Two novel (M233T and R278T) presenilin-1 mutations in early-onset Alzheimer's disease pedigrees and preliminary evidence for association of presenilin-1 mutations with a novel phenotype. NeuroReport 8:1537-1542

Garvan Institute of Medical Research, Sydney, NSW, Australia.
Neuroreport (Impact Factor: 1.64). 05/1997; 8(6):1537-42.
Source: PubMed

ABSTRACT Eleven early-onset dementia families, all with affected individuals who have either presented clinical symptoms of early onset familial Alzheimer's disease (EOFAD) or have been confirmed to have EOFAD by autopsy, and two early onset cases with biopsy-confirmed AD pathology, were screened for missense mutations in the entire coding region of presenilin-1 (PS-1) and -2 (PS-2) genes. Missense mutations were detected by direct sequence analysis of PCR products amplified from genomic DNA templates of affected individuals. Three pedigrees were attributable to known mutations in the PS-1 gene: P264L, E280A and the splice acceptor site (G to T) mutation, which results in the deletion of residues 290-319 of PS-1 (PS-1 delta 290-319). In a fourth pedigree, a novel PS-1 mutation was identified in exon 7 (M233T), which is homologous to a pathogenic PS-2 mutation (M239V), and is characterized by a very early average age of onset (before the age of 35). In one early onset case, another novel PS-1 mutation was identified in exon 8 (R278T). Of the five remaining families and the other early onset case, none have missense mutations in the PS-1 or PS-2 genes, or in exon 16 and 17 of the APP gene. Moreover, two of the PS-1 mutations, PS-1 delta 290-319 and R278T, are associated with the co-presentation of familial spastic paraparesis (FSP) in some of the affected family members. Our data raise the possibility that the phenotypic spectrum associated with PS-1 mutations may extend beyond typical FAD to include FSP, a disease heretofore unsuspected to bear any relationship to FAD. In addition, our data suggest that other novel EOFAD loci, in addition to APP and the presenilin genes, are involved in the aetiology of up to 50% of EOFAD cases.

  • Source
    • "Colombian kindred 28 Onset 49.01 (6.08) – – 1997 [27] PS1 E280A genealogy in Australia 1 Onset 47 – – 1997 [25] "
    [Show abstract] [Hide abstract]
    ABSTRACT: Presenilin 1 (PS1) mutations are the most common cause of early-onset familial Alzheimer's disease (EOFAD). They show a common phenotypic profile characterized by early age of onset, severe dementia and distinct neurodegeneration. The largest population of EOFAD carries the E280A mutation in PS1 and resides in Antioquia, Colombia, currently comprising around 5,000 individuals. Carriers start showing memory impairment in the third decade of life, followed by progressive impairment of language and other cognitive processes. They reach mild cognitive impairment around 45 and dementia around 50 years of age. There is some phenotypic variability among the carriers of this single PS1 mutation. Some patients present with epilepsy, verbal impairment, and cerebellar ataxia. Neuropathologically, PS1 E280A cases show pronounced brain atrophy, severe amyloid-β pathology, distinct hyperphosphorylated tau-related pathology, and cerebellar damage. The earliest event identified by functional magnetic imaging resonance is hyperactivation within the right anterior hippocampus around 33 years of age. This well-studied population with a clear pre-clinical profile and wide phenotypic variability in age of onset and clinical presentation is ideally suited for clinical trials and to study molecular mechanisms of Alzheimer's disease.
    Journal of Alzheimer's disease: JAD 07/2012; 32(1):1-12. DOI:10.3233/JAD-2012-120907 · 4.15 Impact Factor
  • Source
    • "twenties ( Taddei et al . 1998 ) . At age 34 , the patient had a moderate dementia , abnormal gait , and brisk reflexes with bilateral extensor plantar responses , although tone was normal . As the dementia progressed , the patient became physically more disabled with increasing spasticity , pseudobulbar palsy and rigidity , and died at 40 years ( Kwok et al . 1997 ; Taddei et al . 1998 ) . Since these reports , other PSEN1 mutations in AD / SP pedigrees have been reported , in particular in patients with PSEN1 exon 9 deletions . Known AD / SP pedigrees are described below and reviewed in further detail by Karlstrom et al . 2005 and summarized in Table 2 ."
    [Show abstract] [Hide abstract]
    ABSTRACT: Pedigrees with familial Alzheimer’s disease (AD) show considerable phenotypic variability. Spastic paraparesis (SP), or progressive spasticity of the lower limbs is frequently hereditary and exists either as uncomplicated (paraparesis alone) or complicated (paraparesis and other neurological features) disease subtypes. In some AD families, with presenilin-1 (PSEN1) mutations, affected individuals also have SP. These PSEN1 AD pedigrees frequently have a distinctive and variant neuropathology, namely large, non-cored plaques without neuritic dystrophy called cotton wool plaques (CWP). The PSEN1 AD mutations giving rise to CWP produce unusually high levels of the amyloid β peptide (Aβ) ending at position 42 or 43, and the main component of CWP is amino-terminally truncated forms of amyloid β peptide starting after the alternative β-secretase cleavage site at position 11. This suggests a molecular basis for the formation of CWP and an association with both SP and AD. The SP phenotype in some PSEN1 AD pedigrees also appears to be associated with a delayed onset of dementia compared with affected individuals who present with dementia only, suggesting the existence of a protective factor in some individuals with SP. Variations in neuropathology and neurological symptoms in PSEN1 AD raise the prospect that modifier genes may underlie this phenotypic heterogeneity.
    Journal of Neurochemistry 03/2008; 104(3):573-83. DOI:10.1111/j.1471-4159.2007.05038.x · 4.24 Impact Factor
  • Source
    • "Frozen tissue for Western blot analysis from four sporadic AD, eight PS-1 AD, five young and three aged control brains was also available. Four PS-1 cases were due to deletions in exon 9 [7], two cases were siblings from a pedigree with a M146L mutation [53], one case had a P264L mutation [19] and one had a S169L mutation [55]. A summary of case details for groups including sex, age at death, postmortem delay and disease duration is presented in Table 1. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Inflammation, insoluble protein deposition and neuronal cell loss are important features of the Alzheimer's disease (AD) brain. S100B is associated with the neuropathological hallmarks of AD where it is thought to play a role in neuritic pathology. S100A8, S100A9 and S100A12 comprise a new group of inflammation-associated proteins that are constitutively expressed by neutrophils and inducible in numerous inflammatory cells. We investigated expression of S100B, S100A8, S100A9 and S100A12 in brain samples from sporadic and familial (PS-1) AD cases and controls using immunohistochemistry and Western blot analysis. S100B, S100A9 and S100A12, but not S100A8, were consistently associated with the neuropathological hallmarks of AD. Western blot analysis confirmed significant increases in soluble S100A9 in PS-1 AD compared to controls. S100A9 complexes that were resistant to reduction were also evident in brain extracts. A reactive component of a size consistent with hexameric S100A12 was seen in all cases. This study indicates a potential role for pro-inflammatory S100A9 and S100A12 in pathogenesis caused by inflammation and protein complex formation in AD.
    Neurobiology of aging 12/2006; 27(11):1554-63. DOI:10.1016/j.neurobiolaging.2005.09.033 · 4.85 Impact Factor
Show more