Diseases Overview

Diseases Overview

Overview

Diseases Overview is a condition with relevance to the neurodegenerative disease landscape. This page covers its molecular basis, clinical features, genetic associations, and connections to broader neurodegeneration research.

This section contains comprehensive information on neurodegenerative diseases, covering Alzheimer's disease, Parkinson's disease, ALS, frontotemporal dementia, and related disorders. These conditions share common features including progressive neuronal loss, protein aggregation, and eventual cognitive and motor impairment.[@gitler2018]

Major Disease Categories

Alzheimer's Disease and Related Dementias

Alzheimer's disease (AD) is the most common neurodegenerative disease, affecting an estimated 6.5 million Americans aged 65 and older.[@alzheimers2023] The disease is characterized by extracellular [amyloid-beta](/proteins/amyloid-beta) (Aβ) plaques and intracellular neurofibrillary tangles composed of hyperphosphorylated [tau protein](/proteins/tau). Cognitive decline typically begins with episodic memory impairment and progresses to include language deficits, visuospatial dysfunction, and behavioral changes.[@scheltens2021]

Diseases Overview

Overview

Diseases Overview is a condition with relevance to the neurodegenerative disease landscape. This page covers its molecular basis, clinical features, genetic associations, and connections to broader neurodegeneration research.

This section contains comprehensive information on neurodegenerative diseases, covering Alzheimer's disease, Parkinson's disease, ALS, frontotemporal dementia, and related disorders. These conditions share common features including progressive neuronal loss, protein aggregation, and eventual cognitive and motor impairment.[@gitler2018]

Major Disease Categories

Alzheimer's Disease and Related Dementias

Alzheimer's disease (AD) is the most common neurodegenerative disease, affecting an estimated 6.5 million Americans aged 65 and older.[@alzheimers2023] The disease is characterized by extracellular [amyloid-beta](/proteins/amyloid-beta) (Aβ) plaques and intracellular neurofibrillary tangles composed of hyperphosphorylated [tau protein](/proteins/tau). Cognitive decline typically begins with episodic memory impairment and progresses to include language deficits, visuospatial dysfunction, and behavioral changes.[@scheltens2021]

• [Alzheimer's Disease (AD)](/diseases/alzheimers-disease) — Comprehensive disease overview
• [Alzheimer's Disease Genetics](/diseases/alzheimers-disease-genetics) — Genetic risk factors including [APOE](/proteins/apoe), [APP](/entities/app-protein), [PSEN1](/entities/psen1), [PSEN2](/entities/psen2)
• [Alzheimer's Disease Treatments](/diseases/alzheimers-disease-treatments) — Current and emerging therapeutic approaches
• [Mild Cognitive Impairment (MCI)](/diseases/mild-cognitive-impairment) — Often a prodromal stage of AD
• [Lewy Body Dementia](/diseases/lewy-body-dementia) — Second most common dementia type

Parkinson's Disease and Movement Disorders

Parkinson's disease (PD) is the second most common neurodegenerative disease, affecting approximately 1 million Americans.[@parkinsons] The hallmark pathological features are Lewy bodies (intracellular inclusions rich in alpha-synuclein) and loss of dopaminergic [neurons](/entities/neurons) in the substantia nigra pars compacta. Motor symptoms include resting tremor, bradykinesia, rigidity, and postural instability.[@kalia2015]

• [Parkinson's Disease (PD)](/diseases/parkinsons-disease) — Comprehensive disease overview
• [Parkinson's Disease Genetics](/diseases/parkinsons-disease-genetics) — Genetic factors including [LRRK2](/entities/lrrk2), [GBA](/entities/gba), SNCA, PARK2
• [Parkinson's Disease Treatments](/diseases/parkinsons-disease-treatments) — Dopaminergic therapies and emerging disease-modifying treatments
• [Parkinson's Disease with Dementia](/diseases/parkinsons-disease-dementia) — Cognitive impairment in PD

Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive motor neuron disease affecting both upper and lower motor neurons. Most cases are sporadic, while approximately 10-20% are familial. The disease leads to progressive muscle weakness, respiratory failure, and typically death within 2-5 years of onset.[@hardiman2017]

• [ALS](/diseases/als) — Comprehensive disease overview
• [ALS Genetics](/diseases/als-genetic-variants) — Major genetic causes: [C9orf72](/entities/c9orf72), SOD1, FUS, TARDBP
• [ALS Treatments](/diseases/als-treatments) — Current approved therapies (riluzole, edaravone) and clinical trials
• [ALS-FTD Spectrum](/diseases/als-ftd-spectrum) — Overlap between ALS and frontotemporal dementia

Frontotemporal Dementia

Frontotemporal dementia (FTD) encompasses a spectrum of disorders characterized by progressive degeneration of the frontal and temporal lobes. The behavioral variant FTD presents with personality changes and social conduct deficits, while primary progressive aphasia affects language function.[@rascovsky2011]

• [Frontotemporal Dementia (FTD)](/diseases/frontotemporal-dementia) — Comprehensive disease overview
• [FTD Genetics](/diseases/ftd-genetic-variants) — Major genetic causes: GRN, MAPT, C9orf72
• [Pick's Disease](/pick's-disease) — FTD subtype with tau pathology

Other Neurodegenerative Diseases

• [Huntington's Disease](/diseases/huntington-disease) — Autosomal dominant disorder caused by CAG repeat expansion in the HTT gene
• [Multiple System Atrophy (MSA)]('/diseases/multiple-system-atrophy) — Alpha-synucleinopathy affecting autonomic nuclei and cerebellum
• [Progressive Supranuclear Palsy (PSP)]('/diseases/progressive-supranuclear-palsy) — Tauopathy with vertical gaze palsy
• [Corticobasal Degeneration (CBD)]('/diseases/corticobasal-degeneration) — Tauopathy with asymmetric cortical and basal ganglia involvement
• [Creutzfeldt-Jakob Disease](/diseases/creutzfeldt-jakob) — Prion disease with rapid progression

Disease Classification Framework

Neurodegenerative diseases can be classified by their characteristic protein aggregates:

| Proteinopathy | Associated Diseases |
|---------------|---------------------|
| Amyloid-beta | Alzheimer's disease |
| Tau | AD, PSP, CBD, Pick's disease |
| [Alpha-synuclein](/proteins/alpha-synuclein) | PD, MSA, Lewy body dementia |
| [TDP-43](/mechanisms/tdp-43-proteinopathy) | ALS, FTD |
| FUS | ALS, FTD |
| [Huntingtin](/proteins/huntingtin) | Huntington's disease |
| Prion protein | CJD, fatal insomnia |

Epidemiology and Impact

Neurodegenerative diseases represent a growing public health challenge due to aging populations worldwide:[@gbd2019]

• Alzheimer's disease affects 6.5 million Americans (2023), projected to reach 12.7 million by 2050
• Parkinson's disease affects 1 million Americans, with 90,000 new diagnoses annually
• ALS has a prevalence of approximately 30,000 in the US, with 5,000 new cases yearly
• Frontotemporal dementia affects 50,000-60,000 Americans

Shared Mechanisms

While each disease has distinct features, common pathogenic mechanisms include:[@duggan2021]

• Protein misfolding and aggregation — Formation of toxic oligomers and insoluble deposits
• Proteostasis failure — Impaired protein quality control systems
• Mitochondrial dysfunction — Energy depletion and oxidative stress
• Neuroinflammation — Chronic activation of [microglia](/cell-types/microglia-neuroinflammation) and [astrocytes](/entities/astrocytes)
• Synaptic dysfunction — Loss of synaptic connections and plasticity
• Axonal transport defects — Impaired trafficking of cellular components
• Cellular senescence — Accumulation of senescent cells in the brain

Research Focus Areas

• [Biomarkers](/biomarkers/) — Disease diagnosis and progression markers
• [Genes](/entities/) — Disease-associated genetic variants
• [Mechanisms](/mechanisms/) — Molecular pathways involved in neurodegeneration
• [Treatments](/treatments/) — Therapeutic approaches and clinical trials
• [Clinical Trials](/clinical-trials/) — Active and completed trials

Key Resources

• [Disease Rankings](/diseases/rankings) — Ranked list of neurodegenerative diseases by research activity
• [Disease Prevalence](/diseases/disease-prevalence) — Epidemiology data
• [Disease Classification](/diseases/disease-classification) — Taxonomic relationships

See Also

• [Alzheimer's Disease (AD)](/diseases/alzheimers-disease)
• [Alzheimer's Disease Genetics](/diseases/alzheimers-disease-genetics)
• [Alzheimer's Disease Treatments](/diseases/alzheimers-disease-treatments)
• [Mild Cognitive Impairment (MCI)](/diseases/mild-cognitive-impairment)
• [Lewy Body Dementia](/diseases/lewy-body-dementia)
• [Parkinson's Disease (PD)](/diseases/parkinsons-disease)
• [Parkinson's Disease Genetics](/diseases/parkinsons-disease-genetics)
• [Parkinson's Disease Treatments](/diseases/parkinsons-disease-treatments)
• [Parkinson's Disease with Dementia](/diseases/parkinsons-disease-dementia)
• [ALS](/diseases/als)

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
• [KEGG Pathways](https://www.genome.jp/kegg/pathway.html)

Topics

• [Diseases Overview](/diseases/overview) — This page
• [Diseases Rankings](/diseases/rankings) — Ranked list by research activity
• [Diseases Dashboard](/diseases/dashboard) — Data visualizations and metrics

Summary Statistics

• Total Pages: 374 Diseases pages in this section
• Last Updated: This section is actively maintained

A-Z All Pages

• [ALS Progression Rate Heterogeneity](/diseases/als-progression-rate-heterogeneity)
• [ALS-FTD Spectrum](/diseases/als-ftd-spectrum)
• [APOE2 (Apolipoprotein E2)](/diseases/apoe2)
• [APOE3 (Apolipoprotein E3)](/diseases/apoe3)
• [APOE4 (Apolipoprotein E4)](/diseases/apoe4)
• [APP Arctic Mutation (APP Arctic)](/diseases/app-arctic-mutation)
• [APP Dutch Mutation (APP Dutch)](/diseases/app-dutch-mutation)
• [APP Flemish Mutation (APP Flemish)](/diseases/app-flemish-mutation)
• [APP Mutations in Alzheimer's Disease](/diseases/app-mutations-in-ad)
• [APP Swedish Mutation (APPswe)](/diseases/app-swedish-mutation)
• [ATP13A9 and Parkinson's Disease](/diseases/atp13a9-pd)
• [Abetalipoproteinemia](/diseases/abetalipoproteinemia)
• [Aceruloplasminemia](/diseases/aceruloplasminemia)
• [Adult Polyglucosan Body Disease (APBD)](/diseases/adult-polyglucosan-body-disease)
• [Adult-Onset Leukoencephalopathy with Axonal Spheroids and Pigmented Glia (ALSP)](/diseases/alsp)
• [Aging-Related Tau Astrogliopathy (ARTAG)](/diseases/aging-related-tau-astrogliopathy)
• [Aging-Related Tauopathy (PART)](/diseases/aging-related-tauopathy)
• [Agitation in Alzheimer's Disease](/diseases/agitation-alzheimers)
• [Alexander Disease](/diseases/alexander-disease)
• [Alexander Disease Genetic Variants](/diseases/alexander-disease-genetic-variants)
• [Allan-Herndon-Dudley Syndrome](/diseases/allan-herndon-duffy-syndrome)
• [Alpers-Huttenlocher Syndrome](/diseases/alpers-syndrome)
• [Alpha-Mannosidosis](/diseases/alpha-mannosidosis)
• [Alpha-Synucleinopathies](/diseases/alpha-synucleinopathies)
• [Alzheimer Disease](/diseases/alzheimers-disease)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Alzheimer's Disease Genetic Variants](/diseases/alzheimers-genetic-variants)
• [Amyloid-Related Imaging Abnormalities (ARIA)](/diseases/amyloid-related-imaging-abnormalities-aria)
• [Amyotrophic Lateral Sclerosis (ALS)](/diseases/als)

References

Pathway Diagram

Pathway Diagram

The following diagram shows the key molecular relationships involving Diseases Overview discovered through SciDEX knowledge graph analysis: