Clinical presentation of early-onset Alzheimer's disease as a result of mutation in exon 12 of the PSEN-1 gene

Early-Onset Alzheimer's Disease Masquerading as Catatonia

A 35-year-old woman with a history of sexual trauma was brought in by her family for further evaluation of depressive symptoms and progressive decline in activities of daily living. She was admitted to the inpatient psychiatric unit for the treatment of suspected catatonia. After failure to respond to standard medical treatment, she received an extensive workup, which ultimately revealed a PSEN1 mutation consistent with early-onset Alzheimer's disease. Diagnosis was challenging because of her young age, lack of reliable family history, and reports of recent sexual abuse by her biological father. This case is a cautionary reminder for clinicians that end stages of dementia can present similar to catatonia with mutism, lack of spontaneous movement, and refusal to eat. The clues to the diagnosis were profound cortical atrophy and lack of improvement with optimal medical management.

A Clinical Case of Patient Carrying Rare Pathological PSEN1 Gene Mutation (L424V) Demonstrates the Phenotypic Heterogenity of Early Onset Familial AD

Dementia comprises several neurodegenerative disorders with similar neuropsychiatric features and Alzheimer's disease (AD) is the most common of them. Genetic factors are strongly implicated into its etiology especially for early-onset cases (EOAD) occuring before the age of 65. About 10% of these are inherited in autosomal dominant fashion via pathogenic polymorphisms in three genes- APP, PSEN-1, and PSEN-2. Despite genotypic clarity, however, phenotypic variability exists with different symptom constellations observed in patients with identical mutations. Below, we present a case of a 39-year-old male with a family history for early onset dementia who was referred to our department with anamnesis for abrupt behavioral change 7 months prior to hospitalization-noticeable slowing of speech and reactivity, impaired occupational functioning and irritability, followed by aphasic symptoms and transient episodes of disorientation. He was followed up for 2 years and manifested rapidly progressing cognitive decline with further deterioration of speech, apraxia, acalculia, ataxia, and subsequently bradykinesia and tremor. Based on the clinical and neuroimaging findings (severe cortical atrophy), familial EOAD was suspected and a whole exome sequence (WES) analysis was performed. It identified a heterozygous missense variant Leu424Val (g.71074C > G) in PSEN-1 gene considered to be pathogenic, and only reported once until now in a Spanish patient in 2009. Despite genotype identity however, distinct phenotypic presentations were observed in the two affected subjects, with different neuroimaging findings, and the presence and absence of seizures in the Spanish and Bulgarian case, respectively. Besides, myoclonus and spastic paraparesis considered "typical" EOAD clinical features were absent. Age of symptom onset was consistent with two of the reported mutations affecting 424 codon of PSEN-1 gene and significantly earlier than the other two implying that factors influencing activity of PSEN-1 pathological forms are yet to be clarified. Furthermore, our patient had co-occurring lupus erythematosus (LE) and we suggest that this condition might be etiologically linked to the PSEN-1 mutation. In addition to illustrating the symptomatic heterogeneity of PSEN-1 caused EOAD, our study confirms that in patients presenting with early cognitive deterioration and family history for dementia, WES can be especially informative and should be considered as a first-line examination.

Perspectives of General Practitioners on the Issues Surrounding the Late Diagnosis of Alzheimer's Disease

We set out to investigate the insights general practitioners (GPs) have into the early signs and symptoms of Alzheimer's disease (AD), factors that may be responsible for the late diagnosis, as well as their recommendations for early diagnosis of AD. This was a semi-structured, qualitative and audio-recorded interview of seven GPs, from five GP surgeries in Milton Keynes and Luton, using the framework analysis. GPs reported challenges with the current patient's consultation time, a lack of continuity of care, inadequate training, limited support for patients after diagnosis, and poor treatment of the UK's aging population. The study highlights important changes that would facilitate the earlier diagnosis of AD.

Mitochondrial Biology and Neurological Diseases

Mitochondria are extremely active organelles that perform a variety of roles in the cell including energy production, regulation of calcium homeostasis, apoptosis, and population maintenance through fission and fusion. Mitochondrial dysfunction in the form of oxidative stress and mutations can contribute to the pathogenesis of various neurodegenerative diseases such as Parkinson’s (PD), Alzheimer’s (AD), and Huntington’s diseases (HD). Abnormalities of Complex I function in the electron transport chain have been implicated in some neurodegenerative diseases, inhibiting ATP production and generating reactive oxygen species that can cause major damage to mitochondria

Mutations in both nuclear and mitochondrial DNA can contribute to neurodegenerative disease, although the pathogenesis of these conditions tends to focus on nuclear mutations. In PD, nuclear genome mutations in the PINK1 and parkin genes have been implicated in neurodegeneration [1], while mutations in APP, PSEN1 and PSEN2 have been implicated in a variety of clinical symptoms of AD [5]. Mutant htt protein is known to cause HD [2]. Much progress has been made to determine some causes of these neurodegenerative diseases, though permanent treatments have yet to be developed. In this review, we discuss the roles of mitochondrial dysfunction in the pathogenesis of these diseases.

Probable novel PSEN2 Pro123Leu mutation in a Chinese Han family of Alzheimer's disease

We describe a probably novel mutation in exon 5 of the presenilin 2 gene (Pro123Leu) in a Chinese familial early-onset Alzheimer's disease, which clinically manifests as progressive memory loss, cognitive impairment, parkinsonism, and myoclonic jerks. Clinical and neuroimaging examination, target region capture, and high-throughput sequencing were performed in a family of 4 generations. Cerebral perfusion and glucose metabolism were evaluated using arterial spin labeling perfusion magnetic resonance imaging and (18)F-fludeoxyglucose positron emission tomography, respectively. Target region capture sequencing yielded a novel missense mutation at codon 123 (P123L) which is a heterozygous C to T point mutation at position 368 (c.368C>T) in exon 5 of the presenilin 2 leading to a proline-to-leucine substitution. The results were also identified by Sanger sequencing in 7 family members but not in the other 9 unaffected family members and 100 control subjects. This mutation is probably pathogenic and is the first of its kind reported in an early-onset familial AD associated with atypical symptom presentation.