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Clinical and genetic analysis of the first known Asian family with myotonic dystrophy type 2.

Nakayama T, Nakamura H, Oya Y, Kimura T, Imahuku I, Ohno K, Nishino I, Abe K, Matsuura T - J. Hum. Genet. (2014)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Yokohama Rosai Hospital, Yokohama, Japan.

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.

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Related in: MedlinePlus

Pedigree of the sibling cases carrying the DM2 expansion. The parents did not suffer from muscle weakness and died at the ages of 67 and 72 years. The gender of the unaffected siblings and children of the affected cases is obscured to protect privacy.
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fig1: Pedigree of the sibling cases carrying the DM2 expansion. The parents did not suffer from muscle weakness and died at the ages of 67 and 72 years. The gender of the unaffected siblings and children of the affected cases is obscured to protect privacy.

Mentions: The pedigree studied is shown in Figure 1. DNA was extracted from peripheral blood samples obtained from the three affected family members with their informed consent. Approval for the study was obtained from the ethics committees of Okayama University, Nagoya University Graduate School of Medicine and the National Center of Neurology and Psychiatry.


Clinical and genetic analysis of the first known Asian family with myotonic dystrophy type 2.

Nakayama T, Nakamura H, Oya Y, Kimura T, Imahuku I, Ohno K, Nishino I, Abe K, Matsuura T - J. Hum. Genet. (2014)

Pedigree of the sibling cases carrying the DM2 expansion. The parents did not suffer from muscle weakness and died at the ages of 67 and 72 years. The gender of the unaffected siblings and children of the affected cases is obscured to protect privacy.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3973124&req=5

fig1: Pedigree of the sibling cases carrying the DM2 expansion. The parents did not suffer from muscle weakness and died at the ages of 67 and 72 years. The gender of the unaffected siblings and children of the affected cases is obscured to protect privacy.
Mentions: The pedigree studied is shown in Figure 1. DNA was extracted from peripheral blood samples obtained from the three affected family members with their informed consent. Approval for the study was obtained from the ethics committees of Okayama University, Nagoya University Graduate School of Medicine and the National Center of Neurology and Psychiatry.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Yokohama Rosai Hospital, Yokohama, Japan.

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.

Show MeSH
Related in: MedlinePlus