Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and Alzheimer's disease.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a ubiquitous enzyme that catalyzes the sixth step of glycolysis and thus, serves to break down glucose for energy production. Beyond the traditional aerobic metabolism of glucose, recent studies have highlighted additional roles played by GAPDH in non-metabolic processes, such as control of gene expression and redox post-translational modifications. Neuroproteomics have revealed high affinity interactions between GAPDH and Alzheimer's disease-associated proteins, including the ß-amyloid, ß-amyloid precursor protein and tau. This neuronal protein interaction may lead to impairment of the GAPDH glycolytic function in Alzheimer's disease and may be a forerunner of its participation in apoptosis. The present review examines the crucial implication of GAPDH in neurodegenerative processes and clarifies its role in apoptotic cell death.

[Clinical presentation of Moroccan cases with Alzheimer's disease]. / Présentation clinique de cas marocains atteints de la maladie d'Alzheimer.

INTRODUCTION: The diagnostic approach for Alzheimer's disease is based on the presence of cerebral atrophy combined with the score of the mini-examination of the mental state. In this context, this study was conducted to assess the correlation between imaging and neuropsychological testing for cases of early-onset and late-onset Alzheimer's disease. AIM OF THE STUDY: Analysis of the clinical and paraclinical aspects of Moroccan cases with Alzheimer's disease. METHODS: Seventeen sporadic cases and 8 family cases were seen at the memory clinic of the Neurology Department of the University of Casablanca Ibn Rochd Hospital. A family history was obtained through a clinical interview of the patient and a yes or no self-reporting questionnaire from the guardian or other family member. The disease was considered familial if at least one additional first degree relative suffered from early-onset AD-type dementia. All patients underwent standard somatic neurological examination, cognitive function assessment, brain imaging and laboratory tests. Written consent was obtained from the patients and their guardians prior to the study. RESULTS: In our study of 25 individuals, the observed mean age of AD patients was 64.52 ± 9.30 and we observed a slight female predominance (56% versus 44%). In addition, we found a prevalence of AD of approximately 20%, increasing with age, in the population below 60 years of age. Approximately half of our patients (48%) had a score lower than 10 and were affected by severe insanity, while 28% were affected by moderate severe insanity and 24% were light to moderately insane. Twenty-five patients underwent neuroimaging, 18 of whom were assessed by MRI, while 7 were assessed by CT. All patients had hippocampal atrophy, which progressed to affect others brain regions. The blood tests showed no abnormalities in the 25 enrolled AD cases. DISCUSSION: Age is undoubtedly the main risk factor for AD; this is also the true for our cases where advanced age was responsible for the exponential increase of the disease's frequency; it reached a peak in the age group of 60-69 years. The AD diagnosis approach is based on the presence of cerebral atrophy combined with the score of the mini-examination of the mental state (MMSE). In our study, in addition to the MMSE, depending on the level of education, the clinician used other tests that do not necessarily require a level of education such as the BEC96, visual short-term or digital memory assessment, work memory assessment, language assessment test (DO80) and apraxia. Neuropsychological examination of the cases with a score of less than 10 showed severe cognitive impairment. The cases presented memory and language impairments, aphasia, visual spatial disorientation, decreased autonomy, executive dysfunction and praxis deficits, all major causes of severe dementia. Neuroimaging revealed hippocampal and cortical atrophy. Correlated with the other studies that aimed to establish links between brain alterations and neuropsychological disorders, we can conclude that a higher level of atrophy reflects a decrease in neuropsychological performance.

Novel presenilin mutations within Moroccan patients with Early-Onset Alzheimer's Disease.

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-year-old 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, AD is caused by a mutation in one of at least 3 genes: presenilin 1 (PS1), presenilin 2 (PS2) and the 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 AD and predicting disease incidence remain elusive. The purpose of the present study was to evaluate the genetic contribution of mutations in 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.

[Genetic aspects of Alzheimer's disease (Review)]. / Les aspects génétiques de la maladie d'Alzheimer (Revue).

Alzheimer's disease is a degenerative brain disorder, which concerns memory, cognition and behavior pattern. Its etiology is unknown, it is characterized by typical histological lesions: senile plaques and neuro-fibrillary tangles. Alzheimer's disease is a multifactorial pathology, characterized by interactions between genetic and environmental factors. Genetic factors concern first of all the exceptional monogenic forms, characterized by early onset (<60 years), autosomal dominant forms. Mutations of the genes coding for amyloid-ß precursor protein or preselinins 1 and 2 are involved. The much more frequent sporadic forms also have genetic factors, the best studied being the apolipoprotein E4 coding allele and some more recent genotypes which will be mentioned. No causal, only symptomatic treatments are available.