| 근긴장성 이영양증의 삼핵산 반복서열에 관한 연구 |
| 진동규, 김병준, 이광호, 이문향, 오필수, 전계원, 황혜진, 노혜원, 김성진, 여성희, 유종상
삼성서울병원 소아과. 신경과, 삼성생명과학연구소 임상의학과 |
| 삼성서울병원 소아과. 신경과, 삼성생명과학연구소 임상의학과 |
| A study of trinucleotide repeat expansions in myotonic dystrophy |
| Dong Kyu Jin, M.D., Byoung Joon Kim, M.D., Kwang Ho Lee, M.D., Mun Hyang Lee, M.D., Phil Soo Oh, M.D., Kye Won Jeon, M.S., Hye Zin Hwang, M.,S., Hye Won Noh, M.S, Sung Jin Kim, M.S., Sung Hee Yeo, Ph.D., Jong Sang Yu |
| Department of Pediatrics, Department of Neurology, Samsung Medical Center, Clinical Research Center, Samsung Biochemical Research Institute. |
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| Abstract |
Purpose; The trinucleotide repeat expansion in the 3' untanslated resion of the gene is known to be the cause of myotonic dystrophy which is one of most common neurodegenerative disorder manifested by myotonia, cataract, mental retardation and even respiratory distress in neonates. The hereditary pattern of myotonic dystrophy shows more severe symptoms and shows earlier onset with successive generations and congenital cases, the most severe form of myotonic dystrophy,. Occurs by maternal transmission. This genetic transmission mode does not follow Mendelian genetic trait. To find the molecular genetic abnormalities of Korean myotonic dystrophy patients, we investigated the general distribution of myotonic dystrophy alleles and compared the results with referred patients.
Methods: During an 8 month study, from June 1995 to February 1996, 5 patients were referred with presumed diagnosis of myotonic
dystrophy. Among these patients, four cases were confirmed to have the disease by
clinical and electrophysiological findings. We included family members of the studied
probands and 50 normal blood donor DNAs were included as controls. The DNAs of
the enrolled cases were evaluated by Southern blot. Subsequently, copy numbers of the
repeats were determined using PCR amplification.
Results: (1) Two peaks were found
in the distribution of trinucleotide repeats in the normal Korean population. One peak
had 5 copies and the other had 11 to 13 copies. The highest number of copies was 27.
(2) Of the referred cases, 4 pedigrees showed typical expanded repeats. (3) The
minimum expanded copy number was 55 and we were able to detect the expanded band
only by PCR in 2 cases. In other cases, expaded bands were visible by Southern
blotting. (4) There were trend of earlier onset of the disease, progressive worsening
symptoms and larger expanded bands with successive generations.
Conclusion: We
established the methodology for myotonic dystrophy DNA diagnosis using Southern blot
and PCR amplification based on the normal Korean allele distribution. These methods
might be useful in genetic counselling and detection of minimally affected myotonic
dystrophy patients. Key Words: Myotonic dystrophy, DNA diagnosis, Trinucleoide repeat |
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