IFNGR1基因突变致分枝杆菌易感性疾病2例病例报告

目的：探讨IFNGR1基因突变致分枝杆菌易感性疾病（MSMD）的临床特征。方法：总结2例IFNGR1基因突变MSMD患儿的临床特征,ELISA方法检测干扰素-γ（IFN-γ）释放功能,流式细胞术检测IFNGR1蛋白表达,Sanger测序方法分析IFNGR1基因突变。结果：①2例患儿均生后3月龄内出现卡介苗病,以卡介苗接种侧腋下淋巴结肿大为初始表现,并逐渐播散累及肺部、肠道、中枢和骨髓。确诊年龄分别为4岁和6岁。常规免疫功能（淋巴细胞亚群、免疫球蛋白、中性粒细胞呼吸爆发功能和补体）评估未见缺陷。②2例患儿的IFN-γ释放能力明显低下、IFNGR1蛋白表达均低于正常。③1例存在c.665 G>A（p.G219R）纯合突变,其父母均为c.665 G>A（p.G219R）杂合突变;1例存在c.665 G>A（p.G219R）和c.310 C>A（p.A104N）复合杂合突变,分别遗传自患儿母亲［c.665 G>A（p.G219R）杂合突变］及父亲［c.310 C>A（p.A104N）杂合突变］。其中1例患儿的突变为新发突变,既往无文献报道。④2例患儿在确诊前抗痨治疗效果不佳,确诊后加用IFN-γ,卡介苗感染得到控制,未见其他不良反应。结论：IFNGR1基因突变可导致MSMD。卡介苗病患儿常规免疫评估无缺陷时,需考虑该病可能,相关蛋白检测、IFN-γ释放实验和基因分析有助于诊断。IFN-γ治疗有一定疗效。     

中国人多种羧化酶缺陷症患儿4例及其父母基因突变分析

目的研究中国人多种羧化酶缺陷症（multiple carboxylase deficiency,MCD）患儿及其父母基因突变情况。方法应用聚合酶链反应-直接测序的方法,对4例临床确诊MCD的中国患儿的生物素酶（BT）基因和全羧化酶合成酶（HLCS）基因的各个外显子及其两侧侧翼序列进行突变的检测,并对其父母进行相应突变基因检测。结果4例患儿皆为HLCS基因突变,没有发现BT基因突变。共发现1个缺失突变：780de1G,3个错义突变：1522C〉T（R508W）、1367A〉G（Y456C）和1900G〉A（I）634N）。例1为HLCS基因的第11号外显子上的1522C〉T的错义突变,为纯合突变;例2为第11号外显子的1522C〉T和第9号外显子的1367A〉G的复合性杂合突变;例3为第11号外显子的1522C〉T和第13号外显子的1900G〉A的复合性杂合突变;例4为第11号外显子的1522C〉T和第7号外显子的780de1G的复合性杂合突变;4例患儿的父母均是突变基因携带者。结论R508W突变可能是中国MCD中HLCS缺陷患儿较常见的突变。     

SSBP1基因突变致常染色体显性视神经萎缩症伴慢性肾功能不全1例并文献复习

对2021年7月郑州大学附属儿童医院收治的1例SSBP1基因突变致常染色体显性视神经萎缩症(ADOA)伴慢性肾功能不全患儿的临床资料进行回顾性分析, 并复习相关文献。患儿, 女, 10岁, 因"发现生长迟缓3年, 血肌酐升高2年"就诊。身高130 cm(低于健康同龄同性别第10百分位), 体重22 kg(低于健康同龄同性别第3百分位)。尿素16.3 mmol/L, 肌酐115.4 μmol/L, 估算肾小球滤过率41 mL/(min·1.73 m2), 伴代谢性酸中毒、轻度贫血;影像学示双肾体积小, 实质回声增强, 内可见散在点状高回声, 皮髓质分界不清。患儿有视神经萎缩病史。患儿父亲、母亲无相关表型, 患儿基因检测示c.320G>A(p.R107Q)杂合子错义突变, 为自发突变。共检索到文献5篇, 均为英文。SSBP1的基因突变共8种, 含杂合子错义突变7种:c.320G>A(p.Arg107Gln)、c.119G>T (p.Gly40Val)、c.331G>C(p.Glu111Gln)、c.184A>G(p.Asn62Asp)、c.113G>A(...     

原发性肉碱缺乏症的筛查与患者SLC22A5基因突变分析北大核心CSCD

目的探讨原发性肉碱缺乏症（pfimary camitine deficiency,PCD）患者的临床特点和SLC22A5基因突变情况。方法利用液相（色谱）串联质谱技术对徐州市2015年9月至2017年12月出生的210908例新生儿和576例临床遗传代谢病疑似患儿进行游离肉碱及酰基肉碱检测,对游离肉碱降低的患儿进行SLC22A5基因突变分析以确诊。对确诊患儿的临床表现、生化特点、基因特点及治疗预后进行分析,并采用配对样本t检验对患儿治疗前后的生化指标进行比较。结果共确诊10例PCD患儿（其中9例来自新生儿筛查,1例来自临床患儿）和7例母源性肉碱缺乏症患者,口服左卡尼汀治疗后血游离肉碱和其他酰基肉碱水平恢复正常。1例来自临床患儿的临床症状消失,16例来自新生儿筛查的患儿无任何临床症状,生长发育正常。17例患儿均进行基因突变检测,共检出10种突变类型,分别为c．1400C〉G、c．1462C〉T、c．797C〉T、c．95A〉G、c．92C〉T、c．1093A〉C、c．761G〉A、c．865C〉T、c．428C〉T、c．1195C〉T,其中c．1093A〉C和c．92C〉T为新突变,c．1400C〉G为最常见的突变类型。结论液相（色谱）串联质谱技术可筛查出新生儿及母源性肉碱缺乏症患者,徐州地区c．1400C〉G突变出现频率最高,早期治疗预后良好。     

青岛市苯丙氨酸羟化酶缺乏症患儿基因突变分析

目的探讨青岛市苯丙氨酸羟化酶(phenylalanine hydroxylase,PAH)缺乏症患儿的基因突变特点,为青岛市PAH缺乏症的产前诊断、治疗提供科学参考依据。方法对经青岛市新生儿疾病筛查确诊的44例PAH缺乏症患儿,应用第二代高通量测序及多重连接酶探针依赖扩增(multi-ligase probe dependent amplification,MLPA)技术进行基因分析,检测患儿基因突变位点,应用Sanger测序对其父母的PAH基因相应突变位点进行检测并验证。根据患儿血苯丙氨酸浓度,分为经典型苯丙酮尿症、轻度苯丙酮尿症和轻度高苯丙氨酸血症。结果①44例PAH缺乏症患儿PAH基因中均检测到2个突变位点,其中2例为纯合突变,纯合突变的频率为4.6%,所有突变在患儿父母相应突变位点处均能检测到。②44例PAH缺乏症患儿共检测到突变36种,其中c.728G>A突变频率最高(15.9%,14/88),其次是c.1068C>A(10.2%,9/88),再次为c.158G>A(9.1%,8/88)。③21例经典型苯丙酮尿症患儿PAH基因突变19种,其中c.1068C>A突变频率最高(21.4%,9/42),其次是c.728G>A(19.0%,8/42)。10例轻度苯丙酮尿症患儿PAH基因突变14种,其中c.721C>T/722delG突变频率最高(15.0%,3/20),其次为c.1197A>T、c.1301C>A、c.721C>T、c.728G>A(均为10.0%,2/20)。13例轻度高苯丙氨酸血症患儿PAH基因突变17种,其中c.158G>A突变频率最高(26.9%,7/26),其次为c.728G>A(15.4%,4/26)。结论青岛市PAH缺乏症患儿PAH基因突变以复合杂合突变为主,具有明显热点突变(c.728G>A、c.1068C>A、c.158G>A),经典型苯丙酮尿症患儿以c.1068C>A、c.728G>A为主,轻度苯丙酮尿症患儿以c.721C>T/722delG为主,轻度高苯丙氨酸血症患儿以c.158G>A为主。本研究明确了青岛市PAH缺乏症患儿基因的突变类型与特点,为深入开展PAH缺乏症的诊断以及进一步的基因治疗奠定了基础。     

糖原累积病Ib型患儿基因突变分析与临床研究

目的：糖原累积病Ib型（GSDIb）是由于SLC37A4基因突变引起葡萄糖-6-磷酸转移酶（G6PT）活性缺陷所致,该病患者大部分有反复感染及炎症性肠病的发生,预后较差。SLC37A4基因的检测对GSDIb患者的诊断、分型、预测患者的预后尤为重要。本文旨在研究糖原累积病Ib型患儿SLC37A4基因突变的情况,探讨基因型与临床表型的关系。方法：应用聚合酶链反应直接测序的方法,对拟诊GSDIb型的28例患儿行SLC37A4基因外显子及其相邻区域的突变筛查。结果：7例患儿检测到SLC37A4基因突变,检出率为25% (7/28例),包括错义突变：p.Gly149Glu（9/13,69%）、p.Gly115Arg（1/13,8%）、p.Pro191Leu（1/13,8%）;移码突变：c.959-960 insT（1/13,8%）;剪接突变：c.870+5G>A（1/13,8%）。结论：c.959-960 insT为新突变,p.Gly149Glu为本研究最常见的突变,p.Gly149Glu突变可能与患儿的严重感染相关。     

LIPA基因突变致迟发型胆固醇酯贮积病1例

7岁1月龄患儿因“发现肝功能异常4年”就诊。体格检查发现肝脾肿大,组织病理学表现为肝脂肪变性和肝纤维化。基因检测提示LIPA基因存在复合杂合突变：c.860G>A（p.G287E）和c.796G>T（p.G266*）,分别来源于父亲和母亲,进一步完善溶酶体酸性脂肪酶活性测定提示明显降低,诊断为LIPA基因突变导致的迟发...     

Holocarboxylase synthetase deficiency induced by HLCS gene mutations: a rare disease study北大核心CSCD

男性患儿,16月龄,因发现头面部红斑15个月,外阴红斑10个月,加重5 d就诊。患儿新生儿期即出现口周、眼周红斑,婴儿期出现颈部、腋下、外阴三角区等腔口和皱褶部位的红斑、丘疹,可见脱屑和糜烂。血气分析提示代谢性酸中毒,血遗传代谢病氨基酸和酰基肉碱谱分析、尿液有机酸分析结果均提示多种羧化酶缺乏症,基因检测结果提示HLCS基因存在c.1522C>T(p.R508W)纯合突变。最终该患儿诊断为全羧化酶合成酶缺乏症,口服生物素治疗取得良好的临床疗效。该文总结了1例全羧化酶合成酶缺乏症患儿的临床资料,对其病因、诊断、治疗进行归纳总结,为临床医生诊断该类罕见疾病提供思路。     

多种羧化酶缺乏症的诊断及基因突变研究进展

多种羧化酶缺乏症是由于生物素酶或全羧化酶合成酶缺乏所致的有机酸代谢紊乱疾病,临床主要表现为神经系统及皮肤损害.串联质谱分析血3.羟基异戊酰肉碱(C5-OH)增高,气相色谱质谱显示尿3-甲基巴豆酰甘氨酸、3-羟基异戊酸、甲基枸橼酸等排出增多,生物索酶活性测定可鉴别病凶.通过新生儿筛查、早期诊治,可降低病死率及后遗症的发生率.目前已报道的生物素酶基因突变113种,常见G98:d7i3、R538C、Q456H等.全羧化酶合成酶基因突变30种,常见R508W、V550M等,L237P和780delG为日本患者的热点突变.基因型与酶活性有关,但与临床表型无明确的相关性.生物素10～40mmg/d治疗后数日至2周临床症状明显改善,预后良好.     

线粒体乙酰乙酰辅酶A硫解酶缺乏症一家系报告并文献复习

目的探讨线粒体乙酰乙酰辅酶A硫解酶缺乏症(简称T2缺乏症)的诊断及预后。方法回顾性分析一家系中3例T2缺乏症患儿的临床资料,并复习相关文献。结果例1和例2为先证者,男孩,同卵双胞胎,因发热、呕吐、气促入院,血气分析均显示严重的代谢性酸中毒,尿气相色谱质谱均显示3-羟基丁酸、2-甲基-3-羟基丁酸、甲基巴豆酰甘氨酸-1、3-甲基巴豆酰甘氨酸-1明显增高,二羧酸轻微升高;血串联质谱仪分析结果均显示,C5∶1、C5-OH、C4-OH升高。例3,为例1和例2同胞姐姐,5月龄时因严重代谢性酸中毒住院治疗。3例患儿行ACAT1基因检测均为复合杂合突变,c.622 CT(p R208X)和c.653 CT(p S218F)。结论对于以酸中毒为突出表现的患儿,需警惕T2缺乏症,及时行尿气相色谱质谱和血串联质谱分析,以早期诊断和治疗。     

Partial biotinidase deficiency: clinical and biochemical features

Neonatal screening for profound biotinidase deficiency (less than 10% of the mean normal activity level) has identified a group of children with partial biotinidase deficiency (10% to 30% of mean normal activity). Because partial biotinidase deficiency may result in clinical consequences that may be prevented by treatment with biotin, we evaluated such individuals and their family members (1) to determine whether partial biotinidase deficiency is associated with symptoms and (2) to determine the inheritance pattern. We quantified serum biotinidase activity levels and obtained medical histories of probands, their parents and siblings, and additional family members. All children with partial deficiency were healthy at the time of diagnosis. One child, who was not initially treated with biotin, later developed hypotonia, hair loss, and skin rash, which resolved with biotin therapy. Four adults and three children with partial biotinidase deficiency were identified among family members of infants identified by neonatal screening. All these individuals were healthy, although one sibling had elevated urinary lactate excretion. A fifth adult with partial deficiency, found among clinically normal adult volunteers, later showed minor symptoms that resolved after biotin therapy. Like children with profound biotinidase deficiency, children with partial biotinidase deficiency are symptoms free at birth. However, the subsequent occurrence of symptoms of profound biotinidase deficiency in some persons with partial deficiency suggests that biotin therapy for this condition may be warranted.     

Relationship between kinetic properties of mutant enzyme and biochemical and clinical responsiveness to biotin in holocarboxylase synthetase deficiency

Holocarboxylase synthetase (HCS) deficiency is a metabolic disorder that causes a biotin-responsive multiple carboxylase deficiency. We analyzed the kinetic properties of seven mutant HCS proteins. Two of these enzymes harbored mutations within the putative biotin-binding region of HCS and showed elevated Km values for biotin compared with that of the wild-type form (Km mutant; Gly581Ser: 45 times, delThr610: 3 times). The remaining five mutations (Arg183Pro, Leu216Arg, Leu237Pro, Val333Glu, and Val363Asp) were located outside the biotin-binding region. The enzymes containing these mutations showed normal or low Km values for biotin (non-Km mutant). Symptoms of patients who have the non-Km, mutants, as well as those of patients who have the Km, mutants, responded to biotin therapy. This is probably because the Km value for biotin of normal HCS is higher than the physiologic concentration of biotin in human cells. The Vmax values of all mutant HCS proteins were considerably decreased, but to a variable degree. The responsiveness to biotin supplementation of propionyl-CoA carboxylase activity in cultured cells bearing the mutations correlated well with the degree of reduction in the Vmax of HCS. Patients who have mutant HCS proteins with lower Vmax showed poorer clinical and biochemical responses to biotin therapy. These observations suggest that the reduction of Vmax is an essential factor for pathophysiology and prognosis of HCS deficiency under treatment with large amounts of biotin. The determination of HCS genotype can be valuable for characterizing the clinical phenotype in HCS deficient patients.     

The first reported HLCS gene mutation causing holocarboxylase synthetase deficiency in a Vietnamese patient

Background

Holocarboxylase synthetase deficiency is an inborn error of biotin metabolism leading to multiple carboxylase deficiency which is often biotin responsive. This disease is believed to be relatively common among the Asian population.

Methods

A 6-year-old Vietnamese boy presented with recurrent episodes of severe metabolic acidosis precipitated by intercurrent illnesses. An extensive skin rash was present since the onset of his illness. Multiple carboxylase deficiency was considered a likely diagnosis based on the history and the characteristic skin rash.

Results

This diagnosis was later confirmed by urine organic acid and molecular genetic studies. Urine organic acid showed characteristic excretion of glycine conjugates. Serum biotinidase activity was normal. Sequencing of the holocarboxylase synthetase gene revealed the patient being homozygous for a common mutation R508W. The patient showed a dramatic response to biotin within days of its administration.

Conclusion

This case illustrates a potential highly treatable inborn error of metabolism that can be recognized on clinical grounds and its favorable response to biotin treatment.     

Mutations causing profound biotinidase deficiency in children ascertained by newborn screening in the United States occur at different frequencies than in symptomatic children.

Biotinidase deficiency is an autosomal recessive disorder of biotin metabolism that can lead to varying degrees of neurologic and cutaneous symptoms when untreated. Because this disorder meets the criteria for newborn screening, many states and countries perform this testing. Because newborn screening should result in complete ascertainment of mutations causing profound biotinidase deficiency (less than 10% of mean normal serum activity), we compared the mutations in a group of 59 children with profound biotinidase deficiency who were identified by newborn screening in the United States with 33 children ascertained by exhibiting symptoms. Of the 40 total mutations identified among the two populations, four mutations comprise 59% of the disease alleles studied. Two of these mutations occur in both populations, but in the symptomatic group at a significantly greater frequency. The other two common mutations occur only in the newborn screening group. Because two common mutations do not occur in the symptomatic population, it is possible that individuals with these mutations either develop mild or no symptoms if left untreated. However, inasmuch as biotin treatment is inexpensive and innocuous, it is still recommended that all children with profound biotinidase deficiency be treated.     

Biotinidase deficiency—A treatable entity

Biotinidase deficiency is a well recognised treatable cause of a wide spectrum of progressive neurological symptoms. Recent reports have stressed the need to screen children with early onset of seizures, encephalopathy, neurodevelopmental delay, skin rash and alopecia. Enzyme estimation remains the conclusive test. We present a patient with biotinidase deficiency suspected on the above clinical grounds and diagnosed on the basis of metabolic acidosis, raised blood lactate, ketonuria and positive dinitrophenylhydrazine (DNPH) test and confirmed on urinary organic acid profile. Supplementation with biotin resulted in marked clinical improvement and normalisation of metabolic parameters. Thus the clinician should be alert to simple clinical pointers which aid in early diagnosis of these disorders.     

Biochemical and immunologic characterization of serum biotinidase in partial biotinidase deficiency.

Newborn screening for biotinidase deficiency has identified children with profound biotinidase deficiency (less than 10% of mean normal activity) and about an equal number of children with partial biotinidase deficiency (10 to 30% of mean normal activity). Partial biotinidase deficiency was initially considered a variant without clinical consequences until one child, during an episode of gastroenteritis, developed symptoms of biotinidase deficiency that resolved with biotin therapy. Biochemical and immunologic characterization of biotinidase was performed in sera from 23 children with partial biotinidase deficiency from 19 families and 18 of their parents. As expected, all patients had cross-reacting material in their serum. Patients with partial biotinidase deficiency can be classified into six distinct biochemical phenotypes on the basis of the number of isoforms and the distribution frequency of the isoforms. Kinetic studies were performed on samples from 17 of the patients and were found to be normal in all cases. The patient with partial deficiency who became symptomatic has an isoform profile that is not different from 10 other asymptomatic, partially deficient children. The parents had normal isoform patterns. The isoform patterns observed in the patients with partial biotinidase deficiency were not different from those of the profoundly deficient patients who had cross-reacting material.     

远端肾小管酸中毒患儿基因型及临床表型的相关性分析

目的对确诊的6例原发性远端肾小管酸中毒(dRTA)的病例行基因型及临床表型的相关性分析。方法对2017年11月至2019年8月确诊于华中科技大学同济医学院附属武汉儿童医院的6例dRTA患儿行病史资料采集及相关辅助检查,评估其生长发育情况,留取静脉全血进行Trio全外显子高通量测序,经全谱遗传病精准诊断云平台系统分析筛选和数据分析,对可疑突变进行Sanger测序验证,后应用蛋白预测软件进行蛋白功能预测。结果6例患儿的临床症状、体征和辅助检查均符合dRTA的诊断,均表现为生长发育落后,1例患儿出现X型腿,1例患儿出现骨质疏松。辅助检查均提示低钾血症、代谢性酸中毒、碱性尿,3例患儿出现肾脏钙质沉着,2例患儿出现肾脏结石,所有患儿的父母亲均无临床表型。1例患儿为SLC4A1基因纯合突变[c.2102(exon17)G>A,p.G701D],为既往报道的常染色体隐性遗传高频突变位点,该患儿同时合并dRTA及溶血性贫血;3例为SLC4A1基因杂合突变,均为De novo突变[c.1766(exon14)G>A,p.R589H,c.1765(exon14)C>T,p.R589C],为既往报道的常染色体显性遗传高频突变位点,确诊年龄与肾脏影像学异常存在相关性。1例为ATP6V1B1基因复合杂合突变[c.806(exon9)C>T,p.P269L;c.1153(exon12)C>A,p.P385T],均为未见文献报道的新突变位点。1例为ATP6V0A4基因纯合无义突变[c.1899C>A,p.Y633X,208],为未见文献报道的新突变位点。结论SLC4A1、ATP6V1B1、ATP6V0A4是目前已明确的dRTA的主要致病基因,其突变特点及遗传方式与临床表型相关。基因检测可以对可疑的dRTA患者行早期分子诊断,有助于临床表型的筛查及个体化治疗。