苯丙酮尿症患者32例家系基因突变研究北大核心CSCD

目的：检测苯丙酮尿症（PKU）患儿及其父母苯丙氨酸羟化酶（PAH）基因突变谱,并探讨 PAH 基因突变与临床严重程度的相关性,为本地区 PKU 患儿的早期诊断及遗传咨询提供基础数据。方法使用高通量测序技术对来自江苏省无锡和宿迁的32例 PKU 患儿及其父母的 PAH 基因13个外显子及其附近内含子区域进行测序分析。结果32例 PKU 共检测出61个突变位点,33种突变基因,突变检出率为95.31％（61/64个）。本地区 PKU 患儿常见致病突变位点为 c.721C ﹥ T、c.1068C ﹥ A、c.611A ﹥ G、c.1197A ﹥ T、c.728G ﹥ A、c.331C ﹥ T 和 c.442-1G ﹥ A,其突变频率均在5％以上。首次报道1个新的突变基因位点 c.699C ﹥ G 和3个汉族人口中新的突变基因位点 c.265C ﹥ T、c.722G ﹥ A 和 c.1194A ﹥ G。Guldberg AV 系统分析显示38.0％（8/21例）的 PKU 患者基因型与实际生化表型相一致,其中预测表型为中重度的与实际生化表型的一致率为92.3％（12/13例）,轻度的与实际生化表型的一致率为50.0％（4/8例）。结论江苏地区 PKU 患儿的 PAH 基因突变集中在外显子7上,其中频率最高的基因位点是 c.721C ﹥ T,并首次发现1个新的基因突变位点 c.699C ﹥ G;PKU 患者基因型与生化表型之间有一定的相关性。     

青海地区苯丙酮尿症患者苯丙氨酸羟化酶基因突变分析

目的 明确青海地区苯丙酮尿症患者苯丙氨酸羟化酶(PAH)基因的突变特征,为该地区苯丙酮尿症(PKU)的产前诊断和遗传咨询提供理论依据。方法 选取2006年1月至2012年12月经新生儿疾病筛查及门诊遗传咨询发现并确诊的49例青海地区PKU患儿为研究对象,应用PCR产物直接测序法对49例PKU患儿及其父母的PAH基因启动子、第1~13外显子及其旁侧内含子区域进行基因突变分析。结果 在98个PAH等位基因中检测出30种、共计80个不同的突变基因,总检出率为82%(80/98),主要包括19种错义突变(63%)、5种无义突变(17%)、3种剪切位点突变(10%)和3种缺失突变(10%),大部分突变集中在第3、6、7、11外显子及第4内含子区域,常见的4种突变是p.R243Q(19%)、IVS4-1G>A(9%)、p.Y356X(7%)和p.EX6-96A>G(5%);p.N93fsX5(c.279-282delCATC)、p.G171E(c.512G>A)突变是国际上未见报道的新的PAH基因突变,p.H64fsX9(c.190delC)突变为国内第2次报道。青海地区PAH基因的突变构成有一部分与北方各省份相似,与中国南方部分省区及日本、欧洲等国家差异显著。结论 青海地区表现出多民族聚居地区PAH基因突变特有的多样性和复杂性。     

信息动态

目的 利用MassArray基因分型技术对苯丙酮尿症(PKU)患儿家系致病基因进行检测,探讨该技术应用于孕前、产前和新生儿PKU预测与诊断的可行性.方法 采用新生儿遗传代谢病常规检测与串联质谱相结合的方式,在烟台地区筛查到2例PKU患儿,利用MassArray技术对PKU患儿及亲属苯丙氨酸羟化酶(PAH)基因突变位点进行检测,寻找可能的致病突变位点,并采用下一代测序技术对MassArray基因检测结果进行验证.结果 在2个家系样本中发现4种基因突变.突变位点是c.158G＞A,c.1197A ＞T,c.728G＞A,C.442-1G ＞A.结论 MassArray基因分型技术可快速对PKU基因突变位点进行检测,随着检测突变位点的增加,可为PKU的预测与基因确诊提供有效的临床参考依据.     

苯丙酮尿症并癫(癎)患儿脑髓鞘病变的意义

目的 观察苯丙酮尿症(PKU)并癫(癎)患儿腩髓鞘延迟的情况,探讨PKU对神经系统的损伤.方法 PKU患儿42例,年龄3～72个月.经高压液相色谱法定量测定其血苯丙氨酸(PHE)水平>1.2 mmol/L,确诊为经典型PKU.其中21例根据脑电图及临床表现诊断为癫(癎)(癫(癎)组),余21例PKU患儿未并癫(癎)(对照组).42例患儿治疗前均行MRI检查,确诊后开始行低PHE饮食治疗.脑髓鞘发育评估采用Staudt评估标准.观察2组患儿10个区域(小脑、桥脑、中脑、内囊后肢、内囊前肢、枕叶、额叶、顶叶、颞叶、胼胝体)脑髓鞘延迟情况.结果 癫(癎)组患儿头颅MRI显示10个脑区脑髓鞘均有不同程度的延迟存在,其胼胝体延迟发生率为80.9%,10个脑区平均髓鞘延迟发生率为44.8%;对照组胼胝体髓鞘延迟发牛率为52.4%,10个脑区平均延迟发生率为30.9%,2组脑髓鞘延迟发生率比较有明显差异(P<0.01).脑电图轻度异常与中重度异常患儿治疗前后髓鞘延迟发生率比较有显著差异(P<0.01).结论 并癫(癎)的晚治PKU患者脑髓鞘延迟病变发牛率明显高于未并癫(癎)患者,低PHE饮食治疗在一定程度上可影响癫(癎)症状的改善,脑髓鞘发育延迟可能是导致PKU患者癫(癎)发作的主要原因之一.     

反复抽搐、肺部感染并发育落后

患儿,女,4月龄,新生儿期出现抽搐,初起为局灶性运动发作,4月龄时转变为痉挛和强直-痉挛发作,并有发育落后及反复肺部感染。脑电图示高度失律,头颅磁共振、脑脊液检查正常,血氨、血乳酸、血液氨基酸和酰基肉碱谱分析、尿液有机酸分析正常,基因检测发现GNAO1 c.607G>A （p.G203R）新生杂合错义突变,确诊为GNAO1相关早发性癫癎脑病（EIEE17型）。改用托吡酯和氨己烯酸治疗,癫癎发作控制,但精神运动发育无进步,肺部感染反复,12月龄时因重症肺炎死亡。对于不明原因早发性癫癎脑病患儿需警惕GNAO1基因突变,尽早进行遗传学检测,并注意可能合并反复肺部感染。     

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。     

3 例Menkes病患儿的临床与ATP7A基因分析及1例产前诊断研究

Menkes 病是一种罕见的X 连锁隐性遗传病,由于ATP7A 基因突变导致铜吸收障碍,铜相关酶功能缺陷,引起多系统功能障碍。该文拟通过对3 例Menkes 病患儿的临床经过和ATP7A 基因突变分析对该症进行研究,并对1 例再孕母亲进行产前诊断研究。3 例男婴于8~9 个月时来院就诊,均为婴儿期起病,主要表现为抽搐和智力运动落后,抗癫癎治疗无效,面色苍白,毛发稀疏、卷曲,小头,MRI 扫描显示脑萎缩、白质异常、基底节损害和脑血管形态改变,血浆铜蓝蛋白均显著降低,分别为70.2、73.5、81.0 mg/L（参考值210~530 mg/L）,符合经典型Menkes 病临床表型。例1 和2 的ATP7A 基因存在c.3914A>G（p. D1305G）突变,例3 为c.3265G>T（p.G1089X）突变,均为新生突变。c.3914A>G（p. D1305G）为已知突变,c.3265G>T（p.G1089X）为新突变,均为我国首次报道。例1 患儿的母亲再孕,于妊娠20 周时抽取羊水细胞,通过胎儿ATP7A 基因突变分析,进行产前诊断。羊水细胞ATP7A 基因未见c.3914A>G,提示胎儿未患与先证者相同的疾病。胎儿出生后发育正常。     

误诊为脑性瘫痪的苯丙酮尿症

目的分析苯丙酮尿症(PKU)患儿的临床误诊情况。方法对2003年1月~2006年10月本院门诊首诊为脑性瘫痪的72例PKU患儿进行回顾性分析,包括家族史、现病史、体格检查、脑电图和CT摄片、末梢血苯丙氨酸(phe)水平。结果临床表现为癫17例,运动障碍19例,语言障碍64例,湿疹25例,情绪暴躁43例,尿液、汗液有明显异味70例。采用Guthrie's法测定患儿血phe水平,并采用四氢生物喋呤负荷实验对72例患儿进行诊断,其中71例确诊为经典型PKU,1例确诊为四氢生物喋呤缺乏症。结论PKU引起的智能落后较常见,临床上易被忽视,导致漏诊和误诊。     

宁夏地区苯丙酮尿症患儿苯丙氨酸羟化酶基因外显子6突变研究

目的 探讨宁夏地区苯丙酮尿症(PKU)患儿苯丙氨酸羟化酶(PAH)基因外显子6突变类型及频率,为该地区PKU的基因诊断和产前诊断提供依据.方法 应用聚合酶联反应(PCR)产物直接测序方法,对宁夏73例经典型PKU患儿[PKU患儿均为宁夏新生儿疾病筛查中心2010年1月至2013年6月确诊,病例分布于宁夏22县(市、区);年龄15 d～13岁;男38例,女35例;回族39例,汉族34例]和100例(回族50例,汉族50例)健康新生儿的PAH基因外显子6及其旁侧内含子区域进行序列分析.结果 共检测出6种基因突变型别,分别是EX6-96A＞ G(6.85％)、Q232X(2.74％)、D222G(1.37％)、V2301(1.37％)、R176X(0.68％)和N223I(0.68％),基因外显子6突变检出率为13.70％,包括3种突变型别,分别是错义突变3种(50.0％)、无义突变2种(33.3％)和剪切位点突变1种(16.7％);查阅国内外文献,其中EX6-96A＞G、Q232X和R176X国内早有报道,D222G、V2301为国内首次报道的PAH突变,N223I为国际上尚未见报道的新PAH突变.结论 明确了宁夏地区PAH基因外显子6突变类型及频率,丰富了该地区PKU基因研究,为开展PKU的基因诊断提供依据.     

苯丙氨酸羟化酶缺乏症患儿基因型和表型关系及其临床应用的研究

目的构建苯丙氨酸羟化酶(PAH)缺乏症患儿的PAH基因变异谱,研究基因型和表型的关系。方法回顾分析76例经新生儿筛查确诊的PAH缺乏症患儿的PAH基因变异位点,建立基因型-表型预测模型。对等位基因进行赋值,设定变异位点特定值(AV),并计算AV评分之和,进而预测临床表型。结果应用第二代高通量测序技术和多重连接酶探针依赖扩增检测(MLPA)技术,在76例新生儿152个PAH等位基因中共检测出146个变异位点,频率为96.1%。70例新生儿检测出2个变异等位基因,其中3例纯合变异,67例复合杂合变异;另外6例检测出1个变异等位基因。共检测出变异类型45种,变异频率较高的位点为c.728GA(26/146,17.8%)、c.158GA(13/146,8.9%)、c.1068CA(11/146,7.5%)、c.721CT(10/146,6.8%),c.1238GC(8/146,5.5%)、c.331CT(8/146,5.5%)、c.1301CA(7/146,4.8%)。其中c.95AG位点未曾被BIOPKU数据库报道。患儿治疗前血苯丙氨酸(Phe)浓度与AV评分之和呈显著负相关(r=-0.83,P0.001)。随访发现2例轻度高苯丙氨酸血症患儿血Phe浓度120 μmol/L者无需治疗。结论构建常见PAH基因变异谱,验证了PAH基因突变和表型的相关性,有助于PAH确诊及分型、早期判断预后以及遗传咨询。     

A Chinese family with phenylketonuria and maternal phenylketonuria detected by family screening

A 16-year-old boy with classical phenylketonuria (PKU) and mild mental retardation (IQ 69) was detected by the screening of mentally retarded school children in Taiwan with Guthrie's bacterial inhibition assay. The follow-up family study showed that one of his married elder sisters suffered from borderline mental retardation (IQ 75) and was also diagnozed as a classical case of PKU. She had borne one boy and one girl, both suffering from mild mental retardation, microcephaly, delay in linguistic development and severe growth retardation. This is the first known Chinese family with maternal PKU. To prevent future mental retardation caused by maternal PKU, the simultaneous establishment of a register system with a neonatal screening programe, is indicated for the follow-up of PKU girls, screening of the whole family of newly discovered PKU cases, and to exclude unrecognized maternal PKU in women who have given birth to a microcephalic child.Abbreviations PKU phenylketonuria - WAIS Wechsler adult intelligence scale - CCDI Chinese children development inventory     

Long-term enzymatic and phenotypic correction in the phenylketonuria mouse model by adeno-associated virus vector-mediated gene transfer

Phenylketonuria (PKU) is an autosomal recessive metabolic disorder caused by a deficiency of phenylalanine hydroxylase (PAH). The accumulation of phenylalanine leads to severe mental and psychomotor retardation, and hypopigmentation of skin and hair. Low-phenylalanine diet therapy can prevent irreversible damage if instituted from birth. However, poor compliance with the strict lifelong dietary therapy leads to various neurologic and behavioral problems. To develop a safe and promising gene therapy method for PKU, we investigated whether a recombinant adeno-associated virus could be used as a PAH gene transfer vector to reduce the excessive phenylalanine level in the PKU mouse model. A recombinant adeno-associated virus vector encoding the human PAH gene (rAAV-hPAH), driven by EF1-alpha promoter, was infused into PAH-deficient mice, Pah(enu2), via the hepatic portal vein. Two weeks after injection, the plasma phenylalanine level dramatically decreased to 360 microM in male PKU mice, accompanied by the coat color changing to black. The mean plasma phenylalanine level of untreated PKU mice was 1800 microM. The PAH enzyme activities of treated mice increased to 10-17% of wild-type mice. No signs of liver toxicity were observed after gene transfer. The biochemical and phenotypic corrections were sustained for up to 25 wk (25-wk detection period). In contrast, the treatment was less effective in female PKU mice. These results indicate that recombinant adeno-associated virus vector-mediated gene therapy can be a useful therapeutic candidate for patients with PKU. Further studies are needed to clarify the differences in PKU pathogenesis in males and females, and to explore alternative administration routes besides hepatic portal vein injection.     

Maternal phenylketonuria: comparison of two treated full term pregnancies

This case report documents the fetal outcome of two full term pregnancies in a patient with phenylketonuria (PKU). She was treated with a low phenylalanine diet preceeding and during both pregnancies. During her first full term pregnancy she was not able to maintain the rigid diet, and this pregnancy resulted in the delivery of a growth-retarded, microcephalic boy. In her second pregnancy the patient maintained the diet until her delivery at full term. Maternal blood phenylalanine levels remained with two exceptions below 600 mol/l throughout pregnancy and an infant of normal weight and head circumference was born.Abbreviations PKU phenylketonuria - BPD biparietal diameter     

Tay or IBIDS syndrome. A case with growth and mental retardation, congenital ichthyosis and brittle hair.

A new, Swedish case with Tay or IBIDS syndrome is presented. The boy had growth and mental retardation, congenital ichthyosis and brittle hair. He was the only child in an uncle-niece marriage. The boy suffered recurrent infections and died at the age of 3 years from pneumonia. Clinical data on 15 cases are presented from a study of the literature.     

Tay or IBIDS Syndrome: A Case with Growth and Mental Retardation, Congenital Ichthyosis and Brittle Hair

ABSTRACT. A new, Swedish case with Tay or IBIDS syndrome is presented. The boy had growth and mental retardation, congenital ichthyosis and brittle hair. He was the only child in an uncle–niece marriage. The boy suffered recurrent infections and died at the age of 3 years from pneumonia. Clinical data on 15 cases are presented from a study of the literature.     

Sudden onset of refusal to eat on waking after a nightmare in a 6-year-old girl

CASE: Bridgette is a 6-year-old girl, who presented with sudden onset of refusal to eat or drink. The only precipitating event was a nightmare the previous night. She described a dream in which her mother and maternal aunt, dressed as witches, and father and maternal uncle, appearing as bats, wanted to kill her by making her eat and drink from a cauldron. Bridgette stated, "I can't eat anymore, I'm afraid of dying." Bridgette's eating pattern and behavior were described as previously normal. Motor, social, and language milestones were also normal. Her parents reported that she occasionally refused nonpreferred foods, and they believed that her food intake had decreased at age 4 years. She was a full-term infant without perinatal problems and breast fed until 8 months. Her medical history was significant for strabismus surgery, before 6 months. Her mental health history revealed mildly depressed mood and irritability related to teasing at school after her strabismus surgery. Her parents described her as "always looking for attention." Her teachers reported that she had normal intelligence and described her behavior as shy, slightly withdrawn, and distrustful. Social history revealed an only child of married parents without marital or work-related problems. Bridgette went to her maternal grandmother's home after school and during school holidays.Her parents pleaded with her to eat, but she refused. She was evaluated at urgent care where her physical examination was described as normal. Her body mass index was above the 97th percentile (3 SD above the mean). The parents were described as fearful and despairing. Laboratory tests included a complete blood count with differential, an electroencephalogram, and a computed tomography scan, all of which were normal. Intravenous fluids were administered on the day of presentation and the following day. She continued to refuse to eat or drink, and after 2 days, she was hospitalized for nasogastric tube feeding.     

The international collaborative study of maternal phenylketonuria: status report 1994

Neonatal screening for phenylketonuria (PKU) has created a problem as females with PKU are reaching child-bearing age. Surveys have revealed that maternal phenylalanine blood concentrations greater than 1200 μmol/l are associated with fetal microcephaly, congenital heart defects and intrauterine growth retardation. It is estimated that as many as 3000 hyperphenylalaninemic females may be at risk of producing these fetal abnormalities. To examine this problem, the international maternal PKU collaborative study was developed to evaluate the efficacy of a phenylalanine-restricted diet in reducing fetal morbidity. Preliminary findings have indicated that phenylalanine restriction should begin before conception for females with PKU planning a pregnancy. Dietary control should maintain maternal blood phenylalanine levels between 120 and 360 μmol/l and should provide adequate energy, protein, vitamin and mineral intake. Pregnant hyperphenylalaninemic females who achieved metabolic control after conception or by the 10th week of pregnancy had a better offspring outcome than anticipated. The results of 402 pregnancies are reviewed.     

转录辅助调节因子HCFC1突变致罕见X连锁甲基丙二酸尿症CblX型一家系报告

目的探讨X连锁甲基丙二酸尿症CblX家系的临床及基因特点。方法回顾性分析1例经血液及尿液分析发现甲基丙二酸尿症,并采用靶向捕获二代测序进行HCFC1基因分析诊断的X连锁甲基丙二酸尿症患儿的临床资料。结果患儿,男,于2月龄时出现抽搐,智力运动障碍,5月龄时表现癫痫、重度发育落后,尿甲基丙二酸、血液丙酰肉碱增高,血浆总同型半胱氨酸增高,符合甲基丙二酸尿症合并同型半胱氨酸血症。甲基丙二酸尿症相关常染色体基因分析未见突变,X染色体转录辅助调节因子HCFC1第3外显子存在c.344C??T(p.Ala115Val)半合子突变,证实为CblX型甲基丙二酸尿症。患儿父母健康,曾有一子生后重度智力、运动障碍,合并难治性癫痫,于6月龄夭折。患儿母亲携带相同的突变,尿液可检出少量甲基丙二酸,血浆同型半胱氨酸轻度增高。患儿父亲未携带突变。结论以新一代测序技术首次确诊我国1例X连锁CblX型甲基丙二酸尿症家系。     

Embryofetopathy caused by postnatally detected maternal phenylketonuria

A case of a now 10-month-old female infant is reported, who presented at birth with microcephalus, growth retardation, dystrophia, facial dysplasia and cardiac defect. Etiologically a classical phenylketonuria of the mother with very high levels of serum phenylalanine (51 and 41 mg/dl, respectively), which was not known until then, was diagnosed already after her confinement. The mother, aged 26, originates from Roumania. She had never been treated by any phenylalanine-limited diet. Psychological testing revealed a severely reduced intelligence (IQ = 63). The child, having normal levels of serum phenylalanine, presented with mild statomotor retardation at the age of ten months. Even in countries with a general neonatal screening program, a hitherto undiagnosed maternal phenylketonuria has to be considered within the differential diagnosis of a dystrophic microcephalic newborn, beside more common causes like the fetal alcohol syndrome.     

West syndrome associated with Down syndrome: Case report and literature review

West syndrome is the most frequent cause of epilepsy in Down syndrome. West syndrome is often associated with poor long-term prognosis in most of children. We report a girl with West syndrome associated with Down syndrome which occurred at 8 months of age for repetitive flexor spasms and electroencephalography (EEG) showed hypsarrhythmia. She had Down syndrome facies, microcephaly, psychomotor development delay and axial hypotonia. Computed tomography of the brain was normal. Her karyotype was 47, XX, +21. Phenobarbital therapy was immediately effective with good clinical control of seizures, while the EEG monitored after one month was unchanged. At 2 years of age, the patient had hypertonic status epilepticus following a lung infection. The EEG showed a persistence of hypsarrhythmia. Sodium valproate and hydrocortisone therapy was effective with good seizure control but her psychomotor development was severely impaired. After a follow-up of 7 years, the patient presents growth retardation, microcephaly, severe psychomotor development delay, generalized hypotonia and tetraparesis. Knowledge of West syndrome in Down syndrome allows the early detection and prompt management of this neurological complication in order to optimize psychomotor development and improve the quality of life of these children.