Monozygotic Twins with Frontotemporal Dementia Due To Thr272fs GRN Mutation Discordant for Age At Onset

J Alzheimers Dis. 2019;67(4):1173-1179. doi: 10.3233/JAD-180723.


We report the case of two monozygotic twins with Thr272fs mutation in progranulin gene. Both patients developed frontotemporal dementia with 5 years difference in age at onset (Twin 1:73 years, Twin 2:68 years), with early behavioral, language, dysexecutive, and memory problems. They had the same formal education (5 years), but while Twin 1 dedicated more to social and leisure activity, Twin 2 worked all her life. At neuroimaging (MRI for Twin 1 and CT for Twin 2), they both showed asymmetric atrophy with left predominance. The two were discordant for total tau levels in cerebrospinal fluid, neuropsychological testing, and smoking habits. The description of the twins can help identify environmental factors that influence the onset and phenotype of frontotemporal dementia.

Keywords: Age at onset; atrophy; cerebrospinal fluid; frontotemporal dementia; progranulin (GRN); twins.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Atrophy
  • Behavioral Symptoms* / diagnosis
  • Behavioral Symptoms* / psychology
  • Brain* / diagnostic imaging
  • Brain* / pathology
  • Disease Progression
  • Epigenesis, Genetic
  • Female
  • Frontotemporal Dementia* / diagnosis
  • Frontotemporal Dementia* / genetics
  • Frontotemporal Dementia* / psychology
  • Humans
  • Magnetic Resonance Imaging / methods
  • Mutation
  • Neuroimaging / methods
  • Neuropsychological Tests
  • Progranulins / genetics*
  • Tomography, X-Ray Computed / methods
  • Twins, Monozygotic


  • GRN protein, human
  • Progranulins