先天性内耳畸形与SLC26A4基因相关性的研究

目的分析婴幼儿、儿童先天性感音神经性聋(sensorineural hearing loss,SNHL)中先天性内耳畸形患儿的SLC26A4基因突变发生的概率,突变类型以及基因突变与各种内耳畸形之间的关系。方法回顾性分析125例(225耳)先天性内耳畸形的SNHL患儿的影像学及听力学资料,收集其中77例先天性内耳畸形患儿及正常对照组100例的外周血。提取基因组DNA,聚合酶链反应扩增SLC26A4,直接测序分析突变。结果 77例样本中79.2%(42/53)的前庭导水管扩大组、90%(9/10)的Mondini畸形组、7.1%(1/14)其他内耳畸形组中的患者发现有SLC26A4基因突变。共发现SLC26A4基因突变类型16种,其中4种为新发现的类型。69.8%(44/63)前庭导水管扩大(enlarged vestibular aqueduct,EVA)和Mondini畸形组中发现c.919-2A>G(IVS7-2A>G)突变,等位基因突变频率50%(63/126),是SLC26A4基因最常见的突变类型。EVA组和Mondini组分别与正常对照组等位基因突变频率比较差异有显著性(P=0.000,P<0.01)。结论 SLC26A4基因突变是EVA和Mondini畸形的主要原因之一,c.919-2A>G(IVS7-2A>G)是最常见的突变类型。     

Cross-sectional multicenter study of patients with urea cycle disorders in the United States

Inherited urea cycle disorders comprise eight disorders (UCD), each caused by a deficiency of one of the proteins that is essential for ureagenesis. We report on a cross-sectional investigation to determine clinical and laboratory characteristics of patients with UCD in the United States. The data used for the analysis was collected at the time of enrollment of individuals with inherited UCD into a longitudinal observation study. The study has been conducted by the Urea Cycle Disorders Consortium within the Rare Diseases Clinical Research Network (RDCRN) funded by the National Institutes of Health. One-hundred eighty-three patients were enrolled into the study. Ornithine transcarbamylase (OTC) deficiency was the most frequent disorder (55%), followed by argininosuccinic aciduria (16%) and citrullinemia (14%). Seventy-nine percent of the participants were white (16% Latinos), and 6% were African American. Intellectual and developmental disabilities were reported in 39% with learning disabilities (35%) and half had abnormal neurological examination. Sixty-three percent were on a protein restricted diet, 37% were on Na-phenylbutyrate and 5% were on Na-benzoate. Forty-five percent of OTC deficient patients were on l-citrulline, while most patients with citrullinemia (58%) and argininosuccinic aciduria (79%) were on l-arginine. Plasma levels of branched-chain amino acids were reduced in patients treated with ammonia scavenger drugs. Plasma glutamine levels were higher in proximal UCD and in neonatal type disease. The RDCRN allows comprehensive analyses of rare inherited UCD, their frequencies and current medical practices.     

Fits of laughter (gelastic epilepsy) with a tumour of the floor of the third ventricle

Summary A patient with fits of laughter due to a tumorous alteration (hyperplasia) of the floor of the third ventricle is described with electroencephalographic findings indicative of focal epilepsy (complex partial seizures = psychomotor fits). The laughter is interpreted as an inborn emotional expression with structural substrate in the hypothalamus and neighboring brain. With structures remaining intact functional disorders in this area can cause epileptic phenomena with participation of the limbic system.In cooperation with the Deutsche Forschungsgemeinschaft     

32 例高苯丙氨酸血症鉴别诊断分析

目的对32例新生儿高苯丙氨酸血症（hyperphenylalaninemia,HPA）进行鉴别分析。方法203_1年1月至2013年2月,四川省新生儿筛查中心共确诊32例HPA。通过尿蝶呤谱分析、红细胞二氢蝶啶还原酶测定、BH。负荷实验和串联质谱分析,进一步鉴别诊断。结果32例HPA新生儿中,1例四氢生物蝶呤缺乏症,3例经典型苯丙酮尿症（classicalphenylke-touria,CPKU）,15例轻度PKU,11例轻度HPA,1例枫糖尿病,1例希特林蛋白缺乏症。结论对所有HPA必须进行鉴别分析,尽早确诊和治疗。     

Somatic mosaicism in inborn errors of immunity: Current knowledge,challenges, and future perspectives

Inborn errors of immunity (IEI) are a diverse group of monogenic disorders of the immune system due to germline variants in genes important for the immune response. Over the past decade there has been increasing recognition that acquired somatic variants present in a subset of cells can also lead to immune disorders or ‘phenocopies’ of IEI. Discovery of somatic mosaicism causing IEI has largely arisen from investigation of seemingly sporadic cases of IEI with predominant symptoms of autoinflammation and/or autoimmunity in which germline disease-causing variants are not detected. Disease-causing somatic mosaicism has been identified in genes that also cause germline IEI, such as FAS, and in genes without significant corresponding germline disease, such as UBA1 and TLR8. There are challenges in detecting low-level somatic variants, and it is likely that the extent of the somatic mosaicism causing IEI is largely uncharted. Here we review the field of somatic mosaicism leading to IEI and discuss challenges and methods for somatic variant detection, including diagnostic approaches for molecular diagnoses of patients.     

The hidden Niemann-Pick type C patient: clinical niches for a rare inherited metabolic disease

Background: Niemann-Pick disease type C (NP-C) is a rare, inherited neurodegenerative disease of impaired intracellular lipid trafficking. Clinical symptoms are highly heterogeneous, including neurological, visceral, or psychiatric manifestations. The incidence of NP-C is under-estimated due to under-recognition or misdiagnosis across a wide range of medical fields. New screening and diagnostic methods provide an opportunity to improve detection of unrecognized cases in clinical sub-populations associated with a higher risk of NP-C. Patients in these at-risk groups (“clinical niches”) have symptoms that are potentially related to NP-C, but go unrecognized due to other, more prevalent clinical features, and lack of awareness regarding underlying metabolic causes.

Methods: Twelve potential clinical niches identified by clinical experts were evaluated based on a comprehensive, non-systematic review of literature published to date. Relevant publications were identified by targeted literature searches of EMBASE and PubMed using key search terms specific to each niche. Articles published in English or other European languages up to 2016 were included.

Findings: Several niches were found to be relevant based on available data: movement disorders (early-onset ataxia and dystonia), organic psychosis, early-onset cholestasis/(hepato)splenomegaly, cases with relevant antenatal findings or fetal abnormalities, and patients affected by family history, consanguinity, and endogamy. Potentially relevant niches requiring further supportive data included: early-onset cognitive decline, frontotemporal dementia, parkinsonism, and chronic inflammatory CNS disease. There was relatively weak evidence to suggest amyotrophic lateral sclerosis or progressive supranuclear gaze palsy as potential niches.

Conclusions: Several clinical niches have been identified that harbor patients at increased risk of NP-C.     

串联质谱技术对新生儿遗传代谢病的筛查及随访研究

目的 初步了解串联质谱筛查新生儿遗传代谢病的发生率及确诊病例的随访情况.方法 采用串联质谱方法,对129 415例新生儿进行26种氨基酸、有机酸及脂肪酸代谢性疾病筛查,对确诊病例进行流行病学特点、预后及随访情况进行分析.结果 确诊新生儿遗传代谢病23例,包括氨基酸代谢异常13例、有机酸代谢异常6例及脂肪酸代谢异常4例,发病率为1∶5626.筛查的阳性预测值为2.10％,特异性为99.72％,敏感性为100％.所有确诊病例进行随访,仅有6例出现运动、智力发育落后及代谢紊乱.结论 串联质谱方法能够早期筛查、诊断遗传代谢病,及早干预预后较好;串联质谱筛查方法具有较高的特异性及敏感性,但阳性预测值低,需要进一步提高筛查效率.     

应用高分辨率熔解曲线分析快速筛查和诊断citrin缺陷导致的新生儿肝内胆汁淤积症

目的 探讨高分辨率熔解曲线(high-resolution melting,HRM)分析技术用于citrin缺陷导致的新生儿肝内胆汁淤积症(neonatal intrahepatic cholestasis caused by citrin deficiency,NICCD)筛查和诊断的可行性.方法 根据中国人群SLC25A13基因的热点突变类型(851del4、1638ins23、IVS6+5G＞A和IVS16ins3kb)设计特异性HRM扩增引物,挑选经测序证实的50名正常对照和20例NICCD患儿,建立和完善HRM检测条件.用优化后的HRM检测方法对171例临床疑似的NICCD患者进行HRM筛查.若受检样本的熔解曲线与阳性质控样品相吻合,则进行DNA测序分析.结果 优化后的HRM方法能准确地对50名正常对照及20例NICCD患儿进行基因分型,其灵敏度和特异性均为100％ (70/70).重复实验表明,相同基因型的不同样品HRM熔解曲线完全吻合,重复性好.在171例疑似患儿中,有7例患儿熔解曲线与阳性质控样品基因型相符,其HRM基因分型为:1例851del4纯合突变,1例IVS6+5G＞A杂合突变,3例851del4杂合突变,1例[IVS6+5G＞ A]+[851del4],1例[1638ins23+IVS16ins3kb]+[1638ins23].DNA测序证实了HRM基因分型,准确率为100％.结论 HRM技术具有高通量、操作简便、结果准确、重复性好等优点,可对临床疑似的NICCD患儿进行基因筛查和诊断.