三例Kleefstra综合征患儿临床和遗传学分析

目的对3例不明原因的发育迟缓(developmental delay, DD)/智力障碍(intellectual disability, ID)患儿进行临床症状和染色体微阵列分析(chromosome microarray analysis, CMA), 明确其可能的病因。方法采集3例DD/ID患儿的外周静脉血样, 进行CMA检测。结果例1的9号染色体q34.3区段约有190 kb的DNA片段缺失, 包含Kleefstra综合征(OMIM 610253)的关键基因EHMT1(OMIM 607001)的大部分区域;例2和例3为同胞姐妹, CMA检测显示均存在相同的4处染色体片段异常, 其中9号染色体q34.3区域缺失长度分别是154 kb和149 kb, 均包含EHMT1和CACNA1B(OMIM 601012)基因, 其余变异无临床意义。结论 3例患儿的染色体9q34.3微缺失可能是其DD/ID的致病原因, EHMT1是关键基因。     

三例Kleefstra综合征患儿的基因变异分析

目的:对3例Kleefstra综合征患儿进行 EHMT1基因变异分析,探讨其可能的致病原因。 方法:采集患儿及其父母的外周血进行全外显子测序(whole exome sequencing,WES),其中基因拷贝数变异(copy number variation, CNV)应用Realtime-PC...     

一例Sifrim-Hitz-Weiss综合征患儿的临床与CHD4基因变异分析

目的探讨一例Sifrim-Hitz-Weiss综合征(Sifrim-Hitz-Weiss syndrome,SIHIWES)患儿的基因型与表型的对应关系。方法收集先证者及其父母的外周血样,提取基因组DNA,采用全外显子测序对先证者进行检测,并应用Sanger测序对先证者及父母进行验证。结果先证者为一例2岁女性患儿,表现为全面发育迟缓、智力障碍、特殊面容等。其产前表现为NT增厚,颅面部异常和胎动减少等。全外显子测序发现患儿CHD4基因发生了致病性变异NM_001273:c.2989C>G(p.Leu997Val)(GRCh37/hg19)。与以往报道的SIHIWES的临床表型相比,该患儿产前临床特征未有描述,而产后某些新的表型包括眼底检查结果和某些特殊面容如左右耳不对称、眼睑下垂、长人中和嘴角下斜等也呈现出来。结论本文研究结果扩展了CHD4基因变异谱,并丰富了SIHIWES的临床表型谱。     

Clinical and genetic features of five patients with Allan-Herndon-Dudley syndromeCSCD

Objective: To delineate the clinical and genetic characteristics of patients with Allan-Herndon-Dudley syndrome (AHDS). Methods: Genetic testing was carried out by next generation sequencing on 117 patients featuring intellectual disability and developmental delay. Clinical information including clinical manifestation, brain magnetic resonance imaging (MRI), thyroid hormone levels, and electrocardiogram was collected for those with SLC16A2 mutations. Results: Five male patients with SLC16A2 gene mutations were identified, including 2 affected brothers and 3 sporadic cases. The ages of the patients ranged from 8 months to 8 years. All patients presented with severe intellectual disability and developmental delay including poor head control, inability to sit independently, no speech, and poor response to external stimuli. All patients presented with hypotonia, dystonia, and positive pyramidal signs. Three patients had sinus tachycardia. All patients had abnormal thyroid hormone levels with elevated free triiodothyronine (FT 3 ), decreased free tetraiodothyronine(FT 4 ), and normal thyroid stimulating hormone (TSH). Brain MRI on 3 patients showed delayed myelination. Among the 3 sporadic patients, 2 carried de novo mutations including c. 61G>T(p. E21X) and c. 695-699delATGGT(p. N232SfsX7), respectively, 1 carried a c. 42delC(p. W15GfsX69) mutation, which was inherited from his heterozygous mother. A nonsense mutation (c. 9160T, p. Q306X) was discovered in the two brothers, for which their mother was heterozygous. Conclusion: AHDS is characterized by severe psychomotor developmental delay as well as congenital hypotonia, dystonia and positive pyramidal signs. Affected males may present with distinctive thyroid hormone abnormalities including increased FT 3 and low FT 4 accompanied by normal TSH. Delayed meylination of white matter is common. It is an X-linked mental retardation caused by SLC16A2 gene mutations. © 2018 MeDitorial Ltd. All rights reserved.     

Genetic analysis of two children patients affected with CHARGE syndromeCSCD

Objective To analyze two Chinese pediatric patients with multiple malformations and growth and development delay. Methods Both patients were subjected to targeted gene sequencing, and the results were analyzed with Ingenuity® Variant Analysis™ software. Suspected pathogenic variations were verified by Sanger sequencing. Results High-throughput sequencing showed that both patients have carried heterozygous variants of theCHD7 gene. Patient 1 carried a nonsense mutation in exon 36 (c. 79570T, p. Arg2653 ∗), while patient 2 carried a nonsense mutation of exon 2 (c. 7180T, p. Gln240 ∗ ). Sanger sequencing confirmed the above mutations in both patients, while their parents were of wild-type for the corresponding sites, indicating that the two mutations have happened de novo. Conclusion Two patients were diagnosed with CHARGE syndrome by high-throughput sequencing. © 2018 West China University of Medical Sciences. All rights reserved.     

Small interstitial 9p24.3 deletions principally involving KANK1 are likely benign copy number variants

A small heterozygous deletion involving KANK1 was originally reported in 2005 to cause cerebral palsy in one large Israeli family of Jewish Moroccan origin. There were nine affected children over two generations to five unaffected fathers. All of these children had congenital hypotonia that evolved into spastic quadriplegia over the first year of life, along with intellectual impairment and brain atrophy. The subsequent clinical depictions of other individuals with neurological disease harbouring a comparable KANK1 deletion have been extremely variable and most often quite dissimilar to the original family. The reported pathogenicity of these deletions has also been variable, due to an inconsistent nature of reported disease associations and limited data. We therefore sought to perform a review of the significance of small distal interstitial chromosome 9p24.3 deletions principally involving KANK1, including data from the VCGS cytogenetics laboratory. We found that carrier parents do not appear to display an increased frequency of neurological disease, individuals with a small KANK1 deletion have sometimes been found to have an alternate genetic diagnosis that explained their neurological condition, and small KANK1 deletions can be seen with approximate equal frequency in case and control populations. These data led us to conclude that small deletions involving KANK1 do not cause a highly-penetrant influence of large effect size and they are unlikely to contribute significantly to the aetiology of disease in patients with development delay, intellectual disability, autism or cerebral palsy. We recommend searching for an alternate explanation for disease in individuals with a neurological disorder found to have a small deletion involving KANK1.     

拷贝数变异分析对于不明原因智力障碍/发育迟缓患儿的诊断价值

目的:评估拷贝数变异(copy number variations,CNVs)分析在智力障碍/发育迟缓(intellectual disability/developmental delay, ID/DD)患者遗传学病因诊断中的价值。方法:对2015年1月至2019年12月本院确诊为ID/DD的530例患儿进行核型分析...     

一例不典型新生儿猫叫综合征的遗传学分析CSCD

目的对1例仅表现为哭声无力,声音嘶哑,无特殊面容,不伴有先天性心脏病等其他症状或体征的不典型新生儿猫叫综合征患儿的临床及遗传学特点进行分析。方法对患儿及其父母外周血淋巴细胞G显带染色体核型分析,对患儿用应荧光原位杂交技术（fluorescence in situ hybridization, FISH）进行验证,之后用染色体微阵列法（chromosome microarray analysis, CMA）进一步精确遗传学分析。结果患儿染色体核型分析结果为46,XX,del（5）（p14p15）,其父母外周血染色体核型分析未见异常。FISH结果证实了此缺失的存在。染色体微阵列检测结果显示患儿chr5p15．33p14．1区域存在25．7Mb片段缺失。结论猫叫综合征患者个体表型可存在较大差异,尤其是对于新生儿易导致漏诊、误诊。应用细胞遗传学与分子遗传学技术相结合的综合分析有利于弥补单一方法的不足,更加精确地对缺失片段进行定位。     

三例额外小标记染色体的细胞及分子遗传学分析

目的:对3例微小额外标记染色体(small supernumerary marker chromosomes,sSMC)的来源与结构进行鉴定,探讨其发生机理,为临床遗传咨询提供参考。方法:应用染色体显带技术(G带、C带、N带)进行染色体核型分析,基因芯片技术明确sSMC片段的来源和区域,并用荧光原位杂交(fluores...     

The role of the gut microbiota in patients with Kleefstra syndrome

Kleefstra Syndrome (KS) is a rare monogenetic syndrome, caused by haploinsufficiency of the euchromatic histone methyl transferase 1 (EHMT1) gene, an important regulator of neurodevelopment. The clinical features of KS include intellectual disability, autistic behavior and gastrointestinal problems. The gut microbiota, an important modifier of the gut-brain-axis, may constitute an unexplored mechanism underlying clinical KS variation. We investigated the gut microbiota composition of 23 individuals with KS (patients) and 40 of their family members, to test whether (1) variation in the gut microbiota associates with KS diagnosis and (2) variation within the gut microbiota relates with KS syndrome symptoms. Both alpha and beta diversity of patients were different from their family members. Genus Coprococcus 3 was lower in abundance in patients compared to family members. Moreover, abundance of genus Merdibacter was lower in patients versus family members, but only in participants reporting intestinal complaints. Within the patient group, behavioral problems explained 7% of beta diversity variance. Also, within this group, we detected higher levels of Atopobiaceae – uncultured and Ruminococcaceae Subdoligranulum associated with higher symptom severity. These significant signatures in the gut microbiota composition in patients with KS suggest that microbiota differences are part of the KS phenotype.     

长春地区428例儿童遗传咨询者细胞遗传学临床分析

为了解儿童先天遗传性疾病的发病情况,对428例患儿进行常规接种、培养及制备外周血淋巴细胞染色体G显带标本分析.结果表明,428例患儿中染色体异常143例,异常检出率为33.41%,涉及异常核型20余种.143例异常染色体患者中常染色体异常134例,性染色体异常9例.在常染色体疾病中最常见的为21-三体综合征,其次为9号染色体异常、22号染色体异常.提示染色体核型分析是诊断染色体病以及检出携带者的主要方法.     

A missense variant,p.(Ile269Asn), in MC4R as a secondary finding in a child with BCL11A-related intellectual disability

We describe a three year old female who underwent clinical exome sequencing and was diagnosed with BCL11A-related intellectual disability/Dias-Logan syndrome due to a de novo, heterozygous variant in the BCL11A gene, NM_018014.3:c.148C > T; p.(Gln50*). A missense variant in MC4R, NM_005912.3:c.806T > A; p.(Ile269Asn), was also reported as a secondary finding. In her family, her father, paternal aunt, and paternal uncle were all reported to have height and weight measurements suggestive of Class 3 obesity with BMI>40 kg/m². The MC4R gene is not currently listed among those recommended for reporting of secondary findings by the American College of Medical Genetics and Genomics (ACMG). The identification of genetic risk factors for obesity is an emerging field without established guidelines for the care of patients who are found to have a predisposing genetic variant for obesity as a secondary finding. Management suggestions include interventions for weight-management, early screening for obesity-related co-morbidities, such as diabetes and dyslipidemia, and targeted therapies, such as MC4R agonists.     

Analysis of clinical manifestation and genetic mutations in two patients with Cornelia de Lange syndromeCSCD

Objective: To detect potential mutations in two neonates suspected for Cornelia de Lange syndrome (CdLS). Methods: Peripheral blood samples from the neonates and their parents were collected and analyzed for CdLS-related genes using targeted sequence capture and next-generation sequencing. Suspected mutations were confirmed by direct Sanger sequencing. Results: The neonates were found to respectively carry mutations c. 7219C>T and p. D2339Lfs ∗ 4 of the NIPBL gene, among which the p. D2339Lfs ∗ 4 mutation has not been reported previously. No pathogenic mutation was found in other CdLS-related genes including NIPBL, SMC1A, SMC3, RAD21 and HDAC8. Conclusion: The c. 7219C>T and p. D2339Lfs ∗ 4 mutations of the NIPBL gene probably account for the disease in both patients. © 2018 MeDitorial Ltd. All rights reserved.     

三例22号染色体异常胎儿的产前遗传学分析

目的应用超声以及多种遗传学检测技术对3例产前筛查提示染色体可能异常的胎儿进行分析,为遗传咨询提供依据。方法对3例孕妇进行胎儿超声检查、核型分析、单核苷酸多态性微阵列芯片(single nucleotide polymorphism-based microarray,SNP-Array)检测,并通过荧光原位杂交(fluorescence in situ hybridization,FISH)对结果进行验证。结果三例胎儿均发现22号染色体存在异常。例1在22q13.2q13.33区存在7.1 Mb的杂合缺失,涉及SHANK3、FBLN1等54个OMIM基因;例2为嵌合体核型,约12%的细胞22q13.31q13.33区存在6.6 Mb的杂合缺失,覆盖SHANK3、PPARA等48个OMIM基因,另有5%的细胞22q11.1q13.2区存在26.1 Mb的拷贝重复,覆盖285个OMIM基因;例3在22q11.1q11.21区存在1.7 Mb的二次重复,涉及CECR1、CECR2、ATP6V1E1等10个OMIM基因。三例胎儿父母的核型及SNP-Array检测结果均未见异常,提示胎儿为新发变异。结论22号染色体微缺失/微重复所致疾病的严重性不仅与其范围有关,还与染色体结构、基因剂量及环境等密切相关。在产前诊断中综合运用超声和多种遗传学检测技术可以显著提高表型变异较大的遗传学异常的检出率。