RESUMO
Recurrent proximal 16p11.2 deletion (16p11.2del) is a risk factor for diverse neurodevelopmental disorders with incomplete penetrance and variable expressivity. Although investigation with human induced pluripotent stem cell models has confirmed disruption of neuronal development in 16p11.2del neuronal cells, which genes are responsible for abnormal cellular phenotypes and what determines the penetrance of neurodevelopmental abnormalities are unknown. We performed haplotype phasing of the 16p11.2 region in a 16p11.2del neurodevelopmental disorders cohort and generated human induced pluripotent stem cells for two 16p11.2del families with distinct residual haplotypes and variable neurodevelopmental disorder phenotypes. Using transcriptomic profiles and cellular phenotypes of the human induced pluripotent stem cell-differentiated cortex neuronal cells, we revealed MAPK3 to be a contributor to dysfunction in multiple pathways related to early neuronal development, with altered soma and electrophysiological properties in mature neuronal cells. Notably, MAPK3 expression in 16p11.2del neuronal cells varied on the basis of a 132 kb 58 single nucleotide polymorphism (SNP) residual haplotype, with the version composed entirely of minor alleles associated with reduced MAPK3 expression. Ten SNPs on the residual haplotype were mapped to enhancers of MAPK3. We functionally validated six of these SNPs by luciferase assay, implicating them in the residual haplotype-specific differences in MAPK3 expression via cis-regulation. Finally, the analysis of three different cohorts of 16p11.2del subjects showed that this minor residual haplotype is associated with neurodevelopmental disorder phenotypes in 16p11.2del carriers.
Assuntos
Deleção Cromossômica , Células-Tronco Pluripotentes Induzidas , Humanos , Haplótipos , Fenótipo , Diferenciação CelularRESUMO
BACKGROUND: Trisomy 18 syndrome, also called Edwards syndrome, is the second most common autosomal trisomy after trisomy 21 that is caused by the presence of an extra copy of chromosome 18. Approximately 50% of infants with trisomy 18 cannot survive for more than 1 week and about 5 - 10% of children die within 1 year after birth. The aim of this study is to describe a 4-year-old female patient of mosaic trisomy 18 with normal prenatal ultrasound findings and maternal serum markers and to investigate the relationship between the percentage of trisomic cells and the major clinical phenotypes combined with other nine patients through a review of the literature. METHODS: The patient's peripheral blood was examined by cytogenetic G-banding technique. RESULTS: The cytogenetics results reported following the ISCN 2020 guideline as mos 47,XX,+18[87]/46,XX[13]. CONCLUSIONS: There is little correlation between various phenotypes of mosaic trisomy 18 and the percentage of trisomy cells in the patient's peripheral leukocytes. Although most of fetuses with mosaic trisomy 18 have abnormal ultrasound findings, it is necessary to highlight the possibility of normal findings during the pregnancy.
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Amniocentese , Diagnóstico Pré-Natal , Gravidez , Feminino , Humanos , Amniocentese/métodos , Síndrome da Trissomía do Cromossomo 18 , Trissomia , Mosaicismo , FenótipoRESUMO
Genome sequencing (GS) has been used in the diagnosis of global developmental delay (GDD)/intellectual disability (ID). However, the performance of GS in patients with inconclusive results from chromosomal microarray analysis (CMA) and exome sequencing (ES) is unknown. We recruited 100 pediatric GDD/ID patients from multiple sites in China from February 2018 to August 2020 for GS. Patients have received at least one genomic diagnostic test before enrollment. Reanalysis of their CMA/ES data was performed. The yield of GS was calculated and explanations for missed diagnoses by CMA/ES were investigated. Clinical utility was assessed by interviewing the parents by phone. The overall diagnostic yield of GS was 21%. Seven cases could have been solved with reanalysis of ES data. Thirteen families were missed by previous CMA/ES due to improper methodology. Two remained unsolved after ES reanalysis due to complex variants missed by ES, and a CNV in untranslated regions. Follow-up of the diagnosed families revealed that nine families experienced changes in clinical management, including identification of targeted treatments, cessation of unnecessary treatment, and considerations for family planning. GS demonstrated high diagnostic yield and clinical utility in this undiagnosed GDD/ID cohort, detecting a wide range of variant types of different sizes in a single workflow.
Assuntos
Deficiência Intelectual , Criança , Deficiências do Desenvolvimento/diagnóstico , Deficiências do Desenvolvimento/genética , Humanos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/genética , Análise em Microsséries/métodos , Estudos Prospectivos , Sequenciamento do ExomaRESUMO
OBJECTIVE: To assess the value of chromosomal karyotyping analysis and single nucleotide polymorphism-based microarray (SNP-array) for the detection of chromosomal mosaicisms in amniotic fluid samples. METHODS: Seventy four pregnant women with fetal mosaicisms detected by both methods were retrospectively analyzed. RESULTS: Among the 74 mosaicisms, 12 were pseudo and 62 were true mosaicisms, which included 1 Robertsonian translocation, 3 deletions, 4 supernumerary markers, 19 autosomal aneuploidy mosaicisms, 30 sex chromosome aneuploidy mosaicisms and 5 isometric chromosome mosaicisms. CONCLUSION: Chromosome karyotyping analysis and SNP-array have their own advantages and limitations for the diagnosis of mosaicisms. When the two methods have yielded inconsistent results, fluorescence in situ hybridization may be used for further verification.
Assuntos
Mosaicismo , Diagnóstico Pré-Natal , Aneuploidia , Aberrações Cromossômicas , Feminino , Humanos , Hibridização in Situ Fluorescente , Gravidez , Diagnóstico Pré-Natal/métodos , Estudos Retrospectivos , Aberrações dos Cromossomos SexuaisRESUMO
OBJECTIVES: To study the characteristics of amino acid metabolism in preterm infants in Guangxi, China. METHODS: A retrospective analysis was performed on the medical data of 30 757 neonates who underwent the screening for inherited metabolic diseases and had negative results in Guangxi Neonatal Disease Screening Center from 2018 to 2020. Among these neonates, there were 28 611 normal full-term infants (control group) and 2 146 preterm infants (preterm birth group). According to gestational age, the preterm infants were further divided into four groups: very preterm (n=209), moderately preterm (n=307), and late preterm group (n=1 630). According to birth weight, they were divided into three groups: very low birth weight group (n=161), low birth weight group (n=1 085), and normal birth weight group (n=900). According to blood collection time, they were divided into three groups: 3-7 days group (n=1 664), 8-14 days group (n=314) and 15-28 days group (n=168). Tandem mass spectrometry was performed to measure the levels of 11 amino acids in dried blood spots, which were then compared between groups. RESULTS: After adjustment for confounding factors, there were significant differences in the levels of 11 amino acids among different gestational age groups (P<0.05), and significant differences were observed in the levels of the 11 amino acids between the control group and the various preterm groups (except for citrulline and methionine in the late preterm group). There were significant differences in the levels of 11 amino acids among different birth weight groups (P<0.05). Except for ornithine, there were significant differences in the levels of other amino acids among the different blood collection time groups (P<0.05). CONCLUSIONS: Gestational age, birth weight and blood collection time all affect amino acid metabolism in preterm infants in Guangxi, China. This provides a basis for the laboratory to establish the reference standard and clinical interpretation of blood amino acid levels in preterm infants, and to improve the nutritional metabolism of preterm infants.
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Recém-Nascido Prematuro , Nascimento Prematuro , Aminoácidos , China , Idade Gestacional , Humanos , Lactente , Recém-Nascido , Recém-Nascido de muito Baixo Peso , Estudos RetrospectivosRESUMO
PURPOSE: To examine the overall genomic copy-number variant (CNV) landscape of Chinese pediatric patients with developmental disorders. METHODS: De-identified chromosomal microarray (CMA) data from 10,026 pediatric patients with developmental disorders were collected for re-evaluating the pathogenic CNV (pCNV) yields of different medical conditions and for comparing the frequency and phenotypic variability of genomic disorders between the Chinese and Western patient populations. RESULTS: The overall yield of pCNVs in the Chinese pediatric patient cohort was 21.37%, with variable yields for different disorders. Yields of pCNVs were positively associated with phenotypic complexity and intellectual disability/developmental delay (ID/DD) comorbidity for most disorders. The genomic burden and pCNV yield in neurodevelopmental disorders supported a female protective effect. However, the stratification analysis revealed that it was seen only in nonsyndromic ID/DD, not in nonsyndromic autism spectrum disorders or seizure. Furthermore, 15 known genomic disorders showed significantly different frequencies in Chinese and Western patient cohorts, and profiles of referred clinical features for 15 known genomic disorders were also significantly different in the two cohorts. CONCLUSION: We defined the pCNV yields and profiles of the Chinese pediatric patients with different medical conditions and uncovered differences in the frequency and phenotypic diversity of genomic disorders between Chinese and Western patients.
Assuntos
Deficiências do Desenvolvimento , Deficiência Intelectual , Criança , China/epidemiologia , Aberrações Cromossômicas , Variações do Número de Cópias de DNA/genética , Deficiências do Desenvolvimento/epidemiologia , Deficiências do Desenvolvimento/genética , Feminino , Humanos , Deficiência Intelectual/epidemiologia , Deficiência Intelectual/genéticaRESUMO
OBJECTIVE: To analyze the metabolic profile and genetic variants for newborns with primary carnitine deficiency (PCD) from Guangxi, China. METHODS: From January 2014 to December 2019, 400 575 newborns from the jurisdiction of Guangxi Zhuang Autonomous Region Newborn Screening Center were subjected to tandem mass spectrometry (MS/MS) analysis. Newborns with positive results for PCD and their mothers were recalled for retesting. Those who were still positive were subjected to sequencing of the SLC22A5 gene. RESULTS: Twenty-two newborns and 9 mothers were diagnosed with PCD, which gave a prevalence rate of 1/18 208. Sequencing of 18 newborns and 4 mothers have identified 14 types of SLC22A5 gene variants, with the common ones including c.51C>G (10/44, 22.7%), c.1195C>T (9/44, 20.5%) and c.1400C>G (7/44, 15.9%), The c.517delC(p.L173Cfs*3) and c.1031C>T(p.T344I) were unreported previously and predicted to be pathogenic (PVS1+PM2_supporting+PM3+PP4) and likely pathogenic (PM1+PM2_supporting+PM3+PP3+PP4) based on the American College of Medical Genetics and Genomics standards and guidelines. CONCLUSION: c.51C>G, c.1195C>T and c.1400C>G are the most common variants underlying PCD in Guangxi.
Assuntos
Metaboloma , Espectrometria de Massas em Tandem , Cardiomiopatias , Carnitina/deficiência , China , Humanos , Hiperamonemia , Recém-Nascido , Doenças Musculares , Mutação , Membro 5 da Família 22 de Carreadores de Soluto/genéticaRESUMO
OBJECTIVE: To explore the genetic basis of four children with congenital hyperinsulinemia (CHI). METHODS: The four children were subjected to high-throughput whole exome sequencing (WES). Candidate variants were validated by Sanger sequencing. RESULTS: WES analysis has identified 4 variants in the ABCC8 gene and 1 variant in GLUD1, including a ABCC8 c.382G>A variant in case 1, compound heterozygous c.698T>C and c.4213G>A variants of the ABCC8 gene concomitant with a de novo 14.9 Mb microduplication of chromosome 15 in case 2, and ABCC8 c.331G>A variant in case 3, and de novo c.955T>C variant of the GLUD1 gene in case 4. Of these, c.698T>C of the ABCC8 gene and c.955T>C of the GLUD1 gene were unreported previously. Based on the American College of Medical Genetics and Genomics guidelines, the c.382G>A(p.Glu128Lys), c.698T>C(p.Met233Thr) and c.4213G>A(p.Asp1405Asn) variants of ABCC8 gene and c.955T>C(p.Tyr319His) variant of GLUD1 gene were predicted to be likely pathogenic(PM1+PM2+PP3+PP4, PM1+PM2+PM5+PP3+PP4, PM1+PM2+PP3+PP4 and PS1+PM1+PM2+PP3), and the c.331G>A (p.Gly111Arg) variant of ABCC8 gene was predicted to be uncertain significance(PM1+PM2+PP4). CONCLUSION: The variants of the ABCC8 and GLUD1 genes probably underlay the pathogenesis of CHI in the four patients. Above results have facilitated clinical diagnosis and genetic counseling for the affected families.
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Genômica , Hiperinsulinismo , Criança , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Mutação , Sequenciamento do ExomaRESUMO
BACKGROUND: Propionic acidemia (PA) is an autosomal recessive metabolic disorder caused by the deficiency of the mitochondrial protein propionyl-CoA carboxylase (PCC) and is associated with pathogenic variants in either of the two genes PCCA or PCCB. The present study aimed to identify the genetic cause of three Chinese patients with PA. CASE PRESENTATION: Three Chinese PA patients were diagnosed by using gas chromatography-mass spectrometry(GC-MS), tandem mass spectrometry (MS/MS) and molecular diagnostic methods. All patients had onset in the neonatal period. One patient died of infection and metabolic decompensation, and the other two had mild to moderate developmental delay/mental retardation. Mutation analysis of the PCCA gene identified that patient 1 carried the compound heterozygous c.1288C > T(p.R430X) and c.2002G > A(p.G668R), and patient 2 was homozygous for the c.1426C > T(p.R476X) mutation. Mutation analysis of the PCCB gene identified that patient 3 harbored the compound heterozygous mutations c.359_360del AT(p.Y120Cfs*40) and c.1398 + 1G > A. Among these mutations, three (c.1288C > T, c.359_360del AT and c.1398 + 1G > A) are novel. CONCLUSIONS: We reported three Chinese PA patients who had PCCA or PCCB mutants. Among them, in the PCCA gene, c.1288C > T(p.R430X) was a nonsense mutation, resulting in a truncated protein. c.359_360del AT was a frameshift mutation, leading to a p.Y120Cfs*40 change in the amino acid sequence in the PCCB protein. c.1398 + 1G > A was a splicing mutation, causing skipping of the exons 13-14. In conclusion, the novel mutations uncovered in this study will expands the mutation spectrum of PA.
Assuntos
Carbono-Carbono Ligases/genética , Metilmalonil-CoA Descarboxilase/genética , Mutação , Acidemia Propiônica/genética , Pré-Escolar , China , Códon sem Sentido , Análise Mutacional de DNA/métodos , Feminino , Mutação da Fase de Leitura , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Lactente , Recém-Nascido , Masculino , Polimorfismo Genético , Deleção de SequênciaRESUMO
To increase the degree of immobilization of heavy metals subjected to sludge pyrolysis, we investigated the effects of pretreating sludge with Ochrobactrum supplementation on the immobilization of chromium (Cr) and copper (Cu) during sludge pyrolysis. The sequential extraction procedure was used to test the metallic forms of Cr and Cu. The immobilization of Cr and Cu was characterized with X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, etc. Results show that: 1) the addition of Ochrobactrum (1-8%) can accelerate the mineralization process in blank sludge and can accelerate the conversion of the oxidizable forms of Cr and Cu into the residual forms subjected to pyrolysis; 2) pretreatment with Ochrobactrum supplementation can inhibit the volatilization of Cr and Cu during sludge pyrolysis, particularly in the case of a high concentration of Cu. Notably, the pretreatment with Ochrobactrum can reduce 20.38-85.09% of the potential ecological risk of Cr and Cu. The pretreatment with Ochrobactrum contributes to the immobilization of Cr and Cu subjected to sludge pyrolysis and thus can prevent pollution of the environment. The results of this study can be used for harmless disposal of municipal sludge.
Assuntos
Cromo/análise , Cobre/análise , Ochrobactrum/química , Pirólise , Esgotos , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Adsorção , China , Microscopia Eletrônica de Varredura , Ochrobactrum/metabolismo , Oxirredução , Esgotos/química , Esgotos/microbiologiaRESUMO
OBJECTIVE: To explore the value of single nucleotide polymorphism array (SNP-array) for the analysis of pediatric patients with growth retardation. METHODS: One hundred eighty one children with growth retardation were enrolled. DNA was extracted from peripheral samples from the patients, and whole genome copy number variations (CNVs) were detected using Illumina Human Cyto SNP-12. All identified CNVs were further analyzed with reference to databases including ClinGen, ClinVar, DECIPHER, OMIM and DGV as well as comprehensive review of literature from PubMed to determine their pathogenicity. RESULTS: Forty seven patients (26%) with abnormal CNVs were detected, which included 12 known microdeletions/microduplications syndrome (26%), 10 pathogenic non-syndromic CNVs (21%), 3 numerical chromosome aberrations (6%), 3 unbalanced translocations (6%), 4 pathogenic mosaicisms (9%) and 15 cases with unknown clinical significance (32%). After excluding obvious numerical and/or structural chromosomal abnormalities, this study has detected 15 pathogenic microdeletions/microduplications sized 5 Mb or less, which may be missed by routine chromosomal karyotyping. In addition, there were 3 cases with loss of heterozygoisty (LOH) containing known or predicted imprinting genes as well as 2 cases with suspected parental consanguinity. CONCLUSION: SNP-array technology is a powerful tool for the genetic diagnosis of children with growth disorders with advantages of high resolution and improved accuracy.
Assuntos
Deficiências do Desenvolvimento/diagnóstico , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Polimorfismo de Nucleotídeo Único , Adolescente , Criança , Pré-Escolar , Aberrações Cromossômicas , Variações do Número de Cópias de DNA , Deficiências do Desenvolvimento/genética , Feminino , Humanos , Lactente , Cariotipagem , MasculinoRESUMO
OBJECTIVE: To explore the molecular etiology for a Chinese family affected with isolated methylmalonic acidemia (MMA). METHODS: Potential mutations of MUT, MMAA and MMAB genes in the proband were screened by PCR and Sanger sequencing. The pathogenicity of identified mutations was analyzed using Polyphen2, SIFT, HSF, DNAMAN 6.0 and Swiss-PdbViewer4.1.0 software. RESULTS: Two novel mutations of the MUT gene, including c.581C>T (p.P194L) and c.1219A>T (p.N407Y), were discovered in the proband, which were inherited respectively from his mother and father. Bioinformatics analysis suggested that both mutations were damaging. The affected codons P194 and N407, both located in the (beta, alpha) 8 barrel domain and to which the substrate methylmalonyl-CoA is bound, are highly conserved across various species. Both mutations can disrupt the space conformation of its protein product, affecting the function of the MCM protein. CONCLUSION: The novel mutations of MUT gene probably underlie the isolated MMA in this family.
Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/enzimologia , Metilmalonil-CoA Mutase/genética , Mutação Puntual , Adulto , Erros Inatos do Metabolismo dos Aminoácidos/genética , Sequência de Aminoácidos , Animais , Povo Asiático/genética , Sequência de Bases , China , Feminino , Humanos , Lactente , Masculino , Dados de Sequência Molecular , Mutação , Mutação de Sentido Incorreto , Linhagem , Alinhamento de SequênciaRESUMO
OBJECTIVE: To explore the molecular mechanism for a boy suspected with 3-methylcrotonyl-CoA carboxylase deficiency by neonatal screening. METHODS: PCR and Sanger sequencing were used to identify potential mutations of MCCC1 and MCCC2 genes. SIFT and Polyphen-2 software was used to predict the effect of variant on the protein function and conservation of the variant across various species. Human Splicing Finder and Swiss-PdbViewer4.1.0 were applied to analyze the possible mechanism of the variant. RESULTS: For the proband, a compound heterozygous mutation was discovered in the MCCC1 gene, namely c.539G>T (p.G180V) and c.704_711del (p.A235Vfs*4), which were inherited from his father and mother, respectively. The two mutations have disrupted the protein conformation, which in turn may impact the function of MCC protein. CONCLUSION: The compound heterozygous mutations of the MCCC1 gene may contribute to the 3-methylcrotonyl-CoA carboxylase deficiency manifested by the patient.
Assuntos
Carbono-Carbono Ligases/deficiência , Carbono-Carbono Ligases/genética , Mutação , Distúrbios Congênitos do Ciclo da Ureia/genética , Sequência de Aminoácidos , Sequência de Bases , Carbono-Carbono Ligases/química , Análise Mutacional de DNA , Heterozigoto , Humanos , Recém-Nascido , Masculino , Modelos Moleculares , Triagem Neonatal/métodos , Conformação Proteica , Homologia de Sequência de Aminoácidos , Distúrbios Congênitos do Ciclo da Ureia/diagnósticoRESUMO
BACKGROUND: Waardenburg syndrome type I (WS1), an auditory-pigmentary genetic disorder, is caused by heterozygous loss-of-function mutations in PAX3. Abnormal physical signs such as dystopia canthorum, patchy hypopigmentation and sensorineural hearing loss are common, but short stature is not associated with WS1. CASE PRESENTATION: We reported a 4-year and 6 month-old boy with a rare combination of WS1 and severe short stature (83.5 cm (-5.8SD)). His facial features include dystopia canthorum, mild synophrys, slightly up-slanted palpebral fissure, posteriorly rotated ears, alae nasi hypoplasia and micrognathia. No heterochromia was noticed. He had a normal intelligence quotient and hearing. Insulin-like growth factor-1 (IGF-1) was 52.7 ng/ml, lower than the normal range (55 ~ 452 ng/ml) and the peak growth hormone level was 7.57 ng/ml at 90 minutes after taking moderate levodopa and pyridostigmine bromide. The patient exhibited a good response to human growth hormone (rhGH) replacement therapy, showing a 9.2 cm/year growth rate and an improvement of 1 standard deviation (SD) of height after one year treatment. CMA test of patient's DNA revealed a 4.46 Mb de novo deletion at 2q35-q36.2 (hg19; chr2:221,234,146-225,697,363). CONCLUSIONS: PAX3 haploinsufficiency is known to cause Waardenburg syndrome. Examining overlapping deletions in patients led to the conclusion that EPHA4 is a novel short stature gene. The finding is supported by the splotch-retarded and epha4 knockout mouse models which both showed growth retardation. We believe this rare condition is caused by the haploinsufficiency of both PAX3 and EPH4 genes. We further reported a growth response to recombinant human growth hormone treatment in this patient.
Assuntos
Estatura/genética , Deleção Cromossômica , Cromossomos Humanos Par 2/genética , Haploinsuficiência , Receptor EphA4/genética , Síndrome de Waardenburg/genética , Síndrome de Waardenburg/fisiopatologia , Animais , Estatura/efeitos dos fármacos , Criança , Pré-Escolar , Hormônio do Crescimento Humano/farmacologia , Hormônio do Crescimento Humano/uso terapêutico , Humanos , Masculino , Camundongos , Síndrome de Waardenburg/tratamento farmacológicoRESUMO
OBJECTIVE: To investigate the prevalence of hypertension and the relationship between hypertension and obesity in children and adolescents aged 6-18 years in Nanning, Guangxi Province, China. METHODS: A stratified cluster random sampling method was adopted in Nanning to select 7 893 children and adolescents aged 6-18 years as research subjects. Questionnaire surveys were conducted, and blood pressure, height, weight, and other indicators of growth and development were measured. RESULTS: An increasing trend with age for both systolic blood pressure (SBP) and diastolic blood pressure (DBP) was observed. Detection rates of hypertension, high SBP (HSBP) and high DBP (HDBP) were 6.58%, 4.02% and 3.81%, respectively. The detection rates of hypertension and HSBP in boys were significantly higher than in girls (P<0.05). The detection rates of hypertension in normal, overweight and obesity groups were 3.87%, 9.84% and 19.23%, respectively. The obesity group showed the highest detection rates for hypertension, HSBP and HDBP, followed by the overweight group and normal group. Compared with that in the normal group, the odds ratios (95% CI) for hypertension in the overweight and obesity groups were 2.71 (1.69-5.96) and 5.91 (3.46-7.63), respectively. Blood pressure showed a positive correlation with age, height, weight and BMI (P<0.01). CONCLUSIONS: The present study provides with the current information and characteristics of blood pressure of children and adolescents aged 6-18 years in Nanning, Guangxi. Blood pressure is correlated with gender, age, height, weight and BMI. Obesity is positively correlated with the prevalence of hypertension and the risk of hypertension increases with body weight.
Assuntos
Hipertensão/epidemiologia , Obesidade/epidemiologia , Adolescente , Peso Corporal , Criança , China/epidemiologia , Humanos , Prevalência , Caracteres SexuaisRESUMO
More than 90% suspected muscular dystrophy (MD) can be confirmed with multiplex ligation-dependent probe amplification (MLPA) combined with targeted panel, although there are a few that cannot be identified. A total of 312 suspected MD patients were enrolled into the study. The MLPA combined with a targeted myopathy panel were performed. Patients with negative results were subjected to whole exome sequencing (WES), whole genome sequencing (WGS), and/or RNA sequencing (RNA-seq). A total of 275 cases were diagnosed as Duchenne/Becker muscular dystrophy (DMD/BMD) and 20 cases were other types of myopathy or nonmuscular diseases. Six female DMD/BMD patients suffered from varying degrees of typical DMD-like symptoms and 2 others were suspected to be gonadal mosaicism. The systematic application of WES, WGS, and/or RNA-seq highlighted the need for the detection of variants missed by the current standard diagnostic procedures. The identification of female patients and mosaic carriers was crucial to predict the risk of recurrence and allow for optimal genetic counseling.
RESUMO
NSUN2-intellectual disability syndrome, also known as intellectual disability type 5 (MRT5), is an autosomal recessive disorder that is characterized by intellectual disability (ID), postnatal growth retardation, dysmorphic facies, microcephaly, short stature, developmental delay, language impairment and other congenital abnormalities. The disease is caused by mutations in the NSUN2 gene, which encodes a tRNA cytosine methyltransferase that has an important role in spindle assembly during mitosis and chromosome segregation. In this study, we recruited a family that had two individuals with ID. Whole exome sequencing was performed to identify a homozygous frameshift variant (c.1171_1175delACCAT(p.Thr391fs*18*)) in NSUN2 (NM_017755.5) in the proband. The varint was confirmed as segregating in his affected brother and his parents by Sanger sequencing. The individuals that we described showed a similar dysmorphology profile to that associated with MRT5. To analyze the correlations between genotypes of NSUN2 and phenotypes of individuals with ID, we examined 17 variants and the associated phenotypes from 32 ID individuals in current and previous studies. We concluded that mutations in NSUN2 cause a wide range of phenotypic defects. Although some clinical manifestations were highly variable, the core phenotypes associated with NSUN2 mutations were dysmorphic facies, microcephaly, short stature, ID, growth restriction, language impairment, hypotonia and delayed puberty. Our study expands the genetic spectrum of NSUN2 mutations and helps to further define the genotype-phenotype correlations in MRT5.
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Nanismo , Deficiência Intelectual , Transtornos do Desenvolvimento da Linguagem , Microcefalia , Malformações do Sistema Nervoso , Masculino , Humanos , Deficiência Intelectual/genética , Microcefalia/genética , Fácies , Mutação , Fenótipo , China , Linhagem , Metiltransferases/genéticaRESUMO
The WDR19 gene has been reported to be involved in nephronophthisis-related ciliopathies such as isolated nephronophthisis 13 (NPHP13), Sensenbrenner syndrome, Jeune syndrome, Senior-Loken syndrome, Caroli disease, retinitis pigmentosa and Asthenoteratospermia. In the present study, we provided the detailed clinical characteristics and genetic analysis of a patient with four variants in WDR19 and TG, reviewed a comprehensive mutation analysis in the WDR19-related ciliopathies, discussed the relationship between genotype and phenotype, and compared the allele frequencies (AFs) of WDR19 variants depending on the ethnic background. We used whole-exome sequencing (WES) combined with bioinformatics analysis to investigate the genetic variants of a 3-year-old boy with common features of WDR19-associated NPHP13 and Caroli disease, bilateral central blindness, refractory epilepsy, and elevated thyroid stimulating hormone. A novel splice-donor variant, c.98+1G > C, and a recurrent missense variant, c.3533G > A, were identified in the WDR19 gene. We used effective mRNA analysis to verify the effects on pre-mRNA processing and to assess the pathogenicity of the splice-site variant. The patient also harbored compound heterozygous variants of the TG gene (c.4889A > G, c.274+2T > G). Of note, using a review of an in-house database, we identified four additional likely pathogenic WDR19 variants and estimated the overall AF of WDR19 mutations to be 0.0025 in the southern Chinese population. Our findings have expanded the allelic spectrum of mutations in the WDR19 gene and broadened the clinical phenotype spectrum of WDR19-related ciliopathies. The results have also provided new insights into the clinical heterogeneity of the disorder, which would be useful in accurate genetic counseling for affected individuals and carrier screening in a general population.
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OBJECTIVE: ALS2-related disorder involves retrograde degeneration of the upper motor neurons of the pyramidal tracts, among which autosomal recessive Infantile-onset ascending hereditary spastic paralysis (IAHSP) is a rare phenotype. In this study, we gathered clinical data from two Chinese siblings who were affected by IAHSP. Our aim was to assess the potential pathogenicity of the identified variants and analyze their clinical and genetic characteristics. METHOD: Here, Whole-exome sequencing (WES) was performed on proband to identify the candidate variants. Subsequently, Sanger sequencing was used to verify identified candidate variants and to assess co-segregation among available family members. Utilizing both silico prediction and 3D protein modeling, an analysis was conducted to evaluate the potential functional implications of the variants on the encoded protein, and minigene assays were performed to unravel the effect of the variants on the cleavage of pre-mRNA. RESULTS: Both patients were characterized by slurred speech, astasia, inability to walk, scoliosis, lower limb hypertonia, ankle clonus, contracture of joint, foot pronation and no psychomotor retardation was found. Genetic analysis revealed a novel homozygous variant of ALS2, c.1815G > T(p.Lys605Asn) in two Chinese siblings. To our knowledge, it is the first confirmed case of a likely pathogenic variant leading to IAHSP in a Chinese patient. CONCLUSION: This study broadens the range of ALS2 variants and has practical implications for prenatal and postnatal screening of IAHSR. Symptom-based diagnosis of IAHSP is frequently difficult for medical practitioners. WES can be a beneficial resource to identify a particular disorder when the diagnosis cannot be determined from the symptoms alone.
Assuntos
Esclerose Lateral Amiotrófica , Fatores de Troca do Nucleotídeo Guanina , Irmãos , Paraplegia Espástica Hereditária , Feminino , Gravidez , Humanos , Mutação , Fatores de Troca do Nucleotídeo Guanina/genética , Análise Mutacional de DNA , Biologia Molecular , China , LinhagemRESUMO
Trichohepatoneurodevelopmental syndrome is an extremely uncommon autosomal recessive disorder resulting from variants in the CCDC47 gene, which encodes a Ca2+-binding endoplasmic reticulum (ER) transmembrane protein. To date, only four patients with CCDC47 deficiency have been reported, all of them with homozygous truncating CCDC47 variants. For this study, a Chinese family was recruited, which included a patient diagnosed with trichohepatoneurodevelopmental syndrome. Whole exome sequencing (WES) identified the proband's novel homozygous CCDC47 variation (NM_020198: c.634C > T(p.Arg212*). The variant was confirmed to be segregating in the proband and her unaffected relatives through Sanger sequencing. The patient described exhibited a clinical phenotype similar to that of patients with the CCDC47 variant. Compared to reported cases with CCDC47 pathogenic variants, our patients showed a novel complication of hearing impairment. In addition, brain abnormalities, small feet, bilateral hip dislocation, hip dysplasia, overlapping toes, pectus excavatum, scoliosis and narrow chest were not observed in our patient. We also examined five different variations and their corresponding phenotypes from five patients, both in current and previous research. Although some clinical manifestations of trichohepatoneurodevelopmental syndrome were highly variable, the most common phenotypes observed in these patients include microcephaly, profound intellectual disability, severe global development delay, pronounced growth restriction, hypotonia, woolly hair, facial dysmorphism, respiratory and visual abnormalities, gastrointestinal abnormalities, liver dysfunction, pruritus, skeletal and limb abnormalities, congenital heart defects and immunodeficiency. The present report is the first of a Chinese infant with homozygous variant in the CCDC47 gene. We expanded the genetic and phenotypic spectrum associated with trichohepatoneurodevelopmental syndrome.