Japanese pronounce ‘jisuferurin’(dysferlin) and ‘jisuferurinopachi’(dysferlinopathy) according to Katakana notation.
However, we will call them ‘dysferlin’ and ‘dysferlinopathy’ adhering to the American English pronouciation.
Muscular diseases, LGMD2B, Miyoshi muscular dystrophy and distal anterior compartment myopathy caused by
mutations in the dysferlin gene (DYSF) are referred to as dysferlinopathy, inherited in an autosomal recessive pattern.
The dysferlin gene is located in the short arm of chromosome 2.
We have two dysferlin genes, one from the father and the other from the mother.
If both dysferlin genes mutate, deficiency or functional decline of the dysferlin protein will occur and attenuate
sarcolemmal repair (=plasma membrane repair in skeletal muscle).
Sarcolemma is perpetually injured because the skeletal muscle continuously contractions and relaxations.
If the sarcolemmal wound is not fixed, influx of calcium ions from outside of the cell will cause atrophy of myofibers.
The repetation of this process will result in muscle atrophy and mucle weakness.
In dysferlinopathy patients, degeneration of myofiber is severe.
CK flowing from atrophic myofiber results in a high CK value in the blood.
The dysferlin gene is 150 kb and contains 55 exons.
In Japan, genetic analysis of the dysferlin is performed on a small scale by researchers and medical doctors.
Identification of mutations in the dysferlin gene is performed by PCR-SSCP method covering all exons followed by
DNA sequencing. This is excellent protocol, however, it does not identify all mutations.
We hope that the advancement of tool for genetic analysis will make it possible to facilitate the
identification of mutations.
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