title: Low D4Z4 copy number and gender difference in Korean patients with facioscapulohumeral muscular dystrophy type 1.
abstract: The objective of this study was to investigate the clinical and genetic features of Korean patients with facioscapulohumeral muscular dystrophy type 1 (FSHD), and assessed the impact of molecular defects on phenotypic expression. We enrolled 104 FSHD patients from 87 unrelated Korean families with D4Z4 repeat array of less than 11 copies on 4q35. Sixty-one men and forty-three women were enrolled. Median D4Z4 copy number was 4 units and 99 (95%) Korean patients with FSHD carried 1-6 units. The median age at symptom onset was 13 [interquartile range: 8-17] years old. In 100 symptomatic patients, muscle weakness began in facial muscles in 58 patients, shoulder-girdle muscles in 37, and pelvic-girdle muscles in 5. Disease severity was significantly correlated with D4Z4 copy number. In addition, women were more severely affected than men even though there were no differences in age at examination or in D4Z4 copy number between the two genders. This gender difference among Korean patients was the opposite of analysis on individuals of European ancestry. In conclusion, the present study demonstrated the new diagnostic threshold for FSHD in Koreans based on the D4Z4 repeat array size distribution from 1 to 6 units and expanded the clinical spectrum.
authors: Department of Neurology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Republic of Korea; Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors: Hyung Jun
authors: HJ
authors: Park
authors: Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors: Ji-Man
authors: JM
authors: Hong
authors: Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors: Jung Hwan
authors: JH
authors: Lee
authors: Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors: Hyung Seok
authors: HS
authors: Lee
authors: Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors: Ha Young
authors: HY
authors: Shin
authors: Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors: Seung Min
authors: SM
authors: Kim
authors: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Chang-Seok
authors: CS
authors: Ki
authors: Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea.
authors: Ji Hyun
authors: JH
authors: Lee
authors: Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea. Electronic address: ycchoi@yuhs.ac.
authors: Young-Chul
authors: YC
authors: Choi
mesh_terms: D000328:Adult; D005190:Family; D005260:Female; D018628:Gene Dosage; D056726:Genetic Association Studies; D006801:Humans; D007723:Korea / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000473:pathology / Q000503:physiopathology; D020391:Muscular Dystrophy, Facioscapulohumeral / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology*; D012720:Severity of Illness Index; D012727:Sex Characteristics; D055815:Young Adult
keywords: D4Z4 repeat; Facioscapulohumeral muscular dystrophy; Gender difference; Genotype–phenotype relationship