Alternative splicing of exon 10 can lead to imbalance of three microtubule-binding repeats (3R) tau (exclusion of exon 10) and four microtubule-binding repeats (4R) tau (inclusion of exon 10) ratio which were associated with several tauopathies in brain (Pittman et al., 2006). The gene discussed is MAPT; the disease is tauopathy.