MAPT and Parkinson disease: This testing showed the patient to be heterozygous for the splice site mutation C915 +16 C > T at the exon 10/intron 10 boundary (denoted 10 +16), indicating a diagnosis of frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17) (Online Mendelian Inheritance in Man, catalogue entry +157140) [12,13].