Clinical Features and Genetic Analysis of Homocystinuria Patients in Korea

전형적 호모시스틴뇨증 환자들의 임상적 특성과 유전자분석

  • Lee, Yena (Department of Pediatrics, Soonchunhyang University Hospital) ;
  • Lee, Jeongho (Department of Pediatrics, Soonchunhyang University Hospital) ;
  • Lee, Dong Hwan (Department of Pediatrics, Soonchunhyang University Hospital)
  • 이예나 (순천향대학교 의과대학 부속병원 소아과학교실) ;
  • 이정호 (순천향대학교 의과대학 부속병원 소아과학교실) ;
  • 이동환 (순천향대학교 의과대학 부속병원 소아과학교실)
  • Published : 2015.08.25

Abstract

Purpose: Homocystinuria (OMIM#236200) is a metabolic disease caused by mutation in the CBS gene. This study was conducted to identify the clinical features and prognosis of homocystinuria as well as to find out the CBS gene mutations of the six homocystinuria patients who were receiving treatment in the Pediatric Department at Soonchunhyang University Hospital. Methods: From January 1992 to March 2015, clinical, biochemical, and genetic analyses were performed retrospectively on the six patients diagnosed with classic homocystinuria at Soonchunhyang University Hospital. Results: A total of six patients were included in this study, including three who were diagnosed with homocystinuria at the mean age of $50{\pm}22.5$ days based on their abnormal newborn screening test results. The other three were diagnosed at the mean age of 7, when they visited the hospital for evaluation of developmental delay and lens dislocation. The group diagnosed at early infancy had normal cognitive function, but the other group had varying degrees of mental retardation. Major complications were found only in the group diagnosed after infancy. CBS gene mutation was found in all the patients, and they were all non-responsive to vitamin B6 treatment. At present, all patients' diets are controlled following a methionine-free formula and they are on medication with folic acid, betaine, pyridoxine, and methylcobalamin. Conclusion: Six homocystinuria patients were monitored for up to 23 years. The group diagnosed at early infancy exhibited no major complications. Therefore, early diagnosis is crucial in the prognosis, and homocystinuria must be included in the newborn screening program.

목적: 호모시스틴뇨증은 cystathionine ${\beta}$-synthase의 결핍으로 유발되는 질환이다. 본원에서 치료받고 있는 총 6명 환자들의 임상양상과 유전자 분석을 시행하였다. 방법: 1992년 1월부터 2015년 3월까지 본원에서 전형적 호모시스틴뇨증으로 진단되어 치료 중인 총 6명의 환자들을 대상으로 후향적으로 임상적, 생화학적, 유전자적 분석을 하였다. 결과: 총 6명의 환자가 본 연구에 포함되었으며 이 중 3명은 영아기에 발견되었고, 나머지 3명은 7세 이후에 진단되었다. 영아기에 진단되어 치료를 받은 환자들은 정상 인지기능을 보였고, 7세 이후에 진단된 환자들은 다양한 정도의 지적 장애가 있었다. 골감소증이 6명 중 2명의 환자에서 발견되었다. 혈전 색전증이나 경련, 수정체 탈구 같은 주요한 합병증은 7세 이후에 진단된 군에만 있었다. 유전자 검사에서 모두 cystathionine ${\beta}$-synthase 유전자의 돌연변이를 확인하였다. 본 연구에 포함된 6명은 현재 메티오닌 제한 식이를 하면서 엽산과 베타인, 비타민 B6, 메틸코발라민을 복용 중이다. 결론: 6명의 전형적 호모시스틴뇨증 환자들을 길게는 23년 동안 추적 관찰하였다. 신생아 대사 이상 검사에서 발견된 환자들은 합병증 없이 성장하고 있으나, 7세 이후에 진단된 환자들은 100% 수정체 탈구가 있었고 각종 합병증이 동반되었다. 따라서 전형적 호모시스틴뇨증의 예후에는 무엇보다 조기 진단이 중요하며 이는 현재 국내에서 시행되는 신생아 대사 이상 검사의 중요성을 설명하는 것이라 하겠다.

Keywords

References

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