However, exome sequencing identified a missense mutation, N279K, in exon 10 of MAPT gene, verifying that the early parkinsonian symptoms in this family are caused by the genetic mutation for hereditary frontotemporal lobar dementia.
An N279K missense mutation in exon 10 of the tau gene reported in an American family with pallidopontonigral degeneration (PPND family) was recently found in members of a French kindred with dementia and supranuclear palsy.