title: Clinical and genetic analysis of the first known Asian family with myotonic dystrophy type 2.
abstract: Myotonic dystrophy type 2 (DM2) is more common than DM1 in Europe and is considered a rare cause of myotonic dystrophies in Asia. Its clinical course is also milder with more phenotypic variability than DM1. We herein describe the first known Asian family (three affected siblings) with DM2 based on clinical and genetic analyses. Notably, two of the affected siblings were previously diagnosed with limb-girdle muscular dystrophy. Myotonia (the inability of the muscle to relax) was absent or only faintly present in these individuals. The third sibling had grip myotonia and is the first known Asian DM2 patient. The three DM2 siblings share several systemic characteristics, including late-onset, proximal-dominant muscle weakness, diabetes, cataracts and asthma. Repeat-primed PCR across the DM2 repeat revealed a characteristic ladder pattern of a CCTG expansion in all siblings. Southern blotting analysis identified the presence of 3400 repeats. Further DM2 studies in Asian populations are needed to define the clinical presentation of Asian DM2 and as yet unidentified phenotypic differences from Caucasian patients.
authors.affiliation: Department of Neurology, Yokohama Rosai Hospital, Yokohama, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nakayama
authors.affiliation: Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors.forename: Harumasa
authors.initials: H
authors.lastname: Nakamura
authors.affiliation: Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Oya
authors.affiliation: Department of Neurology, Asahikawa Medical Center, National Hospital Organization, Asahikawa, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Department of Neurology, Yokohama Rosai Hospital, Yokohama, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Imahuku
authors.affiliation: Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Kinji
authors.initials: K
authors.lastname: Ohno
authors.affiliation: Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors.forename: Ichizo
authors.initials: I
authors.lastname: Nishino
authors.affiliation: Department of Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Abe
authors.affiliation: 1] Department of Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan [2] Division of Neurology, Department of Medicine, Jichi Medical University, Shimotsuke, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Matsuura
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People / Q000235:genetics*; D015139:Blotting, Southern; D005190:Family; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009223:Myotonic Dystrophy / Q000235:genetics*; D010375:Pedigree; D016133:Polymerase Chain Reaction; D035781:Siblings