CAJ | 학술논문

目的了解先天性中枢性低通气综合征(congenital central hypoventilation syndrome,CCHS)新生儿的分子遗传学发病机制,并通过检索文献,对基因型和表型关联性进行分析. 方法总结复旦大学附属儿科医院2013年1月至2013年8月临床诊断的2例CCHS新生儿的临床资料.收集2例患儿的临床信息,同时提取基因组DNA,对PHOX2B及RET基因编码区进行聚合酶链反应扩增,产物经纯化后直接测序.采用Mutation Surveyor软件分析.同时检索国内外文献,进行基因型和表型关联分析. 结果 2例均为男性.例1为早产儿,出生时有窒息,生后以呼吸机依赖和腹胀为主要表现,经手术确诊为全结肠型巨结肠,因呼吸衰竭死亡.例2为足月儿,以反复发绀、呼吸机依赖为主要表现.例1检测到PHOX2B基因3号外显子38 bp杂合缺失突变(c.722 759her del),属于非多聚丙氨酸延展突变(non polyalanine repeat expansion mutations,NPARMs).例2检测到3号外显子小片段插入(c.776_777het_dup),属于多聚丙氨酸延展突变(polyalanine repeat expansion mutations,PARMs).2例患儿RET基因编码区测序均发现7号外显子单核苷酸多态性(rs1800860),c.1296 A＞G,p A 432 A.检索文献发现,至2013年1 2月,全世界报道PHOX2B相关的CCHS共670例,其中90％以上为PARMs,余为NPARMs.表型方面,NPARMs较PARMs更为严重,且巨结肠和肿瘤的发生率更高. 结论 CCHS在新生儿期以呼吸机依赖为主要表现,可合并巨结肠,自主神经紊乱表现可不典型.综合文献,95％以上CCHS由PHOX2B突变引起,NPARMs突变具有更严重的表型,7个以上GCN重复患儿常常需要持续通气支持治疗,其基因诊断结果可作为CCHS的确诊依据,并可协助指导治疗和判断预后.
목적 료해선천성중추성저통기종합정(congenital central hypoventilation syndrome,CCHS)신생인적분자유전학발병궤제,병통과검색문헌,대기인형화표형관련성진행분석. 방법 총결복단대학부속인과의원2013년1월지2013년8월림상진단적2례CCHS신생인적림상자료.수집2례환인적림상신식,동시제취기인조DNA,대PHOX2B급RET기인편마구진행취합매련반응확증,산물경순화후직접측서.채용Mutation Surveyor연건분석.동시검색국내외문헌,진행기인형화표형관련분석. 결과 2례균위남성.례1위조산인,출생시유질식,생후이호흡궤의뢰화복창위주요표현,경수술학진위전결장형거결장,인호흡쇠갈사망.례2위족월인,이반복발감、호흡궤의뢰위주요표현.례1검측도PHOX2B기인3호외현자38 bp잡합결실돌변(c.722 759her del),속우비다취병안산연전돌변(non polyalanine repeat expansion mutations,NPARMs).례2검측도3호외현자소편단삽입(c.776_777het_dup),속우다취병안산연전돌변(polyalanine repeat expansion mutations,PARMs).2례환인RET기인편마구측서균발현7호외현자단핵감산다태성(rs1800860),c.1296 A＞G,p A 432 A.검색문헌발현,지2013년1 2월,전세계보도PHOX2B상관적CCHS공670례,기중90％이상위PARMs,여위NPARMs.표형방면,NPARMs교PARMs경위엄중,차거결장화종류적발생솔경고. 결론 CCHS재신생인기이호흡궤의뢰위주요표현,가합병거결장,자주신경문란표현가불전형.종합문헌,95％이상CCHS유PHOX2B돌변인기,NPARMs돌변구유경엄중적표형,7개이상GCN중복환인상상수요지속통기지지치료,기기인진단결과가작위CCHS적학진의거,병가협조지도치료화판단예후.
Objective To identify variants in the coding sequence of PHOX2B and RET using Sanger sequencing in two independent neonates with congenital central hypoventilation syndrome (CCHS) and to evaluate genotype-phenotype relationships.Methods Genomic DNA samples were obtained from two CCHS neonates admitted to Department of Neonatology,Children's Hospital of Fudan University in January and August of 2013.The coding regions in PHOX2B and RET were screened using Sanger sequencing.Genotype-phenotype analysis was performed on the basis of extensive literature search.Results Two male patients with CCHS were included in this study.Case 1 was a premature newborn with asphyxia at birth who showed subsequent ventilator dependence and abdominal distension.Hirschsprung disease was confirmed by surgery.Despite active treatment the patient died.Case 2 was a mature newborn who had multiple episodes of cyanosis and showed ventilator dependence.DNA sequencing demonstrated a heterozygous 38 bp deletion within exon 3 from bp 722-759 of the coding region [non-polyalanine repeat expansion mutations (NPARMs) ; genotype c.722_759het_del] in Case 1 and a heterozygous 21 bp polyalanine repeat expansion mutation (PARMs; genotype c.776_777het_dup) in Case 2.A homozygous c.1296 A＞G nucleotide change in RET was detected in both patients which was a common single nucleotide polymorphism (rs1800860).Following a literature review,mutations in PHOX2B were identified in 670 patients with CCHS.Over 90％ of CCHS cases were heterozygous for polyalanine expansion repeat mutations.The remaining patients with a CCHS phenotype were heterozygous for non-polyalanine expansion repeat mutations.Conclusions CCHS may be characterized by ventilator dependence in the neonatal period.Some of CCHS patients are likely to develop Hirschsprung disease.Symptoms of autonomic nervous system dysregulation such as diminished heart rate variability,esophageal dysmotility,and reduced basal body temperature may be atypical.The type of PHOX2B mutation and the length of PARMs determine the severity of CCHS.Patients with NPARMs show a more severe phenotype.Hirschsprung disease is more prevalent in cases with NPARMs.Individuals with genotypes from 20/27 to 20/33 often require continuous ventilatory support,especially as the expanded allele becomes larger.Genetic testing can not only provide evidence for definite diagnosis,but also guide treatment.