Finding Your CMT Gene – The Distant Cousin Project

Distant Cousin Project

The effort to identify genes that cause rare diseases is more important than ever since effective treatments for genetically caused rare diseases are within sight. For example, gene therapy is on the horizon and has actually been successfully used for other diseases such as Spinal Muscular Atrophy. Researchers in Dr. Stephan Zuchner’s team at the University of Miami recently identified a heretofore unknown CMT gene and also identified a potential cure for the variant. Almost overnight, patients with this culprit literally went from not knowing what gene caused their disease to knowing the gene and to having a potential treatment.

Unfortunately, more than half of the individuals diagnosed with Type 2 CMT have not had their culprit gene identified, and it is impossible to “fix” a gene and difficult to treat a genetic disease if one doesn’t know which gene it is that needs to be fixed or treated. The Distant Cousin Project hopes to speed up the rate at which Type 2 CMT culprit genes are identified.

Intuitively, it might seem that having one’s genome and the genomes of family members with the same disease sequenced should lead to a discovery of the culprit. To some extent, that’s true. The problem is that researchers can readily identify hundreds of potential culprit genes (variations of unknown significance), and you share too much DNA with close relatives to narrow the genes down to just a few possibilities. However, if one was able to locate a distant cousin with the same causal gene, the number of potential culprits could be reduced to one or two. For example, fourth cousins share about only about one-fifth of one percent of their DNA. If two fourth cousins share the same culprit gene, there is a very good chance that researchers could locate it. Of course, it is possible that fourth cousins with CMT might have different causal genes.

A new study will pay for sequencing of the first 10 sets of eligible families with an unidentified form of CMT. The genomes will be sequenced as part of Dr. Zuchner’s research studies at University of Miami and analyzed by the Genesis Project database. There is no cost to the patient – this is free due to the grant by the CMTA which came from a generous donor who is passionate about this project.

The success of the study will depend on the efforts of CMT patients, who have an unidentified culprit gene. You can take part by doing some detective work in your own family. Maybe you will discover distant family members with signs of CMT, who are willing to join.

Eligible families include:

  • Cause of CMT is unclear despite genetic testing.
  • One of your parents is affected with CMT.
  • Existence of a distant cousin, or other distant relative on that parent side, who also has an unidentified form of CMT. This is the most difficult part of the challenge, but we’re relying on the creativity and determination of patients to accomplish this.
  • If the patient and their cousin have not been to one of the CMTA Centers of Excellence, ideally, they have a specialized physician at such a center confirm the CMT diagnosis.
If you think you qualify for this study, please contact the study coordinator Lisa Abreu directly at l.abreu@med.miami.edu. She will consent you and your distant family member via phone or Zoom, ask for some study details and especially a pedigree, and organize a blood draw. The latter will either happen at your doctor’s office or we can schedule a specialized health worker to visit you at home for a blood draw.