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

• Published in: Neurobiology of aging Vol. 24; no. 5; pp. 655 - 662
• Main Authors: Miklossy, Judith, Taddei, Kevin, Suva, Domizio, Verdile, Giuseppe, Fonte, Justin, Fisher, Christopher, Gnjec, Anastazija, Ghika, Joseph, Suard, Françoise, Mehta, Pankaj D, McLean, Catriona A, Masters, Colin L, Brooks, William S, Martins, Ralph N
• Format: Journal Article
• Language: English
• Published: London Elsevier Inc 01-09-2003; Elsevier Science
• Subjects: Adult; Alzheimer Disease - genetics; Amino Acid Substitution; Amyloid beta-Peptides - metabolism; Biological and medical sciences; Blotting, Western; Brain - metabolism; Brain - pathology; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; DNA Mutational Analysis; Early-onset familial Alzheimer’s disease; Enzyme-Linked Immunosorbent Assay; Family Health; Female; Glutamine - genetics; Histidine - genetics; Humans; Immunohistochemistry; Medical sciences; Membrane Proteins - genetics; Motor dysfunction; Mutation, Missense; Neurology; Pedigree; Peptide Fragments - metabolism; Plaque, Amyloid - pathology; Presenilin-1; Presenilin-1 mutation; Primary motor cortex; Pyramidal signs; Serine - genetics; Tetraspasticity; Tyrosine - genetics; Primary motor cortex; Presenilin-1 mutation; Pyramidal signs; Tetraspasticity; Early-onset familial Alzheimer’s disease; Motor dysfunction; Human; Nervous system diseases; Alzheimer disease; Presenilin; Cerebral disorder; Familial disease; Central nervous system disease; Early; Degenerative disease; Mutation; Early-onset familial Alzheimer's disease
• ISSN: 0197-4580; 1558-1497
• DOI: 10.1016/S0197-4580(02)00192-6

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 Aβ
1–40 and Aβ
1–42, 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.