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Genetic tests – FSHDCombing test

The FSHDCombing test will radically transform the accuracy and sensitivity of Facio-scapulo-humeral muscular dystrophy (FSHD) diagnosis. The test provides a precise measurement of the D4Z4 repeats on chromosome 4 and 10. FSHD is linked to a contraction of a repeat array on chromosome 4q and FSHDCombing test clearly identifies the haplotype for all four alleles, and enables a clear differentiation between D4Z4 on the two chromosomes.

Product status

Following the successful completion of the clinical trials of the genetic test developed in partnerhsip with Prof Nicolas Lévy at La Timone Hospital, Marseille (reference laboratory for genetic testing) and in partnership with the Université de la Méditerranée, Genomic Vision launched the marketing of the test in 2013. The development was financially supported by the Association Française contre les Myopathies.

Disease background

The second most prevalent neuromuscular disorder, this autosomal dominant disease manifests in atrophy and weakness in the face, shoulders, and ambulatory muscles. FSHD is associated with a contraction of a repeat array located at the telomeric extremity of chromosome 4q (small arm of chromosome 4). The repeated sequence, 3.3 kb-D4Z4, is present on both chromosomes 4q and 10q, and usually comprises 11-150 copies of tandemly repeated D4Z4.

Limitations of current methods

Current genetic tests are based on Southern blotting, which is laborious and can provide data that is difficult to interpret; yielding uncertain results when D4Z4 repeats on chromosomes 4 and 10 cannot be distinguished.

Principle of the test

The FSHDCombing test uses Molecular Combing Technology in a single and simple assay to provide single DNA stretched molecules for the analysis of the haplotype and precise repeat unit counts of all four 4q and 10q D4Z4 repeat arrays.

Download our FSHDCombing test factsheet to find out more.

Disease statistics

FSHD is thought to affect 1 in 20,000 to 1 in 7,000 people. About 70% of FSHD patients inherit the disease from a parent, while 30 % of cases are sporadic and caused by a spontaneous genetic deletion. FSHD affects all populations throughout the world, i.e. has no particular racial, geographic or ethnic distribution, and while equally prevalent in both sexes, males tend to be more severely affected than females.

FSHDCombing test advantage:

  • Robust
    detects single repeats precisely
  • Increased accuracy
    through single molecule approach
  • Highly sensitive
    depends only on the DNA fragment length
  • Precise, quantitative measurements
    through direct visualization of DNA
  • Economical
    detects all required diagnostic sequences (whole genome in one test)
  • Rapid
    automated process
Genomic Vision