title: Similar clinical and neuroimaging features in monozygotic twin pair with mutation in progranulin.
abstract: OBJECTIVE
  To report the phenotypic characterization of monozygotic twins with mutations encoding progranulin (PGRN).
  
  
  METHODS
  We studied a twin pair with an exon 4 gene deletion in the PGRN gene. Both twins had clinical and neuropsychological examinations as well as structural MRI and fluorodeoxyglucose PET (FDG-PET) scans. PGRN gene sequencing was performed followed by progranulin ELISA in plasma.
  
  
  RESULTS
  Both twins manifested symptoms within 3 years of each other, with early behavioral, language, dysexecutive, and memory problems. MRI and FDG-PET imaging demonstrated a strikingly similar topography of findings with clear left hemisphere predominance. Serum progranulin levels in both were well below those from a normal population sample.
  
  
  CONCLUSIONS
  Compared with the heterogeneity seen in many families with PGRN mutations, these monozygotic twins demonstrated strong clinical, neuroimaging, and serum progranulin level similarities, demonstrating the importance of shared genetic profiles beyond environmental influences in the symptomatic expression of the disease.
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, MN, USA.
authors.forename: E
authors.initials: E
authors.lastname: McDade
authors.forename: B F
authors.initials: BF
authors.lastname: Boeve
authors.forename: T M
authors.initials: TM
authors.lastname: Burrus
authors.forename: B P
authors.initials: BP
authors.lastname: Boot
authors.forename: K
authors.initials: K
authors.lastname: Kantarci
authors.forename: J
authors.initials: J
authors.lastname: Fields
authors.forename: V J
authors.initials: VJ
authors.lastname: Lowe
authors.forename: P
authors.initials: P
authors.lastname: Peller
authors.forename: D
authors.initials: D
authors.lastname: Knopman
authors.forename: M
authors.initials: M
authors.lastname: Baker
authors.forename: N
authors.initials: N
authors.lastname: Finch
authors.forename: R
authors.initials: R
authors.lastname: Rademakers
authors.forename: R
authors.initials: R
authors.lastname: Petersen
mesh_terms: D001921:Brain / Q000378:metabolism; D004292:Dominance, Cerebral / Q000235:genetics; D005091:Exons / Q000235:genetics; D019788:Fluorodeoxyglucose F18; D057180:Frontotemporal Dementia / Q000235:genetics* / Q000523:psychology*; D017353:Gene Deletion; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood / Q000235:genetics*; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000523:psychology; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging / Q000379:methods / Q000523:psychology*; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D010641:Phenotype; D049268:Positron-Emission Tomography / Q000379:methods / Q000523:psychology; D000077153:Progranulins; D019275:Radiopharmaceuticals; D014430:Twins, Monozygotic / Q000235:genetics* / Q000523:psychology*
chemical_list: C492314:GRN protein, human; D036341:Intercellular Signaling Peptides and Proteins; D000077153:Progranulins; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18