Corticobasal Degeneration (CBD) is a heterogeneous neurodegenerative disorder characterized by asymmetric parkinsonism, apraxia, cortical sensory loss, and alien limb phenomena. Pathologically, CBD is characterized by tau-positive inclusions in [neurons](/entities/neurons) and glia, with 4R tau isoforms predominating. Genetic studies have identified MAPT (microtubule-associated protein tau) as the major genetic contributor to CBD risk, with the H1 haplotype being the primary risk factor and specific mutations causing familial cases.
Overview
CBD shows significant clinical and pathological overlap with other tauopathies:
MAPT H1 haplotype: Major risk factor[@genotypephenotype]
Specific MAPT mutations: Cause familial CBD presentations[@medical]
Overlap genes: Shared risk with PSP, FTLD-Tau, and PD
Other genes: Reported associations with DCTN, TGM6
Major Genetic Variants
MAPT H1 Haplotype
The MAPT H1 haplotype is strongly associated with CBD:
Prevalence: >95% of CBD patients carry H1/H1 genotype
Risk: H1/H1 increases CBD risk by 3-8 fold
Mechanism: Altered tau isoform expression (increased 4R tau)
The H1 haplotype encompasses multiple risk SNPs:
rs242557
rs1800547
rs2471738
MAPT Mutations in CBD
Several MAPT mutations cause CBD or CBD-like phenotypes:
P301L Mutation
The most well-known mutation causing CBD phenotypes:
...
CBD Genetic Variants
Introduction
Corticobasal Degeneration (CBD) is a heterogeneous neurodegenerative disorder characterized by asymmetric parkinsonism, apraxia, cortical sensory loss, and alien limb phenomena. Pathologically, CBD is characterized by tau-positive inclusions in [neurons](/entities/neurons) and glia, with 4R tau isoforms predominating. Genetic studies have identified MAPT (microtubule-associated protein tau) as the major genetic contributor to CBD risk, with the H1 haplotype being the primary risk factor and specific mutations causing familial cases.
Overview
CBD shows significant clinical and pathological overlap with other tauopathies:
MAPT H1 haplotype: Major risk factor[@genotypephenotype]
Specific MAPT mutations: Cause familial CBD presentations[@medical]
Overlap genes: Shared risk with PSP, FTLD-Tau, and PD
Other genes: Reported associations with DCTN, TGM6
Major Genetic Variants
MAPT H1 Haplotype
The MAPT H1 haplotype is strongly associated with CBD:
Prevalence: >95% of CBD patients carry H1/H1 genotype
Risk: H1/H1 increases CBD risk by 3-8 fold
Mechanism: Altered tau isoform expression (increased 4R tau)
The H1 haplotype encompasses multiple risk SNPs:
rs242557
rs1800547
rs2471738
MAPT Mutations in CBD
Several MAPT mutations cause CBD or CBD-like phenotypes:
P301L Mutation
The most well-known mutation causing CBD phenotypes:
Inheritance: Autosomal dominant
Penetrance: ~90% by age 65
Phenotype: Classic CBD with prominent cortical symptoms
Mechanism: Promotes tau aggregation, reduces microtubule binding
P301S Mutation
Reported in families with CBD features:
Phenotype: Progressive aphasia and parkinsonism
Mechanism: Similar to P301L
ΔN296 (Exon 10 Splicing)
Affects alternative splicing of exon 10:
Effect: Increases 4R tau isoform
Phenotype: CBD or PSP phenotype
R5L and Other Variants
R5L: Rare variant associated with CBD in some families
K369I: Reported in families with CBD features
S305I: Affects exon 10 splicing
DCTN (Dynactin) Variants
DCTN encodes the p150 subunit of dynactin, involved in axonal transport:
Common variant: p.G59D (autosomal dominant)
Phenotype: Lower limb-onset parkinsonism with CBD features
The study of Cbd Genetic Variants has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
External Links
[PubMed](https://pubmed.ncbi.nlm.nih.gov/) - Biomedical literature
[Alzheimer's Disease Neuroimaging Initiative](https://adni.loni.usc.edu/) - Research data
[Allen Brain Atlas](https://brain-map.org/) - Brain gene expression data
[Clinical Trials for CBD](/therapeutics/cbs-psp-clinical-trials-guide) — Trial information
Research Resources
[CBD Investment Landscape](/investment/corticobasal_degeneration) — Research funding
Recent Research (2024-2026)
This section highlights recent publications relevant to this disease.
[Adjunctive cannabidiol in intractable pediatric epilepsy: A retrospective study on tolerability, efficacy, and safety across genetic and nongenetic etiologies.](https://pubmed.ncbi.nlm.nih.gov/41630268/) (2026 Jan 30) - Medicine
[Genotype-Phenotype Correlations of COL2A1 and COL11A1 Patients.](https://pubmed.ncbi.nlm.nih.gov/40930209/) (2026 Jan) - American journal of ophthalmology
[Medical Marijuana and Treatment Personalization: The Role of Genetics and Epigenetics in Response to THC and CBD.](https://pubmed.ncbi.nlm.nih.gov/41465160/) (2025 Dec 12) - Genes
[Genome-wide association study and HLA genotyping for beryllium disease susceptibility in a European descent population.](https://pubmed.ncbi.nlm.nih.gov/41075949/) (2025 Nov 5) - Gene
[Population-scale gene-based analysis of whole-genome sequencing provides insights into metabolic health.](https://pubmed.ncbi.nlm.nih.gov/41073786/) (2025 Oct) - Nature genetics