Analysis of Gene Detection and Hematological Phenotype of Thalassemia / 中国实验血液学杂志

OBJECTIVE@#To investigate gene mutation types of thalassemia in the population of this area and the relationship between hematological phenotype and age in β-thalassemia.@*METHODS@#1 351 suspected cases of thalassemia were detected in the First Affiliated Hospital of Chengdu Medical College from June 2017 to June 2021. PCR-reverse dot blot hybridization(PCR-RDB) technique was used to detect the common α and β thalassemia gene types, then the data of MCV, MCH, MCHC and Hb of confirmed cases were collected. The heterozygotes of β-thalassemia were divided into 0-18 year group, 19-50 year group and >50 year group according to age, and the differences of hematological phenotypes among different groups were compared.@*RESULTS@#Among the detected 1 351 samples， 523(38.71%) cases were diagnosed as thalassemia, 13 genotypes were detected in 260 cases (19.25%) with α-thalassemia; and 12 genotypes were detected in 252 cases (18.65%) with β-thalassemia; 9 genotypes were detected in 11 cases with αβ thalassemia. It was found that MCV and MCH were increased significantly in 0-18 year group, 19-50 year group and >50 year group, MCHC was highest in 0-18 year group, and Hb was the lowest in the >50 year group, and the difference was statistically significant（P<0.05）.@*CONCLUSION@#In this area, --SEA/αα was the major genotype of α-thalassemia, and CD41-42 /N and IVS-II-654/N were the major genotypes of β-thalassemia. Morever, MCV and MCH were the lowest in the 0-18 year old group and the highest in the >50 years old group in heterozygotes of β-thalassemia. The influence of age on hematological parameters in the primary screening of thalassemia provides a certain reference value in clinical diagnosis and treatment.

Molecular Epidemiological Characteristics and Differential Diagnosis of Common δβ-Thalassemia/HPFH / 中国实验血液学杂志

OBJECTIVE@#To investigate the molecular epidemiological characteristics of common δβ-thalassemia/hereditary persistence of fetal hemoglobin(HPFH) in the prepregnant population in Huadu, and to provide a laboratory basis for prevention and control of thalassemia.@*METHODS@#Blood samples of childbearing age people in Huadu District of Guangzhou who participated in free thalassemia testing from January 2016 to July 2021 were collected for hematological parameters analysis and hemoglobin electrophoresis. Chinese Gγ+(Aγδβ)0-thalassemia, SEA-HPFH and Taiwanese deletion β-thalassemia were detected by Gap-PCR in the samples with higher HbF(≥5%). Primers were designed for the proximal HBG1 and HBG2 promoter, and the point mutations in the proximal promoter region were detected by Sanger sequencing. Hematology parameters data were statistically analyzed.@*RESULTS@#Among 27 088 samples, Thirteen cases of Chinese Gγ+(Aγδβ)0-thalassemia and thirty-three cases of SEA-HPFH were detected, which including 3 cases of Chinese Gγ+(Aγδβ)0/βN compounded with --SEA/αα and three cases of SEA-HPFH/βN compounded with --SEA/αα. 6 carriers with Aγ-196 C>T were also detected; No Taiwanese thalassemia genetype was detected. The total detection rate of common δβ-thalassemia/HPFH was 0.19% (52/27 088). There were significant differences in the levels of MCV, MCH, HbA2, and HbF among Chinese Gγ+(Aγδβ)0-thalassemia, SEA-HPFH, Aγ-196 C>T (P<0.001). The hematological parameters of Aγ-196C>T combined with α0-thalassemia were similar to those of Chinese Gγ+(Aγδβ)0-thalassemia carriers, and only HbA2 was significantly lower than that of the latter, which was helpful for clinical identification.@*CONCLUSION@#δβ-thalassemia/HPFH should be included in the scope of thalassemia prevention program in the prepregnant population in Huadu District, and hematological parameters can provide some basis for identifying different types of δβ-thalassemia/HPFH.

Analysis of TSC2 gene variant in a neonate with tuberous sclerosis complex / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical characteristics and genetic variant in a neonate with tuberous sclerosis complex (TSC).@*METHODS@#Clinical data of the neonate was collected. Genomic DNA was extracted from peripheral blood samples of the child and his parents and subjected to next-generation sequencing (NGS).@*RESULTS@#The child was noted to have yellowish hair upon birth. NGS revealed that he has harbored a heterozygous c.3914del (p.P1305Rfs*20) frameshifting variant of the TSC2 gene. The variant has probably caused premature termination of translation, resulting in a truncated protein.@*CONCLUSION@#Yellowish hair has rarely been described as the first manifestation of TSC. The c.3914del (p.P1305Rfs*20) variant of the TSC2 gene probably underlay the TSC in this patient.

Meta-analysis for the association of GJB2 gene p.V37I variant and its types with the risk of deafness / 中华医学遗传学杂志

OBJECTIVE@#To assess the association of c.109G>A (p.V37I) variant of the GJB2 gene and its types with the risk of deafness.@*METHODS@#PubMed, Embase, Cochrane Library, CNKI, Wanfang, and VIP database were searched for cases with GJB2 gene c.109G>A (p.V37I) variant and its compounds with variants of other sites from case-control studies, cohort studies and cross-sectional studies. The search time was from the establishment of database to April 2021. Two researchers have independently screened the literature according to the inclusion and exclusion criteria, extracted the data, and evaluated the included studies according to the criteria. Stata 12.0 software was used for the meta-analysis and publication bias analysis, and a sensitivity analysis was also carried out when necessary.@*RESULTS@#A total of 22 articles (17 in English and 5 in Chinese) were included. There were 7455 cases in the deafness group and 10 464 cases in the control group. The results of meta-analysis showed the c.109G>A (p.V37I) variant to be strongly associated with the risk of deafness (OR: 3.56, 95%CI: 2.31-5.47, P < 0.001). Analysis based on the mutational type also suggested c.109G>A (p.V37I) homozygosity (OR: 11.36, 95%CI: 5.93-21.74, P < 0.001) and compound loss of heterozygosity mutations (OR: 9.27, 95%CI: 3.97-21.64, P < 0.001) to be strongly associated with the risk of deafness. By contrast, heterozygous c.109G>A (p.V37I) variant (OR: 1.20, 95%CI: 0.72-2.00, P = 0.478) and compound heterozygous missense mutation (OR: 1.54, 95%CI: 0.98-2.44, P = 0.063) are not strongly associated with the risk.@*CONCLUSION@#The homozygous c.109G>A (p.V37I) variants of the GJB2 gene and its compound deletional mutation with another GJB2 allele can significantly increase the risk of deafness. Heterozygous c.109G>A (p.V37I) variant of the GJB2 gene or its compound with a missense mutation of another GJB2 allele do not increase the risk.

Para-Bombay phenotype due to bi-allelic heterozygous base deletions of FUT1 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic mechanism underlying a case with para-Bombay phenotype.@*METHODS@#The ABO and Lewis phenotype were identified with serological methods. The coding regions of exons 6 and 7 of the ABO and FUT1 genes were amplified with PCR and directly sequenced. Haploid sequence analysis was carried out on the variant sites of the FUT1 gene.@*RESULTS@#Serological analysis confirmed that the proband has a rare para-Bombay phenotype. Direct sequencing revealed that he was a B.01/O.01.02 heterozygote for the ABO gene, and had heterozygous deletion for the 768 and 881-882 sites of the FUT1 gene. Further haploid analysis showed that the c.881_882delTT deletion has occurred in one haploid while c.768delC was present in the other haploid. The proband was therefore determined as a FUT1*01N.13/01N.20 heterozygote, which have resulted in frameshift in polypeptide chain p.Phe294Cysfs*40 and p.Val257Phefs*23, respectively.@*CONCLUSION@#A rare bi-allelic heterozygous deletion of para-Bombay phenotype has been identified in a blood donor. The c.881_882delTT and c.768delC deletions may decrease the activity of α-1,2-fucosyltransferase.

Analysis of novel compound heterozygous variants of the GJA8 gene in a child with congenital cataract / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for child with congenital cataract.@*METHODS@#The child was subjected to next-generation sequencing. Candidate variant was verified by Sanger sequencing of his family members.@*RESULTS@#The proband was found to harbor novel heterozygous variants of c.855del and c.872dup of the GJA8 gene, which were inherited from his father and mother, respectively. Neither of these two variants has been reported. Based on the American College of Medical Genetics and Genomics (ACMG) guidelines, the c.855del and c.872dup variants were classified as likely pathogenic (PVS1_S+PM2+PP4) and pathogenic (PVS1_S+PM2+PM3+PP4), respectively.@*CONCLUSION@#The c.855del and c.872dup variants of the GJA8 gene probably underlay the congenital cataract in this patient.

Identification of novel variants in a Chinese patient with Chediak-Higashi syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child featuring Chediak-Higashi syndrome (CHS).@*METHODS@#Clinical manifestations and results of auxiliary examination of the proband were analyzed. The proband was subjected to whole exome sequencing, and the results were verified by Sanger sequencing. Correlation between the genotype and clinical phenotype was analyzed.@*RESULTS@#The proband showed partial skin albinism, recurrent respiratory infection and other immune deficiencies. Genetic testing showed that he has harbored c.2437C>T (p.Arg813*) and c.6077dupA (p.Tyr2026fs) (NM_000081) compound heterozygous variants of the LYST gene, for which his parents were both carriers. Neither variant was reported previously. HEAT repeats domain was frequently associated with more severe phenotype of CHS (81.6%), whilst no variant has been found in the PH_BEACH domain.@*CONCLUSION@#This study has enriched the spectrum of LYST gene variants associated with CHS and enabled clinical diagnosis, prenatal diagnosis and prognostic evaluation for the child.

Analysis of an ABO subtype with a novel variation / 中华医学遗传学杂志

OBJECTIVE@#To analyze the molecular characteristics of a ABO subgroup.@*METHODS@#The ABO phenotype was determined with the tube method. Exons of the ABO gene were analyzed by Sanger sequencing, and haplotypes of exons 6 and 7 were analyzed by cloning sequencing.@*RESULTS@#By forward typing, the red blood cells showed 3+ agglutination reaction with anti-A and 4+ agglutination with anti-B. A weak reaction with A1 cells and no agglutination reaction with B, O cells by the reverse typing. Sequencing results showed heterozygosity including c.297A>G, c.467C>T, c.526C>G, c.608A>G, c.657C>T, c.703G>A, c.796C>A, c.803G>C, c.930G>A. Cloning sequencing revealed a c.608A>G variant in the A allele compared with the ABO*A1.02.@*CONCLUSION@#A new variant site of subtype A of c.608G variation has been identified.

Analysis of a child with X-linked mental retardation due to a de novo variant of DDX3X gene / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical characteristics and genetic variant of a child featuring X-linked mental retardation.@*METHODS@#Whole exome sequencing and Sanger sequencing were used for the detection of variant and pedigree validation, respectively. Clinical manifestation of patients with DDX3X gene variants were also reviewed.@*RESULTS@#The child was found to harbor a heterozygous NM_001193416.3: c.1332_1333delCT (p.Leu445Serfs*19) variant of the DDX3X gene. The same variant was not found in either of her parents.@*CONCLUSION@#The child was diagnosed with X-linked mental retardation due to variant of the DDX3X gene. Above finding has enriched the spectrum of DDX3X gene variants and provided a basis for clinical diagnosis and prenatal diagnosis for this pedigrees.

The phenotypes and genotypes of four patients with Dubin-Johnson syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic etiology in four patients with hyperbilirubinemia, and discuss the correlation between clinical characteristics and molecular basis.@*METHODS@#The data of clinical manifestation and auxiliary examinations were collected. Genomic DNA of the four patients was extracted and analyzed by next-generation sequencing using the panel including genes involved in hereditary metabolic liver diseases. Suspected variants were verified by Sanger sequencing.@*RESULTS@#All of the four patients were males with normal liver enzymes. It was revealed that all the patients had heterozygous variants, among which c.3011C>T, c.2443C>T and c.2556del were the variants which have not been reported previously.@*CONCLUSION@#All of the patients were diagnosed as Dubin-Johnson syndrome (DJS) caused by ABCC2 gene variants. The novel variants add to the spectrum of genetic variants of the disease. Because of the favorite prognosis, precise diagnosis can greatly reduce the psychological pressure of patients and avoid excessive treatments. At the same time, it could provide pertinent genetic counseling for the families.

Analysis of TNPO3 gene variant and clinical phenotype in a neonate with limb-girdle muscular dystrophies form 1F / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a neonate featuring developmental delay.@*METHODS@#Clinical examination and laboratory tests were carried out for the patient. Peripheral venous blood samples of the proband and his parents were extracted and subjected to target capture next generation sequencing. Candidate variant was verified by Sanger sequencing.@*RESULTS@#The patient, a four-month-old male, has presented with developmental delay and weakness of limbs. Genetic testing revealed that he had harbored a novel c.1432C>T variant of the TNPO3 gene, which was inherited from his mother. The nonsense variant has resulted in premature termination of protein translation and was predicted to be pathogenic by bioinformatics analysis.@*CONCLUSION@#The heterozygous c.1432C>T variant of the TNPO3 gene probably underlay the limb-girdle muscular dystrophies form 1F in this patient. Above finding has enriched the variation spectrum of the TNPO3 gene.

Analysis of A Pedigree with Hereditary Coagulation Factor Ⅻ Deficiency Caused by Compound Heterozygous Mutations / 中国实验血液学杂志

OBJECTIVE@#To analysis clinical phenotype and potential genetic cause of a family affected with hereditary coagulation factor Ⅻ deficiency.@*METHODS@#The prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), D-Dimer (D-D), coagulation factor Ⅻ activity (FⅫ:C) and coagulation factor Ⅻ antigen (FⅫ:Ag) were determined for phenotype diagnosis of the proband and his family members(3 generations and 5 people). Targeted capture and whole exome sequencing were performed in peripheral blood sample of the proband. Possible disease-causing mutations of F12 gene were obtained and further confirmed by Sanger sequencing. The corresponding mutation sites of the family members were analyzed afterwards. The online bioinformatics software AutoPVS1 and Mutation Taster was used to predict the effects of mutation sites on protein function.@*RESULTS@#The APTT of the proband was significantly prolonged, reaching 180.9s. FⅫ:C and FⅫ:Ag of the proband was significantly reduced to 0.8% and 4.17%, respectively. The results of whole exome sequencing displayed that there were compound heterozygous mutations in F12 gene of the proband, including the c.1261G＞T heterozygous nonsense mutation in exon 11 (causing p.Glu421*) and the c.251dupG heterozygous frameshift mutation in exon 4 (causing p.Trp85Metfs*53). Both mutations are loss of function mutations with very strong pathogenicity, leading to premature termination of the protein. AutoPVS1 and Mutation Taster software predicted both mutations as pathogenic mutations. The results of Sanger sequencing revealed that c.1261G＞T heterozygous mutation of the proband was inherited from his mother, for which his brother and his daughter were c.1261G＞T heterozygous carriers. Genotype-phenotype cosegregation was observed in this family.@*CONCLUSION@#The c.1261G＞T heterozygous nonsense mutation in exon 11 and the c.251dupG heterozygous frameshift mutation in exon 4 of the F12 gene probably account for coagulation factor Ⅻ deficiency in this family. This study reports two novel pathogenic F12 mutations for the first time worldwide.

Clinical Diagnosis and Prenatal Screening of Hb Lepore-BW Associated with IVS-II-654 Heterozygous Mutation / 中国实验血液学杂志

OBJECTIVE@#To identify one case of rare Hb Lepore-BW associated with IVS-II-654 heterozygous mutation in Sichuan area.@*METHODS@#The blood routine examination and hemoglobin electrophoresis methods were used to analyze the blood routine parameters, HbA2 and HbF in the samples of peripheral blood in proband and his parents, as well as the cord blood of pregnant woman. The detection of thalassemia gene and Sanger sequencing methods were used to detect the hemoglobin mutations.@*RESULTS@#The result showed that the Hb Lepore-BW heterozygous mutation was detected in the father of the proband, while a rare Hb Lepore-BW with IVS-II-654 heterozygous mutation was detected in the proband, as well as his mother and cord blood were both detected as IVS-II-654 heterozygous mutation.@*CONCLUSION@#The study identified a rare Hb Lepore-BW with IVS-II-654 heterozygous mutation, which was characterized by intermediate β-thalassemia. It is necessary to hemoglobin electrophoresis combined with routine blood testing in prenatal screening.

Genetic Mutation Characteristics of Glucose-6-Phosphate Dehydrogenase Deficiency Patients in Wuhan / 中国实验血液学杂志

OBJECTIVE@#To explore the genotype mutation characteristics of patients with glucose-6-phosphate dehydrogenase(G6PD) deficiency in Wuhan.@*METHODS@#A total of 1 321 neonates with positive screening and outpatients were received G6PD mutation detection, 12 kinds of common G6PD mutation in Chinese people was detected by using multicolor melting curve analysis (MMCA) method, for those with negative results, the enzyme activity and clinical information were analyzed, sequencing was recommended after informed consent when it is necessary.@*RESULTS@#Among 1321 patients, a total of 768 mutations were detected out, with a detection rate of 58.1%. A total of 18 types of G6PD genotypes were identified, including c.1388G>A, c.1376G>T, c.95G>A, c.1024C>T, c.871G>A, c.392G>T, c.487G>A, c.1360C>T, c.1004C>A, c.517T>C, c.592C>T, c.94C>G, c.152C>T, c.320A>G, c.1028A>G, c.1316G>A, c.1327G>C and c.1376G>C, including 683 male hemizygotes, 3 female homozygotes, 80 female heterozygotes and 2 female compound heterozygous.@*CONCLUSION@#A total of 18 types of G6PD mutations are identified in the reaserch, and c.94C>G, c.1028A>G and c.1327G>C are first reported in Chinese population. The most common G6PD mutation types in Wuhan are c.1388G>A, c.1376G>T, c.95G>A.

Study on Thalassemia in Han Population in Sanya of Hainan Province / 中国实验血液学杂志

OBJECTIVE@#To study the distribution characteristics of thalassemia genotype in Han Population in Sanya of Hainan Province.@*METHODS@#Gap PCR and reverse dot hybridization were used to detect and analyze the thalassemia gene in 572 suspected thalassemia carriers of Han Population in Sanya.@*RESULTS@#Among the 572 Han Population in Sanya, 271 cases of thalassemia gene abnormality were detected, among which 161 cases were founded to be carriers of α-thalassemia gene. A total of 9 genotypes were detected, in the following order of the detection rate was －－SEA/αα，－α3.7/αα，－α4.2/αα，－－SEA/－α3.7，－－SEA/－α4.2，－α4.2/－α4.2，－α3.7/－α4.2，－α3.7/－α3.7，－－SEA/－－SEA. Among them, the deletion type (－－SEA/αα) in southeast Asia was the most common, accounting for 66 cases. 99 cases of β-thalassemia were detected, there were 7 genotypes, all of which were heterozygous. The order of the detection rate was CD41-42/βN, IVS-II-654/βN, CD17/βN, CD71-72/βN, -28/βN, －29/βN, CD27-28/βN. Among them, CD41-42/βN was the most common, accounting for 51 cases. In addition, 11 cases of combined α and β thalassemia were detected. Five kinds of genotypes were checked out, the order of detection rate was －α3.7/αα composite CD41-42/βN, －－SEA/αα composite IVS-II-654/βN, －α4.2/－α4.2 composite CD41-42/βN, －α4.2/αα composite －29/βN , －－SEA/ －α4.2 composite CD41-42/βN.@*CONCLUSION@#Han Population in Sanya of Hainan Province is a high-risk population of thalassemia, the genotype characteristics are different from other areas with high incidence of thalassemia in China. The main type of α-thalassemia is the deficiency mutation of southeast Asia, while CD41-42 heterozygous mutation is the main type of β-thalassemia.

Clinical and genetic analysis of a child with mental retardation autosomal dominant 7 / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical and genetic characteristics of a child with clinical manifestations of hypoplasia, epilepsy and abnormal face.@*METHODS@#The clinical data of the child were collected. The peripheral blood samples of the patient and his parents were extracted for high-throughput sequencing, and Sanger sequencing verification and bioinformatics analysis were performed to detect suspected pathogenic variants.@*RESULTS@#The clinical manifestations of the child were overall developmental backwardness, seizures, autism, and special facial appearance. High throughput sequencing showed that there was a heterozygous mutation of exon 11: c.1920_c.1927delCCTCTACC (p.Ser641Rfs*31) of the DYRK1A gene. The same variant was found in neither of her parents, suggesting that it has a denovo origin.@*CONCLUSION@#The exon11: c.1920_c.1927delCCTCTACC (p.Ser641Rfs*31) mutation in DYRK1A gene was the genetic etiology of the case, which enriches the pathogenic gene spectrum of DYRK1A and provides the basis for clinical diagnosis and genetic counseling.

Genetic diagnosis of 3 families with choroideremia / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical manifestations and causative gene variants of the choroideremia patients, and to help the patients bedifferential diagnosed by whole exome sequencing and provide theoretical basis for their genetic counseling.@*METHODS@#Clinical data of 3 families were collected and genomic DNA was extracted respectively from peripheral blood of patients and related subjects. Exome targeted sequencing was used to screen suspicious gene mutations. Sanger sequencing and quantitative PCR were used to verify the candidate mutations and investigate the mutation carrying status of other members of the family. The candidate mutations were searched through HGMD and PubMed databases for the pathogenicity reports, and the pathogenicity of candidate mutations was judged according to a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology.@*RESULTS@#The proband of family 1 is c.1584_1587del (p.Val529Hisfs*6) variant hemizygote, whose daughter carries c.1584_1587del (p.Val529Hisfs*6) heterozygous variation. The proband of family 2 is a hemizygote with deletion of exons 10 to 15 (E10-15del), and her mother and sister carry the E10-15del heterozygous variation. In family 3, the proband is c.544delT (p.Cys182Valfs*14) variant hemizygote, and his mother is c.544delT (p.Cys182Valfs*14) heterozygote, but the father do not detect this variant. All the 3 families were detected pathogenic gene variations of CHM, two of which were known pathogenic variation and one of which was novel CHM gene c.544delT (p.C182Vfs*14) in this study. The c.544delT frameshift mutation of CHM gene can lead to the premature termination of the product protein translation and nonfunctioning protein. It is a pathogenic mutation according to ACMG guidelines.@*CONCLUSION@#The findings of this study expand the gene variation spectrum of choroideremia.

Analysis of ADNP gene variant in a child with Helsmoortel-van der Aa syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child manifesting with intellectual disability, language delay and autism spectrum disorder.@*METHODS@#Genomic DNA was extracted from peripheral blood samples of the child and his family members, and subjected to whole exome sequencing. Candidate variants were verified by Sanger sequencing and interpreted according to the guidelines of the American College of Medical Genetics and Genomics.@*RESULTS@#The child was found to harbor a heterozygous c.568C>T (p.Q190X) nonsense variant of the ADNP gene, which was not detected in either parent by Sanger sequencing.@*CONCLUSION@#The clinical and genetic testing both suggested that the child has Helsmoortel-van der Aa syndrome due to ADNP gene mutation, which is extremely rare in China.

Analysis of IQSEC2 gene variant in a child with X-linked mental retardation / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical phenotype and genetic variants of a child with X-linked mental retardation caused by IQSEC2 gene mutation, and provide reference for the diagnosis of the disease.@*METHODS@#The child was subjected to next generation sequencing (NGS), and the diagnosis was made by taking consideration of her clinical characteristics.@*RESULTS@#The child has presented with global developmental delay, particularly in fine motor skill and language development, in addition with intellectual disability. Genetic testing revealed that she has harbored a heterozygous c.1861dup variant of the IQSEC2 gene, which was not detected in either parent.@*CONCLUSION@#The de novo c.186ldup variant of the IQSEC2 gene probably underlay the X-linked mental retardation in this child. Above finding has, expanded the spectrum of IQSEC2 gene mutations and provide a basis for the diagnosis of similar cases.

Clinical and genetic analysis of two patients with CHARGE syndrome due to de novo variants of CHD7 gene / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical characteristics and genetic basis of two children patients with CHARGE syndrome.@*METHODS@#The clinical features of the two patients were analyzed, and potential variants were detected by Trio whole exome sequencing (trio-WES) of the probands and their parents.@*RESULTS@#Child 1 has manifested cerebellar vermis dysplasia, enlargement of cerebral ventricles, whereas child 2 manifested with infantile spasm and congenital hip dysplasia. Both children were found to harbor de novo heterozygous variants of the CHD7 gene, namely c.4015C>T (exon 17) and c.5050G>A (exon 22). Based on the guidelines of the American College of Medical Genetics and Genomics, the two variants were rated as pathogenic variants, and the related disease was CHARGE syndrome. Furthermore, child 2 was also found to harbor a novel heterozygous c.6161A>C (p.Gln2054Pro) missense variant of COL12A1 gene, which was rated as possibly pathogenic, and the associated disease was Bethlem myopathy type 2, which is partially matched with the patient' s clinical phenotype.@*CONCLUSION@#The special clinical phenotypes shown by the two children harboring novel CHD7 variants have further expanded the phenotypic spectrum of CHARGE syndrome.