Genetic research progress in branchio-oto syndrome/ branchio-oto-renal syndrome / 中南大学学报(医学版)

Branchio-oto syndrome (BOS)/branchio-oto-renal syndrome (BORS) is a kind of autosomal dominant heterogeneous disorder. These diseases are mainly characterized by hearing impairment and abnormal phenotype of ears, accompanied by renal malformation and branchial cleft anomalies including cyst or fistula, with an incidence of 1/40 000 in human population. Otic anormalies are one of the most obvious clinical manifestations of BOS/BORS, including deformities of external, middle, inner ears and hearing loss with conductive, sensorineural or mix, ranging from mild to profound loss. Temporal bone imaging could assist in the diagnosis of middle ear and inner ear malformations for clinicians. Multiple methods including direct sequencing combined with next generation sequencing (NGS), multiplex ligation-dependent probe amplification (MLPA), or array-based comparative genomic hybridization (aCGH) can effectively screen and identify pathogenic genes and/or variation types of BOS/BORS. About 40% of patients with BOS/BORS carry aberrations of EYA1 gene which is the most important cause of BOS/BORS. A total of 240 kinds of pathogenic variations of EYA1 have been reported in different populations so far, including frameshift, nonsense, missense, aberrant splicing, deletion and complex rearrangements. Human Endogenous Retroviral sequences (HERVs) may play an important role in mediating EYA1 chromosomal fragment deletion mutations caused by non-allelic homologous recombination. EYA1 encodes a phosphatase-transactivator cooperated with transcription factors of SIX1, participates in cranial sensory neurogenesis and development of branchial arch-derived organs, then regulates the morphological and functional differentiation of the outer ear, middle ear and inner ear toward normal tissues. In addition, pathogenic mutations of SIX1 and SIX5 genes can also cause BOS/BORS. Variations of these genes mentioned above may cause disease by destroying the bindings between SIX1-EYA1, SIX5-EYA1 or SIX1-DNA. However, the role of SIX5 gene in the pathogenesis of BORS needs further verification.

Genetic analysis of a case with mosaicism of a small supernumerary marker chromosome derived from idic(15) / 中华医学遗传学杂志

OBJECTIVE@#To determine the origin of a mosaicism small supernumerary marker chromosome (sSMC) by cytogenetic and molecular analysis.@*METHODS@#Karyotype analysis, fluorescence in situ hybridization (FISH) and SNP-array were carried out.@*RESULTS@#The karyotype of the patient was mos47,XX,+mar[45]/48,XX,+2mar[3]/46,XX[52]; the SNP-array result was arr[hg19]15q11.1q11.2 (20 161 372-24 314 675)×3, and the repeat fragment was about 4.15 Mb. FISH showed that approximately 50% of the cells have contained a sSMC with double D15Z1 probe site segments derived from abnormal idic(15). This sSMC did not contain SNRPN and PML probe fragments of Prader-Willi syndrome/Angelman syndrome.@*CONCLUSION@#When the patient's karyotype and phenotype are inconsistent, cytogenetic and molecular biology technologies should be combined to clarify the karyotype and gene location, so as to provide more accurate genetic consultation for the follow-up treatments.

Genetic analysis of a fetus with mosaicism of 13q inversion duplication / 中华医学遗传学杂志

OBJECTIVE@#To report on a case of mosaicism 13q inversion duplication, analyze its mechanism, and discuss the correlation between its genotype and phenotype.@*METHODS@#Amniotic fluid and umbilical cord blood were collected at 23 and 32 weeks of gestation, respectively. Combined with G-banding chromosome karyotyping analysis, single nucleotide polymorphism array (SNP-array) and fluorescence in situ hybridization (FISH) were used to confirm the result.@*RESULTS@#The karyotype of the fetus was determined as 47,XY,+inv dup(13)(q14.3q34)/46,XY. After careful counseling, the couple decided to continue with the pregnancy, and had given birth to a boy at 40 weeks' gestation. Except for a red plaque (hemangioma) on the nose bridge, no obvious abnormality (intelligence to be evaluated) was discovered.@*CONCLUSION@#To provide reference for clinical genetic counseling and risk assessment, the location and proportion of new centromere formation should be fully considered in the case of mosaicism 13q inversion duplication.

5p13. 2 Chromosomal duplication syndrome: case report and literature review / Síndrome de duplicação cromossômica 5p13. 2: relato de caso e revisão da literatura

Chromosome 5p13 duplication syndrome represents a contiguous gene syndrome involving duplication of several genes on chromosome 5p13. Some clinical phenotypes are related to it, such as: obsessive-compulsive behavior, small palpebral fissures, intellectual disability, global development delay and ocular hypertelorism. The exact mechanism behind these changes has not well known and further studies are needed for this purpose. Since it is a rare and uncommon clinical situation, the case report contributes to the knowledge of the disease and early diagnosis. This condition mainly affects the cognitive neuromuscular system. We describe an 8-year-old Brazilian patient with the duplication of chromosome 5p13.2, karyotype, whose neurodevelopmental evaluation presented cognitive impairment, severe language delay and atypical physical examination, with ocular hypertelorism, right auricular tags, congenital heart defect and long fingers. The patient was diagnosed by comparative genomic hybridization (CGH)-array revealing a 204Kb of DNA duplication. The exact mechanism behind these structural disorders is still unclear and further studies are needed for this purpose. Nevertheless, the diagnostic suspicion of this genetic alteration that, in general, presents late diagnosis, should be considered to enable better clinical support to the patients and family genetic counseling.

A síndrome da duplicação do cromossomo 5p13 representa uma síndrome genética contígua envolvendo a duplicação de vários genes contidos nesta região. Alguns fenótipos clínicos estão relacionados com ela, tais como: comportamento obsessivo compulsivo, fissuras palpebrais pequenas, déficit intelectual, atraso no desenvolvimento global e hipertelorismo ocular. Por ser uma situação clínica rara, o relato do caso contribui para a disseminação do conhecimento acerca da condição, assim como para seu diagnóstico precoce. Descrevemos uma paciente brasileira de oito anos com a duplicação do cromossomo 5p13.2, que na avaliação do neurodesenvolvimento apresentou comprometimento cognitivo, grave atraso da linguagem e dismorfismos como hipertelorismo ocular, apêndice auricular direito, sopro cardíaco, relacionado a defeito do septo ventricular, e dedos alongados. A paciente foi diagnosticada por meio da pesquisa molecular (CGH)-array com ganho de 204Kb de DNA. O mecanismo exato por trás dessas alterações estruturais ainda não está claro e são necessários mais estudos para este fim. Não obstante, a suspeita diagnóstica dessa alteração genética que, em geral, apresenta diagnóstico tardio, deve ser aventada para viabilizar melhor suporte clínico aos pacientes e aconselhamento genético familiar.

Advances in identification methods of alien genomic components in plants / 生物工程学报

Plants with alien genomic components (alien chromosomes / chromosomal fragments / genes) are important materials for genomic research and crop improvement. To date, four strategies based on trait observation, chromosome analysis, specific proteins, and DNA sequences have been developed for the identification of alien genomic components. Among them, DNA sequence-based molecular markers are mainly used to identify alien genomic components. This review summarized several molecular markers for identification of alien genomic components in wheat, cabbage and other important crops. We also compared the characteristics of nine common molecular markers, such as simple sequence repeat (SSR), insertion-deletion (InDel) and single nucleotide polymorphism (SNP). In general, the accuracy of using a combination of different identification methods is higher than using a single identification method. We analyzed the application of different combination of identification methods, and provided the best combination for wheat, brassica and other crops. High-throughput detection can be easily achieved by using the new generation molecular markers such as InDel and SNP, which can be used to determine the precise localization of alien introgression genes. To increase the identification efficiency, other new identification methods, such as microarray comparative genomic hybridization (array-CGH) and suppression subtractive hybridization (SSH), may also be included.

Genetic analysis of a case with Pierre-Robin sequence due to partial 1q trisomy and partial 4q monosomy / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a neonate with Pierre-Robin sequence.@*METHODS@#The child was subjected to chromosomal karyotyping, single nucleotide polymorphism array (SNP-array)-based comparative genomic hybridization and fluorescence in situ hybridization (FISH) analysis.@*RESULTS@#The child has featured microgthnia, glossoptosis, upper airway obstruction, mandible dehiscence and short neck. He was found to have a karyotype of 46,XY,der(4)add(4)(q34). Her mother's karyotype was determined as 46,XX,t(1;4)(q43;q34), while his father was 46,XY. SNP-array analysis suggested the child to be arr [hg19] 1q42.2q44 (232 527 958-249 202 755)× 3; 4q34.3q35.2 (168 236 901-190 880 409)× 1. The result of SNP-array for both parents was normal. FISH analysis confirmed that his mother has carried a balanced t(1;4)(q42;34) translocation. The aberrant chromosome 4 in the child has derived from his mother's translocation, which gave rise to partial 1q trisomy and 4q monosomy.@*CONCLUSION@#The 1q42.2q44 duplication and 4q34.3q35.2 deletion of the child probably underlay his abnormal phenotype of Pierre-Robin sequence.

Estudios genéticos y neurodesarrollo: De la utilidad al modelo genético / Genetic studies and neurodevelopment. From effectiveness to genetic models]

Los avances en la genética han podido apoyar la sospecha que aportaba la experiencia clínica sobre el gran componente hereditario de la mayor parte de estos trastornos del neurodesarrollo (TND). Los estudios iniciales de heredabilidad, ligamiento o asociación evidenciaron desde los inicios la gran contribución de la variación genotípica a la clínica en general, y a los TND en particular. No debe obviarse la utilidad de los estudios genéticos en el ejercicio clínico, encaminados al diagnóstico etiológico. La mayor parte de los mismos están protocolizados en el estudio de trastornos como la discapacidad intelectual y el autismo; dentro de éstos, la hibridación por arrays cromosómicos ha aportado una mayor rentabilidad diagnóstica respecto a técnicas citogenéticas históricas (3 vs. 10% respectivamente). Sin embargo, la irrupción y rentabilidad de técnicas de genética molecular por secuenciación, particularmente la exómica y genómica en trío, analizando a padres, (tasas diagnósticas del 30-50%), están condicionando la modificación de los algoritmos genéticos en el diagnóstico de trastornos graves del neurodesarrollo. El mayor conocimiento de variantes causales de discapacidad intelectual y autismo está igualmente modificando los modelos teóricos poligénicos establecidos hasta la fecha.

Advances in genetics have been able to support the clinical suspicion on the large hereditary component of most of these neurodevelopmental disorders (NDD). Initial studies on heritability, linkage or association showed from the beginning the great contribution of genotypic variation to the clinic in general, and to NDD in particular. The effectiveness of genetic studies in clinical practice, targeted to aetiological diagnosis, should not be ignored. Most of these are protocolized in the study of disorders such as intellectual disability and autism; within these, the array comparative genomic hybridization have supported a greater diagnostic effectiveness with respect to historical cytogenetic techniques (3 vs. 10% respectively). However, the irruption and success of molecular genetic sequencing techniques, particularly the exome and genome in trio, analyzing the parents (diagnostic rates of 30-50%), are conditioning the modification of the genetic algorithms in the diagnosis of different NDD. The greater knowledge of causal variants in intellectual disability and autism is also modifying the polygenic theoretical models established to date.

Identification of LINS1 gene variant in a patient with severe mental retardation / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis of a child with idiopathic mental retardation.@*METHODS@#Clinical data and peripheral blood sample of the child were collected. Genomic DNA was extracted and subjected to copy number analysis using single nucleotide polymrophism array comparative genome hybridization (SNP-aCGH) and targeted capture and next generation sequencing (NGS).@*RESULTS@#No microdeletion/microduplication were detected by SNP-aCGH. NGS has detected homozygous c.722delA (p.Asp241fs) variant of the LISN1 gene, which is known to underlie autosomal recessive mental retardation-27 (MRT 27). Both parents are carriers of the variant, conforming to the autosomal recessive inheritance.@*CONCLUSION@#A novel pathogenic variant of the LINS1 gene has been identified, which probably underlies the MRT 27 in the patient.

Genetic analysis of a child with atypical Williams-Beuren syndrome presenting as supravalvular aortic stenosis / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child with supravalvular aortic stenosis.@*METHODS@#The child and his parents were subjected to conventional G-banding karyotyping, array comparative genomic hybridization (aCGH) and multiplex ligation-dependent probe amplification (MLPA) analysis.@*RESULTS@#No karyotypic abnormality was detected in the child and his parents. aCGH has identified a de novo 278 kb deletion encompassing the ELN gene in 7q11.23, which overlapped with the critical region of Williams-Beuren syndrome (WBS). MLPA has confirmed above findings.@*CONCLUSION@#The proband was diagnosed with atypical WBS. Deletion of the ELN gene may predispose to supravalvular aortic stenosis in the proband.

Advance in research on microdeletion/microduplications at Xp22.3 / 中华医学遗传学杂志

With the application of BACs-on-Beads (BoBs) and array-comparative genome hybridization (aCGH) technologies in prenatal diagnosis, microdeletion/microduplications at Xp22.3 have been frequently detected. However, the relatively high prevalence and lack of knowledge of such disorders have brought difficulties for clinical genetic counseling. Here, recent progress of research on microdeletion/microduplications at Xp22.3, including epidemiology, pathogenesis, clinical manifestation, and prenatal diagnosis, is reviewed.

Identification of ATP7B gene variant by combined use of Sanger sequencing, array CGH and quantitative PCR / 中华医学遗传学杂志

OBJECTIVE@#To identify the type and origin of ATP7B gene mutation in a family affected with Wilson disease by combined use of multiple methods.@*METHODS@#Peripheral blood samples were collected from the proband, her parents and her brother. Sanger sequencing were used to detect point mutation and small deletion/insertion of the 21 exons and flanking sequences of the ATP7B gene in all family members. Array-based comparative genomic hybridization (aCGH) was performed to identify copy number variations (CNVs) of the ATP7B gene in the proband. The result was validated by quantitative PCR (qPCR) in other 3 members.@*RESULTS@#Sanger sequencing indicated that the proband carried a heterozygous variation c.2668G>A (p.V890M) derived from her mother. In addition, 5 common SNPs were detected in her mother, three of which were also identified in her father and brother. The 5 SNPs in the proband were of the wide type. aCGH analysis demonstrated that the proband was heterozygous for a 4 kb deletion, which encompassed exons 2 and 3 of the ATP7B gene and 2 SNPs. qPCR showed that the copy number in her father and brother was about half of the control, indicating heterozygous loss of exons 2 and 3.@*CONCLUSION@#The combined Sanger sequencing, array CGH and qPCR has identified a novel CNV involving the ATP7B gene. The strategy can improve the diagnostic rate for hereditary or rare diseases.

Genetic diagnosis of a child with Smith-Magenis syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the molecular mechanism of a girl with developmental delay and intellectual disability.@*METHODS@#Chromosomal karotypes of the child and her parents were analyzed with routine G-banding method. Their genomic DNA was also analyzed with array comparative genomic hybridization (aCGH) for chromosomal duplications/deletions.@*RESULTS@#No karyotypic abnormality was detected in the child and her parents, while aCGH has identified a de novo 3.37 Mb deletion at 17p11.2 in the child.@*CONCLUSION@#The child was diagnosed with Smith-Magenis syndrome, for which RAI1 may be the causative gene.

Prenatal diagnosis of partial trisomy 3q in a fetus / 中华医学遗传学杂志

OBJECTIVE@#To carry out prenatal diagnosis for a fetus with ultrasonographic abnormality.@*METHODS@#Chromosomal karyotyping and array comparative genomic hybridization (array-CGH) analysis were applied for the diagnosis. Peripheral blood samples were also taken from the parents for chromosome karyotyping analysis.@*RESULTS@#The fetal karyotype showed additional material of unknown-origin attached to Yq. Array CGH analysis confirmed that the material was derived from 3q22.1q29. The father was found to carry a balanced translocation 46, X, t(Y;3)(q12;q23) (which was diagnosed as 46,XY,Y≥18 elsewhere), whilst the mother was found to be normal.@*CONCLUSION@#3q partial trisomy may present as malformation of multiple systems. Combination of chromosome karyotyping and array-CGH can provide reliable diagnosis for fetuses with abnormalities by ultrasonography.

Effects of Copy Number Variations on Developmental Aspects of Children With Delayed Development

OBJECTIVE: To determine effects of copy number variations (CNV) on developmental aspects of children suspected of having delayed development. METHODS: A retrospective chart review was done for 65 children who underwent array-comparative genomic hybridization after visiting physical medicine & rehabilitation department of outpatient clinic with delayed development as chief complaints. Children were evaluated with Denver Developmental Screening Test II (DDST-II), Sequenced Language Scale for Infants (SELSI), or Preschool Receptive-Expressive Language Scale (PRES). A Mann-Whitney U test was conducted to determine statistical differences of developmental quotient (DQ), receptive language quotient (RLQ), and expressive language quotient (ELQ) between children with CNV (CNV(+) group, n=16) and children without CNV (CNV(–) group, n=37). RESULTS: Of these subjects, the average age was 35.1 months (mean age, 35.1±24.2 months). Sixteen (30.2%) patients had copy number variations. In the CNV(+) group, 14 children underwent DDST-II. In the CNV(–) group, 29 children underwent DDST-II. Among variables, gross motor scale was significantly (p=0.038) lower in the CNV(+) group compared with the CNV(–) group. In the CNV(+) group, 5 children underwent either SELSI or PRES. In the CNV(–) group, 27 children underwent above language assessment examination. Both RLQ and ELQ were similar between the two groups. CONCLUSION: The gross motor domain in DQ was significantly lower in children with CNV compared to that in children without CNV. This result suggests that additional genetic factors contribute to this variability. Active detection of genomic imbalance could play a vital role when prominent gross motor delay is presented in children with delayed development.

Recurrent Angelman syndrome caused by a rare partial deletion of UBE3A gene / 中华医学遗传学杂志

OBJECTIVE@#To provide genetic testing for two brothers with mental retardation and epilepsy.@*METHODS@#Array comparative genomic hybridization (aCGH) was used to detect copy number variations in the two patients, their parents and maternal grandparents. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) was utilized to delineate the deleted region in the pedigree.@*RESULTS@#A 138 kb deletion in 15q11.2 region was detected by aCGH in both patients, which encompassed part of the UBE3A gene. MS-MLPA has narrowed down the region to exons 8 to 14 of the UBE3A gene. The same deletion was also found in their mother and grandfather.@*CONCLUSION@#The pathogenesis of this rare form of recurrent Angelman syndrome may be attributed to the partial deletion of maternal UBE3A gene.

Advantages of Array Comparative Genomic Hybridization Using Buccal Swab DNA for Detecting Pallister-Killian Syndrome

No abstract available.

Preimplantation genetic diagnosis for infertile males with autosomal dominant polycystic kidney disease / 中华男科学杂志

<p><b>Objective</b>Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common genetic renal diseases, which may cause oligoasthenospermia and azoospermia and result in male infertility. This study aimed to analyze the outcomes of preimplantation genetic diagnosis (PGD) in male patients with ADPKD-induced infertility.</p><p><b>METHODS</b>We retrospectively analyzed the clinical data on 7 male patients with ADPKD-induced infertility undergoing PGD from April 2015 to February 2017, including 6 cases of oligoasthenospermia and 1 case of obstructive azoospermia, all with the PKD1 gene heterozygous mutations. Following intracytoplasmic sperm injection (ICSI), we performed blastomere biopsy after 5 or 6 days of embryo culture and subjected the blastomeres to Sureplex whole-genome amplification, followed by haplotype linkage analysis, Sanger sequencing, array-based comparative genomic hybridization to assess the chromosomal ploidy of the unaffected embryos, and identification of the unaffected euploid embryos for transfer.</p><p><b>RESULTS</b>One PGD cycle was completed for each of the 7 patients. Totally, 26 blastocysts were developed, of which 12 were unaffected and diploid. Clinical pregnancies were achieved in 6 cases following 7 cycles of frozen embryo transplantation, which included 5 live births and 1 spontaneous abortion.</p><p><b>CONCLUSIONS</b>For males with ADPKD-induced infertility, PGD may contribute to high rates of clinical pregnancy and live birth and prevent ADPKD in the offspring as well. This finding is also meaningful for the ADPKD patients with normal fertility.</p>

Clinical and genetic features of ring chromosome 13 syndrome: an analysis of one case / 中国当代儿科杂志

A girl aged 5 months was admitted due to developmental delay. Physical examination showed delayed physical development, unusual facies (microcephalus, hypertelorism, low-set ears, wide nasal bridge, and short philtrum), and an absence of the labium minus at one side. The peripheral blood karyotype was 46,XX,r(13)(p11q33)[82]/45,XX,-13[10]/46,XX,r(13;13)(p11q33;p11q33)[8], and array-based comparative genomic hybridization showed an 87.5 Mb duplication in 13q11q33.2 region and an 8.2 Mb deletion in 13q33.2q34 region. Fluorescence in situ hybridization showed terminal depletion of the long arm of the ring chromosome 13. The girl was diagnosed with ring 13 syndrome. This syndrome has various clinical phenotypes and is closely associated with the amount and site of the loss of genetic material in chromosomal band and different rates of chimerism.

Progress of Clinical Application of SNP-A to MDS--Review / 中国实验血液学杂志

Cytogenetic abnormalities get wide attention for its guidance value for prognosis and therapy in myelodysplastic syndrome (MDS) and related malignancies. Cytogenetic analysis is also the key to clarify the molecular pathogenesis of these kinds of diseases. The traditional karyotyping technique including metaphase cytogenetic (MC) karyotype analysis and immune fluorescence in situ hybridization (FISH) can detect the chromosomal abnormalities to some degree while the positive rate detected by the techniques is low due to the low resolution, dependence on metaphase dividing cells or the limitation of specific sites on the chromosomes, respectively. Although array comparative genomic hybridization (aCGH) makes up for some deficiencies of the techniques above, only copy number variations (CNVs) could be detected by aCGH. Recently, single nucleotide polymorphasim array (SNP-A) are employed to detect chromosomal CNVs and uniparental disomies (UPDs) which are significant for illumination of the pathogenetics and prognosis of MDS. Based on the detection principle and characteristics of SNP-A, this article reviews the clinical application and prospect of the technique in aspect of the detection characteristic of SNP-A, the relationship between cryptic aberrations and MDS related aspects including the pathogenic genes, phenotypes, prognosis, stratification system and self control test.

Prenatal chromosomal microarray analysis of fetus with increased nuchal translucency

Nuchal translucency is an important indicator of an aneuploid fetus in prenatal diagnostics. Previously, only the presence of aneuploid could be confirmed by conventional karyotyping of fetuses with thick nuchal translucency. With the development of genetic diagnostic techniques, however, it has been reported that subtle variations not detectable by conventional karyotyping might occur in cases of pathologic clinical syndrome in euploid fetuses. One of the newer, high-resolution genetic methods in the prenatal setting is chromosomal microarray. The possible association between nuchal translucency thickness with normal karyotype and submicroscopic chromosomal abnormalities detectable by microarray has been studied. How and when to apply microarray in clinical practice, however, is still debated. This article reviews the current studies on the clinical application of microarray in cases of increased nuchal translucency with normal karyotype for prenatal diagnosis.