A Case of Glycogen Storage Disease Type III Diagnosed by Gene Panel Sequencing

유전자 패널 검사로 진단된 당원병 III형 증례

  • Kim, Seong Wan (Department of Pediatrics, Ajou University Hospital, Ajou University School of Medicine) ;
  • Jang, Ju Young (Department of Pediatrics, Ajou University Hospital, Ajou University School of Medicine) ;
  • Lee, Jang Hoon (Department of Pediatrics, Ajou University Hospital, Ajou University School of Medicine) ;
  • Sohn, Young Bae (Department of Medical Genetics, Ajou University Hospital, Ajou University School of Medicine) ;
  • Jang, Ja-Hyun (Green Cross Genome)
  • 김성완 (아주대학교 의과대학 아주대학교병원 소아청소년과) ;
  • 장주영 (아주대학교 의과대학 아주대학교병원 소아청소년과) ;
  • 이장훈 (아주대학교 의과대학 아주대학교병원 소아청소년과) ;
  • 손영배 (아주대학교 의과대학 아주대학교병원 의학유전학과) ;
  • 장자현 (녹십자지놈)
  • Published : 2020.06.30

Abstract

Type III Glycogen storage disease (Type III GSD, OMIM#232400) is a genetic metabolic disorder in which undigested glycogen accumulates in the organs due to lack of glycogen debranching enzyme caused by AGL mutation. The clinical symptoms of type III GSD include hepatomegaly, delayed growth, hypoglycemia and muscle weakness. These clinical symptoms are similar to those of other types of GSD, making it difficult to distinguish clinically. The authors report a case of type III GSD diagnosed by gene panel sequencing. A 11-month old male patient was presented with hepatomegaly. In liver biopsy, glycogen was accumulated in hepatocytes, suggesting GSDs. For differential diagnosis of types of GSD, gene panel sequencing for GSDs was performed. As a result, two novel pathogenic compound heterozygous variants: c.311_312del (p.His104Argfs*15) and c.3314+1G>A in AGL were detected and the patient was diagnosed as type III GSD. After diagnosis, he started dietary treatment with cornstarch, and has been free from complications. After two years, two same variants were also identified in the chorionic villous sampling of the pregnant mother, and the fetus was diagnosed as type III GSD. Gene panel sequencing is useful for diagnosis of disease which is indistinguishable by clinically and has high genetic heterogeneity, such as GSD. After diagnosis, familial genetic analysis can provide adequate genetic counseling and rapid diagnosis.

당원병 III형은 GDE 결핍으로 분해되지 않은 당원이 간 또는 근육에 축적되는 유전대사이상질환이다. AGL 유전자 변이에 의해 발생하고 높은 유전적 이질성을 가지고 있다. 당원병 III형의 임상증상은 간 비대, 성장 지연, 저혈당 등이 있다. 이러한 임상 증상은 다른 타입의 당원병의 증상과 비슷하여 임상적으로는 구분하기가 어렵다. 저자들은 간 비대 주소로 내원한 11개월 환아에서 유전자 패널 검사로 진단된 당원병 III형 증례를 보고하고자 한다. 간 조직검사결과 간세포에 글리코겐이 축적되어 있어 당원병을 의심하였으며, 당원병 아형의 감별 진단을 위해 유전자 패널 검사를 시행하였다. 그 결과, AGL 유전자에서 이전에 보고된 바 없는 c.311_312del와 c.3314+1G>A 변이가 이형접합체로 발견되어 당원병 III형으로 진단하였다. 진단 후 생옥수수 전분가루를 복용하는 식이요법 시작하였고, 생후 35개월인 현재까지 급·만성 합병증 없는 상태이다. 또한, 가족 검사를 통해 부모가 각각 보인자임을 확인하였고, 임신된 동생의 융모막 검사에서도 동일한 변이가 확인되어 출산 후 재검 및 조기 식이요법을 시행할 예정이다. 유전자 패널 검사법은 당원병과 같이 임상적으로 구분이 어려우며 높은 유전적 이질성을 가진 질환의 감별 진단 시 시간과 비용을 아낄 수 있어 유용하다. 또한 정확한 분자 유전학적 진단은 환아와 가족에게 질환에 대한 정확한 정보 및 치료 예방, 산전 유전상담을 제공하는 데 도움이 된다.

Keywords

References

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