Novel CLCN1 mutations and clinical features of Korean patients with myotonia congenita.
Myotonia congenita (MC) is a form of nondystrophic myotonia caused by a mutation of CLCN1, which encodes human skeletal muscle chloride channel (CLC-1). We performed sequence analysis of all coding regions of CLCN1 in patients clinically diagnosed with MC, and identified 10 unrelated Korean patients harboring mutations. Detailed clinical analysis was performed in these patients to identify their clinical characteristics in relation to their genotypes. The CLCN1 mutational analyses revealed nine different point mutations. Of these, six (p.M128I, p.S189C, p.M373L, p.P480S, p.G523D, and p.M609K) were novel and could be unique among Koreans. While some features including predominant lower extremity involvement and normal to slightly elevated creatine kinase levels were consistently observed, general clinical features were highly variable in terms of age of onset, clinical severity, aggravating factors, and response to treatment. Our study is the first systematic study of MC in Korea, and shows its expanding clinical and genetic spectrums.
Moon
In-Soo
IS
Department of Neurology, Dae-Dong Hospital, Busan, Korea.
Kim
Hyang-Sook
HS
Shin
Jin-Hong
JH
Park
Yeong-Eun
YE
Park
Kyu-Hyun
KH
Shin
Yong-Bum
YB
Bae
Jong Seok
JS
Choi
Young-Chul
YC
Kim
Dae-Seong
DS
D000328:Adult; D000595:Amino Acid Sequence; D044466:Asian People / Q000235:genetics*; D001483:Base Sequence; D002675:Child, Preschool; D018118:Chloride Channels / Q000235:genetics*; D004252:DNA Mutational Analysis; D005091:Exons; D006801:Humans; D007223:Infant; D007723:Korea; D008297:Male; D008969:Molecular Sequence Data; D009224:Myotonia Congenita / Q000235:genetics*; D017354:Point Mutation; D011487:Protein Conformation; D055815:Young Adult
C086321:CLC-1 channel; D018118:Chloride Channels