Past studies have shown that our gut microbiota, or the collection of microorganisms (bacteria, archaea, fungi, yeast, viruses) within our gut, plays an immense role in our health. Our gut microbiota can support our immune health but it can also contribute to issues with digestion, cardiovascular health, neurodegeneration, and even your mood. According to an article from Medical XPress, novel research from Macquarie University may have now found a connection between the gut microbiota and the onset of Machado-Joseph disease (MJD).

Within this particular study, the research team sought to explore the relationship between gut microbiota and various forms of spinocerebellar ataxia; MJD exists under this umbrella. To begin, the research team examined mice models of MJD. Their research, published in Neurobiology of Disease, found that levels of bacteria fluctuated in the microbiome before any MJD symptoms appeared. Some levels of this bacteria, which are naturally found in the gut, rose while others fell, leading to microbiome imbalance. . Specifically, Lachnospiraceae, Rikenellaceae, and Oscillospiraceae bacteria were extremely low.

More interestingly, these fluctuations correlated with disease severity. The more these levels fluctuated prior to symptom appearance, the worse the symptoms were.

While this research does provide some initial insight into the role of the gut microbiota in MJD, more research is needed. First, research should examine whether these fluctuating levels are also seen in humans. Are these fluctuations similar in mice models and humans? Can understanding deviations between these fluctuations provide more information about this disease? Additional research should focus on exactly how these fluctuations affect neuronal health and drive MJD.

About Machado-Joseph Disease (MJD)

Also known as spinocerebellar ataxia type 3 (SCA3), Machado-Joseph disease is a rare inherited condition that affects muscle control. There are too many copies of CAG trinucleotide repeats in the DNA due to ATXN3 gene mutations. This causes progressive brain degeneration in the hindbrain; as neurons die, worsening weakness, clumsiness, and other issues occur. MJD seems to significantly affect indigenous communities; the highest MJD prevalence on a global scale is in Groote Eylandt, where many residents are Aboriginal or Torres Strait Islander.

There are three MJD subtypes (I, II, and III) with different onset and disease severity. When symptoms appear earlier, the person often tends to have more severe symptoms.

• Type I typically sees symptom manifestation between 10-30 years old. Unlike other forms, which may progress more slowly, MJD type I is often rapidly progressing. Symptoms may include difficulty swallowing, bulging eyes, difficulty controlling eye movements, a slow and lurching gait, muscle spasticity or rigidity, severe muscle weakness in the extremities, and slurred speech.
• Type II has similar symptoms to Type I. However, MJD type II is slower to progress; symptom onset also happens later, between 20-50 years old. This form is characterized by an unsteady gait, spastic muscle movements, and poor arm and muscle coordination.
• Type III has the latest onset of all MJD subtypes, with symptom onset usually occuring between 40-70 years old. An unsteady gait, abnormal nerve sensations, diabetes, loss of pain sensitivity, and muscle mass degeneration are all seen in this form.

There are no cures for MJD. Neither are there disease-specific treatments. Instead, MJD management is focused on reducing symptoms. Learn more about Machado-Joseph disease.