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Difficult case of a rare form of familial Alzheimer’s disease with PSEN1 P117L mutation
  1. Ana Luísa Rocha1,
  2. Andreia Costa1,
  3. Maria Carolina Garrett1 and
  4. Joana Meireles2
  1. 1 Department of Neurology, Centro Hospitalar e Universitário de São João, Porto, Portugal
  2. 2 Department of Neurology, Centro Hospitalar do Tâmega e Sousa, Penafiel, Portugal
  1. Correspondence to Professor Maria Carolina Garrett, garrett.mc51{at}


Less than 10% of Alzheimer’s disease (AD) cases are familial. Presenilin-1 (PSEN1) mutations are the most frequent aetiology and may be associated to atypical neurological manifestations. We report the case of a 27-year-old right-handed man, ensuing with mild cognitive impairment, motor discoordination and axial myoclonus after a parachute accident. At age 32 he was referred to our neurology clinic, presenting cognitive impairment, cerebellar syndrome, axial myoclonus and hypomimia, without other signs of parkinsonism. Because of absence of family history, he was worked up along the line of spinal ataxic disorders. Later, he developed pseudobulbar affect, cognitive deterioration, right upper limb paresis and spastic paraparesis. Subsequent investigation identified a PSEN1 P117L mutation and the diagnosis of autosomal dominant AD was made. This case illustrates the diagnostic challenge imposed by atypical presentation of de novo PSEN1 mutation, leading to unnecessary investigation. Genetic study might be essential for defining the diagnosis.

  • memory disorders
  • neuro genetics
  • dementia, Alzheimer’s type
  • neurology (drugs and medicines)

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  • Contributors ALR followed the patient and planned and wrote the manuscript. AC, JM and MCG also followed the patient, had a great impact in the diagnostic process and gave a great contribution in manuscript planning and review.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.