【作者】 张娜；

【导师】 陈宗波；

【作者基本信息】 青岛大学 ， 儿科学（专业学位）， 2019， 硕士

【摘要】 目的:对遗传疾病来说,早期发现、早期诊断、早期干预对患者的预后有重要意义。通过回顾性分析2例早发癫痫合并耳聋患儿的临床资料、实验室检查,通过基因测序确定两名无血缘关系患儿的致病突变,从而提高对TBC1D24基因突变相关疾病的认识,达到早期诊断并指导临床治疗的目的。方法:选取2名以早发癫痫合并耳聋为主要临床特征的患儿为研究对象,收集详细的临床资料,主要包括临床表现、全面的体格检查、常规实验室检查,影响学检查(主要是脑MRI),脑电图和代谢筛查。对临床资料进行回顾性分析,同时抽取患儿、患儿父母、患儿哥哥的外周血,参考数据库OMIM以及HGMD,选取相关癫痫基因进行新一代测序(NGS),确认单核苷酸变异结果。然后,运用Poly Phen-2软件、ANNOVAR软件、HGMD数据库、db SNP数据库、1000 Genome数据库进行变异注释。最后,采用Sanger法对候选变异进行验证。结果:患者1为1月18天女婴,以部分性游走性癫痫发作为主要表现,辅助检查示三大常规、肝肾功、心肌酶、电解质指标处于正常范围。遗传代谢筛查指标无阳性结果。颅脑MR未见异常。脑电图有一次有散在性放电。听力学测试示双耳中重度听力损害。给予托吡酯、苯巴比妥、左乙拉西坦、丙戊酸钠等多种抗癫痫药物治疗,仍有抽搐,发育停滞状态,不存在倒退问题。最后猝死于癫痫发作。基因测序在TBC1D24基因中发现复合杂合核苷酸变异:c.116C>T(编码区第116号核苷酸由C变为T)、c.827T>C(编码区第827号核苷酸由T变为C)的杂合核苷酸变异。前者遗传自母亲,哥哥为携带者,后者遗传至父亲。患儿2为1岁2个月女婴,发病年龄为3月龄,以复杂的局灶性肌阵挛为主要表现,系34周+2早产儿,有发热惊厥家族史,发病前无智力发育障碍。辅助检查三大常规,血氨、乳酸等代谢指标,免疫球蛋白测定,调节性淋巴细胞亚群未见明显异常。头颅MR示双侧脑室饱满,双侧额部脑外间隙略宽,右侧小脑半球局限性脑外间隙略宽。3小时视频脑电图未见癫痫波。听力筛查示双侧感音性耳聋。给予左乙拉西坦、丙戊酸钠、氯巴占联合抗癫痫药物治疗,仍有抽搐,平均1月2次左右,发育迟缓,不存在倒退问题。在受检者TBC1D24基因发现复合杂合核苷酸变异:c.404C>T(编码区第404号核苷酸由C变为T)、c.679C>T(编码区第679号核苷酸由C变为T)的杂合核苷酸变异,在受检者TBC1D24基因所发现的复合杂合变异分别遗传自受检者其父母,父母均为杂合子。结论:经过蛋白损伤预测上述变异均可能导致蛋白质功能受到影响。通过对两名没有血缘关系的中国患儿致病基因的分析,我们了解到TBC1D24基因的复合杂合突变(c.116C>T和c.827T>C;c.404C>T和c.679C>T)可能导致一种罕见独特的表型:癫痫,耳聋和发育迟缓。更多还原

【Abstract】 Background and Purpose: In the past ten years,people have gradually realized the multipotency of TBC1D24 gene,involving complex genotype-phenotype association.Different mutations can lead to different developmental disorders of nervous,hearing and skeletal systems,such as epilepsy,deafness,stunting and bone dysplasia.Early detection,early diagnosis and early intervention are important for the prognosis of patients.We report two unrelated Chinese patients with common clinical manifestations: epilepsy,sensorineural deafness and developmental retardation.By retrospective analysis of clinical data,laboratory tests and gene mutation results of 2 children with early epilepsy and deafness,the pathogenic mutations of two unrelated children were identified.To improve the understanding of the disease,to achieve early diagnosis and guide clinical treatment.Methods: Two children with early-onset epilepsy and deafness as the main clinical characteristics were selected as the subjects.Detailed clinical data were collected,including clinical manifestations,comprehensive physical examination,routine laboratory examination,impact study(brain MRI),electroencephalogram and metabolic study.The clinical data were analyzed retrospectively.At the same time,the peripheral blood of children,parents and brothers were collected,and the related epilepsy genes were selected for new generation sequencing(NGS)by referring to OMIM and HGMD databases.Confirmation of single nucleotide mutation results.Then,we use Poly Phen-2 software,ANNOVAR software,HGMD database,db SNP database,1000 Genome database for mutation annotation.Finally,Sanger method was used to validate the candidate mutation.Results: A female infant aged 58 days with refractory seizures was referred to our Center.The type of epileptic seizures is partial migratory seizures.Laboratory tests showed that the three routine indexes,liver and kidney function,myocardial enzymes and electrolytes were in normal range.There was no abnormality in the brain MR.There is a discrete discharge in the EEG.Auditory mechanics tests showed severe hearing impairment in both ears.Treatment with a variety of antiepileptic drugs such as topiramate,phenobarbital,levetiracetam,sodium valproate,there are still convulsions.This child has mental retardation and no developmental regression.The child eventually died of epileptic seizures.Gene sequencing revealed a heterozygous nucleotide variation in the TBC1D24 gene: c.116C>T(nucleotide No.116 of the coding region changed from C to T),c.827T>C(nucleotide No.827 of the coding region)Hybrid nucleotide variation from T to C).The former is inherited from the mother,the latter is passed on to the father.and the older brother is the carrier.Patient 2 was treated at Qingdao Women & Children’s Hospital at the age of 1 year and 2 months.The onset age of the child is 3 months old.The form of seizures is complex focal myoclonus.The child was a premature infant with34+2 weeks and had a family history of febrile seizures.The child had no mental retardation before the onset of the disease.In his family history,her brother had a history of febrile convulsions.Only mild elevation of blood ammonia and lactic acid was detected in routine biochemical tests and metabolic studies.The EEG was normal.Head MRI showed bilateral ventricles full,bilateral cephalic space slightly wider,and the limited outer cerebral space slightly wider in the right cerebellar hemisphere.While we found that the child had a mild bilateral sensorineural hearing loss by using a brainstem auditory evoked potentials test.Epilepsy seizures were treated with levetiracetam,sodium valproate and clobazan,and convulsions could not be controlled.The frequency of epileptic seizures was about 2 times per month on average.The child had developmental retardation,and there was no regression problem.Compound heterozygous nucleotide variants were also found in TBC1D24 gene:c.404 C>T and c.679 T>C.Both of them were de novo missense mutations.The c.404 C>T leads to compile the 135 th amino acid Pro codon to Leu(p.Pro135Leu).The c.679 T>C change the 227 th amino acid from Arg to Trp(p.Arg227Trp).Conclusion: Poly Phen2,SIFT and Mutation Taster software were used to predict protein damage.These variations may lead to impairment of protein function.Complex heterozygous mutations(c.116C>T and c.827T>C;c.404C>T and c.679C>T)of TBC1D24 gene in two unrelated Chinese children can lead to a unique phenotype:epilepsy,deafness and developmental retardation.更多还原