OPHN1 基因突变致X 连锁智力障碍1 例报告及文献复习

目的探讨X连锁智力障碍的临床表型与基因型的关系。方法回顾分析1例癫痫伴智力障碍患儿的临床资料以及全外显子捕获测序结果。结果男性患儿,9岁。生后4个月发现发育迟缓,5个月癫痫发作,4岁时智力发育障碍,7岁时视力检查提示高度近视。脑电图提示癫痫样放电;头颅磁共振提示大枕大池;韦氏儿童智力量表评估示总智商49。基因检测发现患儿OPHN1基因第19号外显子存在移码突变c.1641delA(p.K547fs*5),家系共分离验证发现其母亲携带该变异位点。该变异位点既往未见报道。根据ACMG指南,其为致病性变异。患儿经抗癫痫药物丙戊酸钠联合拉莫三嗪治疗,效果好。结论 OPHN1移码突变c.1641delA(p.K547fs*5)为患儿X连锁智力障碍的致病基因,临床表型为癫痫、中度智力低下、高度近视、大枕大池。     

脆性X综合征的筛查与诊断

脆性Ｘ综合征是引起先天性智力低下常见疾病，仅次于Ｄｏｗｎ综合征，由家族性智力低下基因（ＦＭＲ）－１动态突变引起，具有独特的遗传方式和临床表现，本文综述了疾病有关细胞遗传学，分子生物学和免疫细胞化学方面的筛查及诊断方法。     

孤独症患儿甲基化CpG结合蛋白2基因突变研究

目的 了解孤独症患儿甲基化CpG结合蛋白2基因(MeCP2基因)的突变情况,探讨MeCP2基因在孤独症发病中的作用.方法 2004-2007年对中国医科大学附属盛京医院发育儿科的30例男性孤独症患儿(年龄2.5～5.5岁)进行研究.患者生后16～22个月起出现发育倒退(语言、社交倒退)、兴趣狭窄及刻版行为,经检查符合DSM-IV孤独症的诊断标准.根据文献对MeCP2基因编码外显子及侧翼序列设计引物,PCR扩增,产物纯化后直接测序.结果 对30例患儿进行MeCP2基因编码区的突变检测,未发现编码区突变.结论 MeCP2基因编码区突变可能不是孤独症的主要机制,有必要对孤独症患儿进行MeCP2基因的非编码区及调控区的突变分析.     

发根脆性X智力低下蛋白检测法诊断脆性X综合征

目的：至今已有多种筛查和诊断脆性X综合征(fragile X syndrome,FXS)的方法,以PCR法和Southern印迹方法应用最广,然而每种方法均存在各自的局限性。该研究探讨发根脆性X智力低下蛋白（fragile X mental retardation protein,FMRP）检测在诊断或筛查FXS中的可靠性,以建立一种快速、简便、价廉且可靠的诊断FXS的方法。方法：采用发根FMRP免疫组化的检测方法对80例健康儿童、40例不明原因智力低下儿童、已确诊FXS家系成员12例进行检查; 用7-deza-dGTP PCR 法进行对照,探讨其对诊断FXS的应用价值。结果：在80例健康儿童中,发根FMRP的表达率均在80%以上。40例不明原因智力低下患儿中,2例确诊为FXS患儿的发根FMRP表达率分别为10%和0,另38例非FXS患者发根FMRP的表达率均在80%以上。在FXS家系调查中,确诊的2例FXS患者的发根FMRP表达率均为0。结论：发根FMRP检测诊断FXS具有快速、简便、价廉、可靠等特点,值得进一步推广应用。［中国当代儿科杂志,2009,11（10）：817-820］     

儿童Lowe综合征OCRL基因突变2例报告

目的探讨儿童Lowe综合征的临床特点和基因特征。方法分析2例Lowe综合征患儿的临床资料和OCRL基因检测结果,并复习相关文献。结果 2例患儿均为男性,均存在小分子蛋白尿、高钙尿症、佝偻病和肾结石。例2患儿还有轻度代谢性酸中毒、糖尿和隐睾症。例1患儿生后不久发现有视力异常和先天性白内障,并行手术治疗,同时存在精神运动发育落后,头颅磁共振成像(MRI)示胼胝体发育不良。例2患儿就诊时肾外症状不明显,但眼科检查发现有先天性白内障,头颅MRI示脑发育低下、脑白质髓鞘化延迟,且随访过程中逐渐出现智力发育落后。OCRL基因检测发现2个突变,例1为剪切位点突变NG 008638.1:g.46846-46848del TAA/ins C,例2为缺失移码突变NM000276.3:c.321del C,两种突变以前文献均未报道。结论 Lowe综合征的诊断主要通过临床表现和OCRL基因检测,对于有先天性白内障、肾小管病变的患儿需要与Lowe综合征鉴别。本研究发现2个OCRL基因的新突变。     

小儿Sjögren-Larsson综合征临床特征及基因突变分析

目的 分析4例 Sjögren-Larsson 综合征 （Sjögren-Larsson syndrome, SLS）患儿临床特征及ALDH3A2基因突变, 以明确诊断, 并为遗传咨询和产前诊断提供依据。方法 收集 2008—2013 年中国人民解放军总医院儿童医学中心收治的 4 例 Sjögren-Larsson 综合征患儿的临床资料。抽取外周静脉血各3 mL, 应用二氧化硅法提取基因组DNA。采用聚合酶链反应（PCR）扩增ALDH3A2基因的11个外显子及其与内含子的连接区。PCR产物直接测序法检测基因突变。结果 来自3个家系的4例患儿均存在先天性鱼鳞病、智力低下、痉挛性截瘫或四肢瘫等典型临床表现。3例患儿 ALDH3A2基因测序均检出基因突变。分别为：例1, IVS5-1del G, c.1157A＞G（p.Asn386Ser）; 例2和例3, c.1157A＞G （p.Asn386Ser）纯合突变; 例4基因检测未发现编码区致病突变。结论 明确了 4 例 Sjögren-Larsson综合征患儿的基因诊断, 发现 2个ALDH3A2基因突变位点,其中 IVS5-1del G为新发突变。     

原钙黏蛋白19基因突变致限于女性的癫痫伴智力低下临床特点分析

目的分析以限于女性的癫痫伴智力低下为临床特点的原钙黏蛋白19(PCDH19)基因突变的临床及遗传学特点。方法回顾分析1例PCDH19基因突变致癫痫伴智力低下女性患儿的临床资料。结果 1岁11个月女性患儿,癫痫发作并存在热敏感,发作有丛集性,形式多样,伴智力落后、孤独症样表现。基因测序发现PCDH19新发突变。发作间期脑电图见右侧额中央及中线区少量尖波。头颅磁共振无明显异常。抗癫痫药物治疗效果差。结论限于女性的癫痫伴智力低下发作有热敏感、丛集性特点,早期行癫痫基因检测有助于明确诊断,提供遗传咨询。     

脆性X综合征的临床及细胞遗传学研究：附两家系分析

应用FUdR及Caffein诱导方法检出两家族共8例脆性X综合征患者,4例携带者。指出,智力低下伴多动、大耳朵及不明原因的癫病发作是青春期前患者进行脆性X检查的临床指征。     

MKS1 基因变异所致Joubert 综合征1 例临床及基因分析

目的对Joubert 综合征进行临床特点和遗传学分析。方法回顾分析1例确诊的Joubert 综合征患儿的临床资料。结果患儿男性,3个月,双眼不追视、发育落后,四肢肌张力偏低。头颅磁共振示"磨牙征"。全外显子测序显示患儿MKS1基因c.1411_c.1412insG及c.44AG复合杂合突变。Sanger测序验证c.1411_c.1412insG移码突变来自于父亲,已有报道;c.44AG错义突变来自于母亲,未见报道,根据ACMG指南为可能致病变异。患儿确诊为Joubert综合征。结论确诊患儿为Joubert综合征,新发现c.44AG错义突变。     

脆性X综合征的筛查与诊断

脆性Ｘ综合征是引起先天性智力低下常见的疾病，仅次于Ｄｏｗｎ综合征，由家族性智力低下基因（ＦＭＲ）－１动态突变引起，具有独特的遗传方式和临床表现。本文综述了该疾病有关细胞遗传学、分子生物学和免疫细胞化学方面的筛查及诊断方法。     

Lessons from fragile X regarding neurobiology, autism, and neurodegeneration

The fragile X mental retardation 1 gene (FMR1) mutation causes two disorders: fragile X syndrome (FXS) in those with the full mutation and the fragile X-associated tremor/ataxia syndrome (FXTAS) in some older individuals with the premutation. FXS is caused by a deficiency of the FMR1 protein (FMRP) leading to dysregulation of many genes that create a phenotype with ADHD, anxiety, and autism. FXTAS is caused by the elevation of FMR1-mRNA to levels 2 to 8 times normal in the premutation. This causes an RNA gain of function toxicity leading to brain atrophy, white matter disease, neuronal and astrocytic inclusion formation, and subsequent ataxia, intention tremor, peripheral neuropathy, and cognitive decline. The neurobiology and pathophysiology of FXS and FXTAS are described in detail.     

孤独症儿童脆性位点精神发育迟滞1基因检测

目的对孤独症儿童进行脆性位点精神发育迟滞1(FMR-1)基因检测,探讨儿童孤独症与FMR-1基因的关系。方法孤独症患儿75例。用一般情况调查表进行调查,以儿童孤独症评定量表、孤独症行为检查量表筛查可疑患儿,按照中国精神障碍分类与诊断标准第3版(CCMD-3)的儿童孤独症诊断标准进行诊断和FMR-1基因检测。结果孤独症患儿FMR-1基因异常率极低,仅1.3%。结论儿童孤独症遗传学发病机制可能与FMR-1基因无关。     

Autistic spectrum disorder and the fragile X premutation

Fragile X syndrome (FXS) is the most common inherited cause of mental retardation. It is also one of the most common identifiable causes of Autism Spectrum Disorder (ASD). Carriers of FXS are often considered to be cognitively and behaviorally unaffected. However, we report here on six individuals in the premutation range who also have ASD. A comparison is made with five subjects in the premutation range who did not receive a diagnosis of ASD. The six individuals with ASD had a range of cognitive ability levels from no impairment to moderate retardation. Discussion includes the impact of molecular variables including lowered FMR1 protein and elevated FMR1 mRNA in addition to environmental factors leading to the complex neurodevelopmental disorder of ASD.     

Discovery of the gene makes the direct molecular genetic diagnosis of Martin-Bell syndrome possible]

FORMULATION OF QUESTION: In 1991 four independent groups of geneticists succeeded in replacing the comparatively unreliable cytogenetic and indirect molecular diagnostics of the X-linked Martin-Bell-syndrome (MBS) by a more accurate approach. METHODS AND RESULTS: Fine structure analysis of the disease locus at Xq 27.3 led to the discovery of the fragile X mental retardation gene I (FMR I-gene), the mutative changes of which are responsible for the disease and can easily be detected in Southern hybridizations with gene probes out of this area. The observed changes are strong amplification of a repetitive CGG-motive in exon I of the gene in patients, a more moderate one in symptom-free carriers of the disease and changes in the promotor region of the gene to a varying extent in patients and carriers. CONCLUSION: This direct molecular diagnosis of MBS enables a safe identification of patients and carriers of the disease. A combined analysis of the observed mutations makes possible prenatal diagnosis, discriminating between carriers with and without symptoms. Especially this is necessary, since 20% of male and 50 to 70% of female mutation carriers are phenotypically normal.     

Don’t miss patients with atypical FMR1 mutations: dysmorphism and clinical features in a boy with a partially methylated FMR1 full mutation

Fragile X syndrome characterized by intellectual disability (ID), facial dysmorphism, and postpubertal macroorchidism is the most common monogenic cause of ID. It is typically induced by an expansion of a CGG repeat in the fragile X mental retardation 1 (FMR1) gene on Xq27 to more than 200 repeats. Only rarely patients have atypical mutations in the FMR1 gene such as point mutations, deletions, or unmethylated/partially methylated full mutations. Most of these patients show a minor phenotype or even appear clinically healthy. Here, we report the dysmorphism and clinical features of a 17-year-old boy with a partially methylated full mutation of approximately 250 repeats. Diagnosis was made subsequently to the evaluation of a FMR1 premutation as the cause for maternal premature ovarian failure. Dysmorphic evaluation revealed no strikingly long face, no prominent forehead/frontal bossing, no prominent mandible, no macroorchidism, and a head circumference in the lower normal range. Acquisition of a driving license for mopeds and unaccompanied rides by public transport in his home province indicate rather mild ID (IQ?=?58). Conclusion: This adolescent demonstrates that apart from only minor ID, patients with a partially methylated FMR1 full mutation present less to absent pathognomonic facial dysmorphism, thus emphasizing the impact of family history for a straightforward clinical diagnosis.     

Two boys with fragile x syndrome and hepatic tumors

Hepatic tumors are rare childhood neoplasms with uncertain etiology. We report the cooccurrence of hepatic tumors in 2 boys with fragile X syndrome, one with hepatoblastoma and another with desmoplastic nested spindle cell tumor of liver. The pathogenesis of fragile X syndrome involves silencing of the fragile X mental retardation 1 gene and consequent loss of FMR1 protein. We speculate regarding molecular pathways that might explain the cooccurrence of the 2 conditions. Further examination of a possible functional link between hepatic neoplasia and loss of FMRP is warranted.     

脆性X综合征患儿细胞内环磷酸腺苷降低的机制

目的 探讨脆性X综合征细胞内环磷酸腺苷(cAMP)降低的机制。方法 通过基因封闭方法，建立Fra(X)细胞模型，研究cAMP代谢途径中的两个关键酶腺苷酸环化酶(AC)及磷酸二酯酶(PDE)的活性变化。结果 试验组AC的比活力明显低于对照组(P＝0．000)，而PDE比活力则无显著改变(P＝0．983)。结论 Fra—(X)细胞内cAMP水平的降低可能与AC活性的抑制有关，而与PDE活性无明显关系。     

Sotos综合征的临床表型及遗传学分析

3例男性患儿,年龄7~13个月,均以运动发育迟缓、智力落后就诊,均有前额突出、眼距宽或者下颌尖长等特殊面容,身长和头围方面仅病例1的头围超过2 SD,其中2例患儿的骨龄超前、1例患儿脑电图异常,3例患儿头部CT均显示脑室扩大。全基因组芯片分析发现1例患儿染色体5q35.2区域缺失一个1.75 Mb大小的拷贝,其中包括NSD1基因;荧光定量PCR方法对拷贝数异常区域进行验证：NSD1基因拷贝数减半。高通量测序分析发现另2例患儿的NSD1基因分别存在c.1157T > G杂合突变和c.1177G > T杂合突变,其中c.1157T > G杂合突变未见报道,但生物信息学分析提示该位点突变具有致病性。因此,3例患儿均确诊为Sotos综合征。Sotos综合征是常染色体显性遗传的先天性生长过度症,70%~90%的患者存在NSD1基因突变,约10%存在染色体5q35区域（包括NSD1基因）缺失。