Two novel presenilin-1 mutations (Y256S and Q222H) are associated with early-onset Alzheimer's disease

Judith Miklossy, Kevin Taddei, Domizio Suva, Giuseppe Verdile, Justin Fonte, Christopher Fisher, Anastazija Gnjec, Joseph Ghika, Françoise Suard, Pankaj D. Mehta, Catriona A. McLean, Colin L. Masters, William S. Brooks, Ralph N. Martins*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)


Mutations in the gene encoding presenilin 1 (PS-1) account for 50% of early-onset familial Alzheimer's disease (EOFAD) cases. In this study, we identified two missense mutations in the coding sequence of the presenilin (PS-1) gene in two EOFAD pedigrees. AD was confirmed in one pedigree by autopsy. Mutation analysis of PCR products amplified from genomic DNA templates showed two novel PS-1 mutations resulting in Gln222His and Tyr256Ser. The two novel mutations are located within predicted transmembrane domains five (TM-5) and six (TM-6), respectively, and are associated with very early ages of onset. The Tyr256Ser is associated with one of the youngest age of AD onset, 25 years, which is consistent with a drastic change in function of the altered PS-1 protein. A morphometric analysis of the cortical degenerative changes of the Tyr256Ser case, showed severe involvement of the primary motor cortex, which correlated well with the pyramidal changes, including tetraspasticity. Immunoblot analysis showed the Tyr256Ser case had the greatest expression of Aβ1-40 and Aβ1-42, which was confirmed by ELISA, compared to other PS-1 mutant FAD cases and age-matched controls and, thus, contributes to the severity of the disease pathology.

Original languageEnglish
Pages (from-to)655-662
Number of pages8
JournalNeurobiology of Aging
Issue number5
Publication statusPublished - Sept 2003
Externally publishedYes


  • Early-onset familial Alzheimer's disease
  • Motor dysfunction
  • Presenilin-1 mutation
  • Primary motor cortex
  • Pyramidal signs
  • Tetraspasticity


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