A novel granulin mutation in logopenic variant primary progressive aphasias: Case report and literature review

Background: Primary progressive aphasias (PPA) can be divided into 3 main variants, nonfluent/agrammatic, semantic, and logopenic variant. Logopenic variant PPA(lvPPA) was the third to be described clinically. Majority of these PPA patients harbored mutations in the granulin ( GRN ) gene on chromosome 17q21. Case presentation Based on the reported patient’s clinical and neuroimaging data, we considered a diagnosis of lvPPA, characterized by impaired single-word retrieval in spontaneous speech and naming, and impaired repetition of sentences and phrases, with relatively preserved single-word comprehension, object knowledge, motor speech, and no speech errors in spontaneous speech or naming. MRI of head revealed marked lateral atrophy in the left parietal cortex and a gradual change over a period of six years. A heterozygous 10-bp frameshift deletion (C.274_283del ATGCGGGGAT)was identified in exon 4 of the GRN gene (NM_002087.4), leading to alteration of cysteine to alanine at amino acid 92 and creation of a premature stop codon at position 161. This GRN associated lvPPA presentation is rarely previously reported. Conclusions: We summarized clinical, MRI and genetic features of an lvPPA individual carried a novel GRN mutation. We have provided a clue for exploring the pathogenicity significance of GRN mutation in frontotemporal lobar degeneration(FTLD), which broadens the genetic and phenotypic spectrum of FTLD.