A study explored the use of extracellular miRNA signatures to differentiate between LRRK2 mutation carriers and individuals with sporadic PD [81]. The study identified that miR-29c-3p was differentially expressed between these two groups, while miR-425-5p also showed a trend towards significance. Using prediction models based on these miRNA signatures, researchers could accurately predict group affiliation - whether an individual was a LRRK2 mutation carrier or had sporadic PD. The gene discussed is LRRK2; the disease is Parkinson disease.