The P301S tau mutation occurs within the second repeat of the microtubule binding domain and results in early onset and rapidly progressing Frontotemporal dementia (FTD) with Parkinsonism.43Fig. 4A shows that fibrils formed by 2N4R tau with and without the P301S mutation had distinct Raman fingerprints. The gene discussed is MAPT; the disease is Parkinson disease.