A presenilin 1 R278I mutation presenting with language impairment
ABSTRACT Presenilin (PSEN)1 mutations are responsible for many cases of autosomal dominant Alzheimer disease (AD), although the clinical spectrum has not been fully defined. The authors describe two members of a kindred with a novel PSEN1 mutation (R278I) presenting with language impairment and relative preservation of memory. Screening for PSEN1 mutations may be appropriate in cases of familial dementia even where the clinical phenotype is not typical of AD.
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ABSTRACT: Alzheimer's disease (AD) is a progressive brain disorder that causes gradual and irreversible loss of higher brain functions and is the most common cause of dementia in the elderly,, as assessed by autopsy and clinical series. Furthermore, it has an annual incidence of approximately 3% in the 65-74 age group. This incidence rate doubles with every increment of 5 years above the age of 65. In Morocco, AD affects almost 30,000 individuals and this number will possibly increase to 75,000 by 2020 (projections of the World Health Organization (WHO)). Genetically, Alzheimer disease is caused by a mutation in one of at least 3 genes: presenilin 1 (PS1), presenilin 2 (PS2) and amyloid precursor protein(APP). Most cases are late onset and apparently sporadic, most likely as a result of a combination of environmental and non-dominant genetic factors. In Morocco, the genes predisposing individuals to Alzheimer's disease (AD) and predicting disease incidence remain elusive. The purpose of the present study was to evaluate the genetic contribution of mutations in the PS1 and PS2 genes to familial early-onset AD cases and sporadic late-onset AD cases. Seventeen sporadic late-onset AD cases and eight familial early-onset AD cases were seen at the memory clinic of the University of Casablanca Neurology Department. These patients underwent standard somatic neurological examination, cognitive function assessment, brain imaging and laboratory tests. Direct sequencing of each exon in PS1 and PS2 genes was performed on genomic DNA of AD patients. Further, we identified 1 novel frameshift mutation in the PS1 gene and 2 novel frameshift mutations in the PS2 gene. Our mutational analysis reports a correlation between clinical symptoms and genetic factors in our cases of Early Onset Alzheimer's Disease (EOAD). These putative mutations cosegregate with affected family members suggesting a direct mutagenic effect.Neuroscience 04/2014; 269. DOI:10.1016/j.neuroscience.2014.03.052 · 3.33 Impact Factor
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ABSTRACT: Primary progressive aphasia (PPA) represents a diverse group of language-led dementias most often due to frontotemporal lobar degeneration. We report clinical, neuropsychological, and neuroimaging data in the case of a 47-year-old woman presenting with non-fluent PPA due to a genetically confirmed pathogenic Presenilin 1 P264L mutation. This case highlights an unusual clinical presentation of familial Alzheimer's disease and a novel presentation of the P264L mutation. The case adds to accumulating evidence that particular mutations can promote specific brain network degeneration, with wider implications for understanding the sporadic forms of Alzheimer's disease and PPA.Journal of Alzheimer's disease: JAD 04/2013; 36(2). DOI:10.3233/JAD-122092 · 3.61 Impact Factor
Article: The genetics of Alzheimer’s disease[Show abstract] [Hide abstract]
ABSTRACT: Alzheimer's disease (AD) is a complex and heterogeneous neurodegenerative disorder, classified as either early onset (under 65 years of age), or late onset (over 65 years of age). Three main genes are involved in early onset AD: amyloid precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2). The apolipoprotein E (APOE) E4 allele has been found to be a main risk factor for late-onset Alzheimer's disease. Additionally, genome-wide association studies (GWASs) have identified several genes that might be potential risk factors for AD, including clusterin (CLU), complement receptor 1 (CR1), phosphatidylinositol binding clathrin assembly protein (PICALM), and sortilin-related receptor (SORL1). Recent studies have discovered additional novel genes that might be involved in late-onset AD, such as triggering receptor expressed on myeloid cells 2 (TREM2) and cluster of differentiation 33 (CD33). Identification of new AD-related genes is important for better understanding of the pathomechanisms leading to neurodegeneration. Since the differential diagnoses of neurodegenerative disorders are difficult, especially in the early stages, genetic testing is essential for diagnostic processes. Next-generation sequencing studies have been successfully used for detecting mutations, monitoring the epigenetic changes, and analyzing transcriptomes. These studies may be a promising approach toward understanding the complete genetic mechanisms of diverse genetic disorders such as AD.Clinical Interventions in Aging 04/2014; 9:535-551. DOI:10.2147/CIA.S51571 · 1.82 Impact Factor