In line with this hypothesis, fragmented and dysfunctional mitochondria were found in fibroblasts obtained from G2019S carriers (Grünewald et al., 2014), and treatment with a pharmacological inhibitor of DLP1 was able to reduce mitochondrial fragmentation in LRRK2 G2019S-expressing cells and PD patient fibroblasts (Su and Qi, 2013). The gene discussed is LRRK2; the disease is Parkinson disease.