variants were genotyped by SNaPshot method in another 200 myopic cases and 200 normal controls.

RESULTSSanger sequencing has failed to detect the reported D281fs frameshift mutation in the 200 cases. A novel variant, c.143G>C heterozygous missense mutation in exon 2, was identified in a myopic subject, and another novel variant, c.884G>A heterozygous missense mutation in exon 17, was found in another case. Neither was found in normal controls. One SNP (rs2228564) was detected in the coding region of the COL9A2 gene, but there was no significant difference in its allelic frequencies between the two groups (P> 0.05). Genotyping of the remainder 200 cases and 200 controls by SNaPshot method has found a c.143G>C in 1 case and c.884G>A in 2 cases, though no significant difference between the two groups was detected (P> 0.05).

CONCLUSIONThe D281fs frameshift mutation in the COL9A2 gene is not associated with pathological myopia in the studied Han Chinese population. Two novel mutations, c.143G>C in exon 2 and c.884G>A in exon 17 of the COL9A2 gene, may contribute to the development of pathological myopia.

Asian Continental Ancestry Group ; genetics ; China ; ethnology ; Collagen Type IX ; genetics ; Frameshift Mutation ; Humans ; Myopia, Degenerative ; genetics ; Sequence Analysis, DNA