Telomere length linked to muscle disease

An inherited muscle disease known as facioscapulohumeral muscular dystrophy (FSHD) which affects the face, shoulders and upper arms, occurs in approximately 1 in every 12,000 people with symptoms first appearing in the second or third decade of life.

A team of researchers in Saudi Arabia and the United States have demonstrated how the shortening of telomeres — the tips of chromosomes — can affect DUX4, a gene related to FSHD, publishing their findings in Nature Structural and Molecular Biology¹.

They compared telomere length with the expression of DUX4 protein in the cells of FSHD patients and their unaffected siblings. There was over ten times more DUX4 in FSHD patient cells and, the shorter the telomeres, the greater the production of DUX4.

This finding could explain the delayed onset of FSHD. Telomeres shorten with age, and a process known as telomere position effects (TPE) could change gene expression near the end of the chromosome. This would make FSHD the first disease in which shorter telomeres contributes to an age-related phenotype.

The next step is to investigate whether individuals who go on to develop the disease long after their siblings have longer telomeres.

"A positive result would go a long way towards establishing the in vivo relevance of our findings and would explain much of the variable penetrance of this perplexing disease," says Woodring Wright, a cell biologist at Southwestern Medical School in Dallas, Texas, and one of the authors of the paper.

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