Prenatal Diagnosis of the 22q11.2 Duplication Syndrome

  • Lee, Moon-Hee (Laboratoy of Medical Genetics, Cheil General Hospital & Women's Healthcare Center, Kwandong University, College of Medicine) ;
  • Park, So-Yeon (Laboratoy of Medical Genetics, Cheil General Hospital & Women's Healthcare Center, Kwandong University, College of Medicine) ;
  • Lee, Bom-Yi (Laboratoy of Medical Genetics, Cheil General Hospital & Women's Healthcare Center, Kwandong University, College of Medicine) ;
  • Choi, Eun-Young (Laboratoy of Medical Genetics, Cheil General Hospital & Women's Healthcare Center, Kwandong University, College of Medicine) ;
  • Kim, Jin-Woo (Laboratoy of Medical Genetics, Cheil General Hospital & Women's Healthcare Center, Kwandong University, College of Medicine) ;
  • Park, Ju-Yeon (Laboratoy of Medical Genetics, Cheil General Hospital & Women's Healthcare Center, Kwandong University, College of Medicine) ;
  • Lee, Yeon-Woo (Laboratoy of Medical Genetics, Cheil General Hospital & Women's Healthcare Center, Kwandong University, College of Medicine) ;
  • Oh, Ah-Rum (Laboratoy of Medical Genetics, Cheil General Hospital & Women's Healthcare Center, Kwandong University, College of Medicine) ;
  • Lee, Shin-Young (Laboratoy of Medical Genetics, Cheil General Hospital & Women's Healthcare Center, Kwandong University, College of Medicine) ;
  • Yang, Jae-Hyug (Department of Obstetrics and Gynecology, Cheil General Hospital & Women's Healthcare Center, Kwandong University, College of Medicine) ;
  • Ryu, Hyun-Mee (Laboratoy of Medical Genetics, Cheil General Hospital & Women's Healthcare Center, Kwandong University, College of Medicine)
  • Received : 2009.12.15
  • Accepted : 2009.12.27
  • Published : 2009.12.01

Abstract

The 22q11.2 duplication syndrome is an extremely variable disorder with a phenotype ranging from normal to congenital defects and learning disabilities. Recently, the detection rate of 22q11.2 duplication has been increased by molecular techniques, such as array CGH. In this study, we report a familial case of 22q11.2 duplication detected prenatally. Her first pregnancy was terminated because of 22q11.2 duplication detected incidentally by BAC array CGH. The case was referred due to second pregnancy with same 22q11.2 duplication. We perfomed repeat amniocentesis for karyotype and FISH analysis. Karyotype analysis from amniocytes and parental lymphocytes were normal, while FISH analysis of interphase cells presented a duplication of 22q11.2 in the fetus and phenotypically normal mother. The fetal ultrasound showed grossly normal finding. After genetic counseling about variable phenotype with intrafamilial variability with 50% recurrence rate, the couple decided to continue the pregnancy. The newborn had no apparent congenital abnormalities until 2 weeks after birth. We recommend that family members of patients with a 22q11.2 duplication be tested by the interphase FISH analysis. Also, we point out the importance of genetic counseling and an evaluation of the clinical relevance of diagnostic test results.

22q11.2미세중복 증후군은 학습장애, 선천적 기형에서부터 정상에 이르기까지 다양한 표현형을 나타내는 증후군으로써, 22q11.2 미세결실 증후군인 DiGeorge 증후군과 동일한 위치에서 발생하는 질환이며, 이러한 원인은 유전적 불안정성이 높은 low-copy repeats (LCR) 부위에서 일어나는 유전체의 결손이나 중복에 의해 형성되는 것으로 보고되고 있다. 최근 array CGH가 임상분야에 적용됨에 따라 22q11.2 미세중복 증후군의 진단이 증가되고 있다. 이론적으로 22q11.2 부위의 미세중복이나 미세결실의 빈도는 동일하게 발생해야 하지만, 현재까지 미세결실에 비해 미세중복의 증례보고는 상대적으로 드물며 이는 증상이 없는 경우가 많기 때문인 것으로 알려져 있다. 특히 이전 보고에서 산전에 발견된 미세중복의 증례는 단1례 만이 보고된 바 있다. 저자들은 산전에 진단된 22q11.2 미세중복 증후군 1례의 보고를 통해 유전상담의 중요성과 array CGH의 임상 적용에 관하여 논하고자 한다.