Joint deformities may be caused by oversensitive sensory neurons: Study
Distal arthrogryposis (DA) is a disorder characterized by congenital joint deformities, or contractures, that often restrict movement in the hands and feet and is estimated to afflict roughly one in 3,000 individuals worldwide. Alleviating the symptoms often requires invasive surgeries. Although mutations in genes associated with muscle and joint function have been linked to DA, gain-of-function mutations in PIEZO2 - a principal mechanosensor in sensory neurons that underlies touch sensation, proprioception, and other mechanosensory processes - have been found in patients with DA subtype 5 (DA5).
However, the mechanism by which PIEZO2 mutations cause DA is unknown. Using a mouse model, Shang Ma and colleagues found that over-expression of the mutant Piezo2 gain-of-function allele in proprioceptive neurons that enervate muscles and tendons during a critical postnatal period during development can cause joint contracture. These defects were not caused when the dysfunctional allele was expressed in skeletal muscles, cartilage, or tendons.
Excessive mechanosensation in the neurons that enable the sense of one’s limbs in space can disrupt musculoskeletal development and cause joint deformities like arthrogryposis, researchers report. Their study also provides proof of concept that reducing this heightened sensory neuronal activity (via Botox or special diet) during a critical age could be a viable way to treat some musculoskeletal conditions in a non-invasive manner.
According to Ma et al., Botox injection and a dietary fatty acid commonly found in fish reduced joint and tendon defects. “The study by Ma et al. provides exciting new insights into the mechanisms that cause DA,” writes Urich Müller in a related Perspective. “Finding that expression of the gain-of-function allele of Piezo2 in young adult mice does not cause DA symptoms is reassuring. It narrows down a time window for potential therapeutic intervention that could lead to lifelong improvement for the affected patients.”
Reference:
Shang Ma et al,Excessive mechanotransduction in sensory neurons causes joint contractures,Science,doi 10.1126/science.add3598
Disclaimer: This website is primarily for healthcare professionals. The content here does not replace medical advice and should not be used as medical, diagnostic, endorsement, treatment, or prescription advice. Medical science evolves rapidly, and we strive to keep our information current. If you find any discrepancies, please contact us at corrections@medicaldialogues.in. Read our Correction Policy here. Nothing here should be used as a substitute for medical advice, diagnosis, or treatment. We do not endorse any healthcare advice that contradicts a physician's guidance. Use of this site is subject to our Terms of Use, Privacy Policy, and Advertisement Policy. For more details, read our Full Disclaimer here.
NOTE: Join us in combating medical misinformation. If you encounter a questionable health, medical, or medical education claim, email us at factcheck@medicaldialogues.in for evaluation.