|关键词||葡萄糖转运子Ⅰ缺乏综合征 SLC2A1基因突变 临床特点 生酮饮食|
|其他题名||Clinical and Genetic Characteristics of Glucose Transporter Type 1 Deficiency Syndrome and Outcomes|
目的 对我国疑诊葡萄糖转运子I缺乏综合征（Glucose Transporter type 1 deficiency syndrome, GLUT1-DS）的患儿进行SLC2A1 (solute carrier family 2 member 1)基因分析，总结我国GLUT1-DS疾病的临床特点及基因型分布，对患儿进行随访，了解其预后。 方法 1、自2008年11月至2015年8月于北京大学第一医院小儿神经科诊治的疑似GLUT1-DS患儿31例，收集其病史资料，行脑脊液（cerebrospinal fluid, CSF)常规、生化、乳酸检查，及全血生化、血及尿氨基酸与有机酸筛查、脑电图（electroencephalogram, EEG)、头颅核磁共振成像（magnetic resonance imaging, MRI）等检查。 2、采集患儿及其父母外周血，应用聚合酶链式反应（polymerase chain reaction, PCR）、测序及多重连接探针扩增技术（multiplex ligation-dependent probe amplification, MLPA）对SLC2A1基因进行突变分析。 3、 总结临床诊断、疑诊、排除GLUT1-DS的患儿的临床、脑脊液、基因突变特点。 4、对临床诊断为GLUT1-DS的18例患儿进行随访，对其临床资料、基因突变、基因型与表型的关系、治疗与转归进行综合分析。 结果 1、 疑诊GLUT1-DS患儿31例，经临床、脑脊液、基因突变分析，最终临床诊断为GLUT1-DS患儿18例，疑诊1例，排除GLUT1-DS患儿12例。 2、 临床诊断为GLUT1-DS的18例患儿的基因突变特点：（1）诊断：15例患儿基因型分析阳性。例1外显子1-10大片段缺失，例2外显子1-2大片段缺失。6例错义突变分别为例3 c.1199G>A(p.R400H)、例4 c.1372C>T(p.R458W)、例10 c.997C>T(p.R333W)、例11 c.1148C>A(p.P383H)、例13 c.1198C>T(p.R400C) 、例14 c.985G>A(p.E329K)。6例截断突变分别为例5单个核苷酸插入突变 c.332dupG(p.G111fs)、例8点缺失突变c.599delA(p.Q200fs)、例12点缺失突变 c.761delA(E254fs) ，例15 起始密码子改变c. 2T>C (p. Met1?) 和例9和例17 的无义突变c.988C>T（p.R330X）。1例剪切位点突变为c.680-11G>A(p.227_228insPPV，例6、例7患儿的基因突变均为阴性，例18未进行基因分析。 3、 临床诊断为GLUT1-DS的18例患儿的临床特点：（1）7例患儿为经典型，以早发婴儿难治性癫痫、运动障碍、发育落后、获得性小头畸形为主要表现；11例非经典型患儿以发作性共济失调、无力、肌张力障碍或精神行为异常为主要表现。（2）脑脊液检查：除1例患儿未进行脑脊液检查外，17例患儿每人至少一次脑脊液糖绝对值小于2.5mmol/L，脑脊液糖平均值范围为1.17-2.25mmol/L，所有例次的平均值为1.82mmol/L，脑脊液糖与血糖比值范围为0.23-0.50，平均值为0.37。（3）EEG：10例患儿脑电图异常，发作间期呈弥漫性或局灶性痫样放电，其中2例背景慢波增多，5例患儿监测到惊厥发作。1例患儿脑电图监测到进食半小时后发作间期痫样放电明显减少。（4）头颅MRI：16例患儿进行了头颅MRI检查，10例正常，3例脑白质发育落后，2例轻度脑萎缩，1例脑室增宽。（5）治疗及预后随访：12例进行生酮饮食的患儿，9例生酮效果好，发作性症状控制、发育改善；1例癫痫发作无减少、发作性无力改善，1例病人生酮1月后癫痫发作无减少、因腹泻、纳差夭折，1例生酮饮食后发作增多。7例未行生酮饮食治疗的患儿中6例发作性运动障碍、精神行为异常随年龄增长有减轻趋势，1例患儿仍有频繁发作。 4、 经典型患儿脑脊液糖低于非经典型，但二者无统计学差异。基因突变为错义突变和剪切位点突变的患儿脑脊液糖高于截断突变的患儿，但二者无统计学差异。经典型和非经典型的基因型均有错义突变、截断突变，二者无统计学差异。2例大片段缺失患儿均为经典型，脑脊液糖较其他突变类型低。 5、 疑诊GLUT1-DS的1例患儿以发作性意识减低为主要表现，伴发作性无力，多次脑脊液糖轻度降低或正常，SLC2A1基因突变为c.1213G>A(p.A405T)，患儿父亲相同突变，为无症状携带者，患儿母亲基因分析正常。 6、 排除GLUT1-DS的12例患儿中8例主要表现为难治性癫痫，3例表现为癫痫合并发作性运动障碍，1例表现为发作性运动障碍，其发作与饥饿、劳累、运动等无关。11例行脑脊液检查，其中6例脑脊液糖正常，5例脑脊液糖轻度下降，脑脊液糖与血糖比值轻度降低或正常，所有患儿的基因分析均为阴性。 结论 1、 GLUT1-DS的患儿临床表现多样，对于婴儿早发性难治性癫痫合并发育落后，发作性运动障碍、肢体无力、共济失调的患儿，尤其是饥饿、疲劳、运动时可诱发或加重者，要高度怀疑GLUT1-DS的可能性。 2、 脑脊液糖、脑脊液糖与血糖比值降低是本病重要的临床诊断依据。脑脊液检查对疾病的早期诊断至关重要。临床症状符合GLUT1-DS，但脑脊液糖轻度降低或正常的患儿不能排除GLUT1-DS的诊断，需要进行SLC2A1基因突变分析。 3、 SLC2A1基因突变是GLUT1-DS的确诊依据，但部分GLUT1-DS患儿基因突变阴性。 4、 脑脊液糖与临床表型未发现显著相关，需扩大样本进一步研究。 5、 基因突变类型与脑脊液糖水平、临床表型未发现显著相关，大片段缺失可能与临床严重表型有关，需扩大样本进一步研究。 6、 GLUT1-DS是可治性的神经系统疾病，生酮饮食可改善患儿的预后。部分患儿生酮疗效欠佳，提示有可能存在能量缺乏以外的致病机制。
Objective To detect the pathogenic SLC2A1 gene mutations and explore the mutation spectrum and clinical acteristics of Chinese patients with glucose transporter type 1 deficiency syndrome (GLUT1-DS), and the outcomes of patients with and without ketogenic diet. Methods 1． Retrospectively analysis the detailed information of the clinical manifestations, the biochemistry and cell count of cerebrospinal fluid (CSF), blood biochemistry, blood and urine amino acid and organic acid, electroencephalogram (EEG) and magnetic resonance imaging (MRI) of 31 cases with suspected GLUT1–DS. 2． SLC2A1 gene mutation analysis were performed on 30 cases with suspected GLUT1–DS by polymerase chain reaction (PCR), sequencing and multiplex ligation dependent probe amplification (MLPA). The clinical acteristic of the patients with SLC2A1 gene mutation and the outcomes of patients with and without ketogenic diet treatment were studied. 3． The clinical acteristic, cerebrospinal fluid test and genetic analysis of the confirmed, suspected and excluded patients with GLUT1–DS were studied. 4． The clinical acteristic, cerebrospinal fluid test, genetic analysis and outcomes of the confirmed GLUT1–DS patients were studied. The relationship between phenotype, CSF glucose level and mutation type was analyzed. Results 1． According to the clinical manifestation, the glucose level of CSF and the SLC2A1 gene mutational analysis of 31 patients, 18 patients were confirmed the diagnosis of GLUT1-DS, 1 patient was diagnosed as suspected GLUT1-DS, and 12 patients were excluded the diagnosis of GLUT1-DS. 2． Eighteen patients were diagnosed with GLUT1-DS, of which SLC2A1 gene mutations were found in 15 cases. Patient 1 had large scale deletion in exon 1 to 10. Patient 2 had large scale deletion in exon 1 and 2. Six missense mutations were detected: c.1199G>A (p.R400H) in patient 3, c.1372C>T (p.R458W) in patient 4, c.997C>T (p.R333W) in patient 10, c.1148C>A (p.P383H) in patient 11, c.1198C>T (p.R400C) in patient 13, and c.985G>A(p.E329K) in patient 14. Three ion/deletion mutations: c.332dupG (p.G111fs) in patient 5, c.599delA (p.Q200fs) in patient 8, c.761delA (p.E254fs) in patient 12. A same nonsense mutations c.988C>T (p.R330X) were found in patient 9 and 17. A mutation at animo-acid 1 was found in patient 15. A splice-site mutation of c.680-11G>A (p.227_228insPPV) was found in patient 16. No mutation were found in Patient 6 and 7. 3． The clinical features of 18 patients with confirmed GLUT1-DS: (1) Patients 1 to 7 were the cases with classic type of GLUT1–DS. The clinic manifestations including infantile-onset intractable seizures, development delay, movement disorder, acquired microcephaly and non-epileptical paroxysmal events. Patients 8 to 18 were the cases with paroxysmal ataxia, dystonia or behavior disturbance, and they were diagnosed with atypical GLUT1-DS. (2) Seventeen patients had at least one time CSF tests. Hypoglycorrhachia with the absence of hypoglycemia was found in all the patients at least once. CSF glucose level ranged from 1.17mmol/L to 2.25mmol/L, the mean is 1.82mmol/L. The ratios of CSF glucose to plasma glucose ranged from 0.23 to 0.50, the mean is 0.37. (3) Ten patients had abnormal EEG with diffuse or focal epileptic disges. Slow waves were found in 2 patients. Seizures were recorded in five patients during EEG test. Interictal EEG of one patient was much improved after diet, which is a specific acteristic of GLUT1-DS. (4) Sixteen patients had MRI tests. MRI abnormalities were found in six patients, 3 with hypomylination, 2 with mild brain atrophy and 1 patient with lateral ventricle enlargement. (5) Twelve patients had been treated with ketogenic diet, nine patients had good outcomes, 1 patient had partial, and 2 patients without effect. All the non-classic patients without treatment improved over time except one. 4． CSF glucose in classic patients was lower than that of non-classic patients, but it did not reach the statistic significant difference. CSF glucose of patients with missense and splice-site mutation was higher than that of patients with d mutation, but it did not reach the statistic significant difference. Missense and d mutations were found in both classic and non-classic patients without reaching the statistic significant difference. Two patients with large deletions had classic phenotype, and had lower CSF glucose than that of patients with other type mutations. 5． One patient is still on doubt of the diagnosis of GLUT1-DS, though he had the SLC2A1 gene mutation A405T. The patient showed paroxymal impaired consciousness and dystonia. CSF glucose was normal or slightly decreased. His father has the same mutation with totally normal phenotype. 6． Of the non-GLUT1-DS patients, 8 patients had early-onset refractory seizures, 3 patients had both seizures and proxysmal movement disorder, and 1 had proxysmal movement disorder only. Six patients had normal CSF glucose and 5 patients had slightly decreased CSF glucose. The ratio of CSF/serum glucose was normal or slightly decreased. No CSF test was performed on a patient with infantile–onset intractable seizures. SLC2A1 gene mutations were negative in all the patients. Conclusions 1． The clinical manifestations of glucose transporter type 1 deficiency syndrome vary significantly. The diagnosis of GLUT1-DS should be considered when patients have infantile-onset intractable seizures and development delay, or paroxysmal ataxia, dystonia, behavior disturbance, especially when the symptoms induced or aggravated by the factors such as fasting, fatigue or exercise. 2． Hypoglycorrhachia without hypoglycaemia, or the CSF/serum glucose ratio decreased are the specific acteristic feature of GLUT1-DS. Lumbar puncture is a vital test for the diagnosis of GLUT1-DS. Patients had clinical manifestations mimic GLUT-DS with normal or mild decrease of CSF glucose, mutational analysis of SLC2A1 is essential for the diagnosis. 3． SLC2A1 mutation is the golden standard of diagnosis of GLUT1-DS. However, SLC2A1- negative is seen in some cases. 4． There is no difference of CSF glucose between the classic and non-classic GLUT1-DS patients. In consideration of the small group, further test of more cases is necessary. 5． No differences of CSF glucose or phenotype are found among patients with different mutation types. Large deletions may associate with severe clinical phenotype. In consideration of the small group, further test of more cases is necessary. 6． GLUT1-DS is a treatable neurometabolic disorder. ketogenic diet could improve the prognosis of patients. Some patients had no response to ketogenic diet. There must be some other mechanisms in the pathogenesis of GLUT1-DS except the energy deficiency of the brain.
|张世敏. 葡萄糖转运子I缺乏综合征的临床与基因突变特点和随访研究[D]. 北京大学第一临床医学院. 北京大学,2016.|