In the past, there have been a variety of research studies exploring and working to learn more about cystinuria, a rare genetic condition causing cystine, an amino acid, to accumulate in the bladder and kidneys. However, researchers from Nara Medical University, the Max Planck Institute of Biophysics, and the Jikei University School of Medicine sought to understand more about the underlying molecular mechanisms driving cystinuria. According to Max-Planck-Gesellschaft, the research specifically focused on rBAT and b0,+AT, two proteins that have previously been associated with cystinuria.
To evaluate rBAT and b0,+AT, the researchers used electron cryo-microscopy alongside various other tools and tests. Learn more about electron cryo-microscopy.
Through the study, the research team discovered calcium ions located in the extracellular rBAT domain. These ions connected multiple rBAT and b0,+AT molecules. Together, the rBAT and b0,+AT molecules formed a super-dimer. Normally, the super-dimer helps to ensure that amino acids and proteins are transported properly throughout the body. However, the research team also discovered that gene mutations associated with cystinuria inhibited the super-dimer’s ability to work properly.
Ultimately, the research team deemed two findings:
- Specific gene mutations associated with this disease cause protein trafficking issues.
- These same mutations and trafficking issues can prevent the super-dimer from working properly, meaning that the super-dimer and its inhibition have been linked to cystinuria development. This could provide an avenue for future research and treatment.
To learn more, take a look at the full study findings published in Nature.
About Cystinuria
SLC3A1 and SLC7A9 gene mutations cause cystinuria which, as described above, is a rare genetic disorder characterized by cystine accumulation. As the cystine builds up, it can form crystals, which can then become stones. When these stones get caught in the kidney or bladder, they can cause a number of health issues, including blockages, bacterial infections, and pain. Cystinuria is inherited in an autosomal recessive pattern, meaning that patients must inherit one defective gene from each parent in order to develop this condition. Typically, symptoms manifest between ages 10 and 30. When symptoms appear, these can include:
- High cystine levels in the urine
- Sharp pain in the lower back or side of the abdomen
- Hematuria (blood in the urine)
- Urinary tract infections or obstructions
- Nausea and vomiting
- Urinary stones
- Kidney damage
Learn more about cystinuria.
