Frontotemporal Dementia Risk and Your Genetics

Written by Scott Peeples, BS Biomedical Sciences · ExomeDNA Founder Reviewed by ExomeDNA Editorial Process Last reviewed: 2026-05-29

This page is informational and is for informational purposes only. Consult a healthcare provider for clinical guidance.

Frontotemporal dementia (FTD) is a group of progressive brain disorders characterized by the degeneration of nerve cells in the frontal and temporal lobes — the regions that govern personality, behavior, judgment, and language. Unlike Alzheimer's disease, FTD most commonly affects people between the ages of 45 and 65, making it one of the most common causes of early-onset dementia. Twin and family studies suggest a substantial inherited component, and genome-wide association studies have identified common variant signals near TMEM106B, BTNL2, HLA-DRA, and HLA-DRB5 that are linked to FTD at the population level. This page covers what these genetic signals reveal about FTD biology, how the research is graded, and how to interpret common-variant risk responsibly.

What is frontotemporal dementia?

Frontotemporal dementia (FTD) is a progressive neurological condition in which nerve cells in the frontal and temporal lobes of the brain deteriorate over time. The frontal and temporal regions govern personality, social behavior, executive decision-making, and language. As cell loss progresses, people typically experience changes in behavior, language difficulties, or problems with movement, depending on the clinical subtype.

FTD is not a single disease but an umbrella term for several related conditions. Behavioral variant FTD — the most common subtype — typically presents as personality changes: disinhibition, reduced empathy, compulsive behaviors, or socially inappropriate conduct that can initially resemble a psychiatric condition. Language-variant forms of FTD present as progressive loss of word retrieval, comprehension, or speech fluency. A smaller proportion of people with FTD also develop motor neuron disease, reflecting a biological and genetic overlap with ALS.

Onset before age 65 is a defining characteristic. Prevalence estimates place FTD at roughly 15 to 22 people per 100,000 in mid-life populations, making it substantially less common than late-onset Alzheimer's but a meaningful contributor to early-onset dementia overall. FTD genetics falls into two distinct categories: rare, high-penetrance familial mutations that cause disease directly in affected families, and common genetic variants identified through genome-wide association studies that modestly shift population-level risk. Your ExomeDNA FTD profile captures the common-variant layer only.

The genetics behind frontotemporal dementia

The strongest common-variant signal for FTD risk identified in genome-wide studies sits near TMEM106B on chromosome 7. TMEM106B encodes a transmembrane protein found in lysosomes — the cellular organelles that break down and recycle damaged proteins and cellular waste. Research has linked variants near this locus to TDP-43 protein accumulation, the pathological hallmark of the most prevalent FTD subtype. Studies have associated the TMEM106B locus with FTD risk across multiple independent cohorts, and it has since been implicated in other neurodegenerative conditions as well, suggesting a broader role in how neurons handle protein clearance. (Ferrari et al. 2014)^[1]

TMEM106B is the most consistently replicated common-variant locus in genome-wide studies of frontotemporal dementia, with signals appearing across multiple independent large-cohort studies — making it the highest-confidence common-variant FTD risk gene identified to date.^[1]

A second prominent signal falls near BTNL2, a gene encoding an immunoregulatory protein in the major histocompatibility complex (MHC) region. BTNL2 encodes a butyrophilin-like B7 family member involved in modulating T-cell activation. The broader MHC region, which includes HLA-DRA and HLA-DRB5, is a recurring hotspot for neurological disease GWAS associations — suggesting that immune surveillance and neuroinflammatory processes contribute to FTD susceptibility. The specific mechanisms by which immune-related genetic variants influence FTD biology remain an active research question, but their appearance across multiple neurodegeneration GWAS datasets points to a genuine biological connection.

Additional genes in the FTD common-variant landscape include ATP9B, a predicted lipid transporter involved in phospholipid translocation and endosomal trafficking, and GATA4, a transcription factor associated with cellular stress response and nerve cell survival. CEP131, involved in ciliogenesis and cellular organization, ENTHD2, GFRA2, HLA-DRB9, and MOB3B also appear among candidate signals, reflecting the biologically diverse architecture of common-variant FTD genetics. The presence of multiple independent loci implicating diverse pathways — lysosomal clearance, immune modulation, lipid trafficking, mitotic biology — suggests that FTD's genetic architecture reflects the condition's complexity: different cell types and processes are vulnerable in different ways.

Multiple genome-wide studies of FTD collectively identify common-variant signals spanning lysosomal biology (TMEM106B), immune modulation (BTNL2, HLA-DRA, HLA-DRB5), lipid transport (ATP9B), and cellular stress response pathways — consistent with FTD's multi-pathway biological character.^[1][2][3]

These associations arise from GWAS-level mapping, meaning most represent nearest-gene associations: the statistically strongest common variant near a given gene is implicated, but causal fine-mapping to establish the mechanistically responsible gene and molecular pathway typically requires additional studies beyond the initial GWAS.

What the research says

Research base: Robust. Multiple independent genome-wide association studies conducted across thousands to tens of thousands of participants have established common-variant associations for FTD at the TMEM106B locus and across several MHC-region genes. These signals have been replicated in independent datasets spanning nearly a decade of FTD genetic research. (Ferrari et al. 2014; further replication studies 2014–2021)^{[1][2][3][4][5]}

The genetic architecture of FTD is heterogeneous. Alongside common GWAS variants, a substantial proportion of FTD cases — particularly those with a strong family history — arise from rare, large-effect mutations that fall outside the common-variant GWAS framework. C9orf72 repeat expansions are a well-characterized familial cause of FTD; GRN (progranulin) loss-of-function mutations and MAPT (tau protein) variants are other documented familial forms. These rare mutations are not what common-variant GWAS identifies, and they require separate clinical genetic evaluation.

Polygenic risk scores for FTD are currently best understood as research tools, not clinical screening instruments. The evidence base for the loci themselves is robust, but the variance explained by current common-variant scoring is a modest fraction of total genetic risk. Absolute lifetime risk for FTD — even at elevated ends of the common-variant risk distribution — is substantially lower than for more prevalent conditions like cardiovascular disease. For the full statistical methodology underlying ExomeDNA's polygenic scores, see our methodology page.

How frontotemporal dementia affects you

Frontotemporal dementia changes how a person behaves, relates to others, and communicates — often in ways that are initially more disorienting for family and colleagues than for the person affected. Behavioral variant FTD typically begins with personality and conduct changes: disinhibition, apathy, reduced empathy, compulsive routines, or socially inappropriate behavior. This can be misinterpreted as depression, midlife personality change, or a psychiatric episode before a neurological cause is recognized.

What your ExomeDNA profile captures is common-variant polygenic risk — the statistical accumulation of genetic signals identified in large GWAS datasets. This is not a clinical finding about about individual FTD development. For the overwhelming majority of people carrying common risk variants, FTD will not develop. The absolute lifetime risk for FTD is low relative to many other conditions, and common-variant risk shifting is modest in absolute terms.

The most important distinction for anyone reading this result is between common-variant GWAS signals and rare familial mutations. If multiple first-degree relatives have been affected by early-onset dementia, FTD, or ALS, the clinically informative evaluation involves full genetic testing for high-penetrance mutations — a separate process from DTC polygenic scoring. Common-variant risk profiling and familial genetic testing answer different questions and should not be conflated.

Working with your frontotemporal dementia risk profile

FTD currently has no approved preventive pharmacotherapy targeting the genetic pathways implicated in GWAS. Because common-variant polygenic risk for FTD does not guide clinical management, the actionable framework differs substantially from conditions like cardiovascular disease or type 2 diabetes where lifestyle modification has strong evidence.

What current evidence supports

• Weight family history appropriately. A parent or sibling affected by early-onset dementia or FTD carries more clinical relevance than any common-variant polygenic score. Family history drives clinical decision-making; common-variant risk scores add context but do not replace it.
• Understand the testing landscape. For individuals with a strong family history of FTD or ALS, clinical genetic testing through a neurogenetics specialist or genetic counselor is the appropriate route to evaluate rare, high-penetrance mutations. ExomeDNA's profile does not screen for these variants.
• Invest in broad brain health. While no intervention is proven to prevent FTD, evidence supports cardiovascular risk reduction, regular physical activity, sustained social engagement, and adequate sleep as broadly protective for neurological aging.
• Recognize warning signs. Behavioral changes, personality shifts, or language difficulties in mid-life — especially with relevant family history — warrant clinical evaluation rather than reassurance from a genetic score.
• Contextualize the result. A common-variant signal near TMEM106B does not mean FTD is likely or predetermined. Individual absolute risk remains low for most people even at higher ends of the polygenic score distribution.

Related traits and genes

Frontotemporal dementia shares genetic pathways and biological terrain with several related neurological conditions. These links reflect shared mechanisms — lysosomal dysfunction, neuroinflammation, and protein aggregation biology:

• Alzheimer's Disease Genetic Risk — distinct genetic architecture but overlapping lysosomal and neuroinflammatory themes; TMEM106B has been implicated in Alzheimer's neuropathology as well
• ALS Genetic Risk — C9orf72 and UNC13A connect FTD and ALS on a biological spectrum; overlap is well-established in both genetics and clinical presentation
• Parkinson's Disease Genetic Risk — TMEM106B variants have appeared in Parkinson's genetic studies, linking lysosomal biology across neurodegenerative conditions
• Cognitive Aging and Memory Decline — broader category trait on the genetics of cognitive aging
• Neuroinflammation and Brain Health — cross-category trait sharing MHC region immune signals including HLA-DRA and HLA-DRB5

Frequently asked questions

Is frontotemporal dementia hereditary? FTD has a meaningful hereditary component. Strong familial forms — caused by rare high-penetrance mutations in C9orf72, GRN, and MAPT — run clearly in some families. Common genetic variants identified in genome-wide studies contribute modestly at the population level but are separate from these familial mutations. ExomeDNA's FTD profile captures the common-variant layer; it does not screen for familial high-penetrance mutations, which require separate clinical genetic testing.

What does TMEM106B have to do with frontotemporal dementia? TMEM106B encodes a lysosomal protein involved in regulating lysosomal function and cellular protein clearance. Research has associated common variants near this gene with FTD risk across multiple independent studies, particularly in cases involving TDP-43 protein accumulation — the most common FTD pathological subtype. TMEM106B is among the most consistently replicated loci in FTD genetics, and variants near this gene have also been implicated in Parkinson's disease and other neurodegenerative conditions, suggesting a shared role in neuronal protein handling biology.

Can a genetic test tell me if I'll develop frontotemporal dementia? No. Common-variant polygenic scoring for FTD provides population-level risk context; it is not able to tell you whether you or any specific person will develop the condition. Absolute lifetime risk for FTD is substantially lower than for many common diseases. For anyone with a strong family history, clinical genetic counseling with targeted testing for high-penetrance mutations is the informative path.

What is the difference between familial FTD mutations and common GWAS variants? Rare familial mutations — C9orf72 repeat expansions, GRN loss-of-function variants, and certain MAPT changes — appear at low population frequencies but substantially increase risk and often cause FTD in affected families. Common GWAS variants appear at much higher frequencies and each contributes a small statistical effect. ExomeDNA captures the common-variant layer; clinical genetic testing evaluates the rare familial layer. The two do different things and answer different questions.

What should I do if several family members have had early-onset dementia or FTD? Speak with your primary care physician about a referral to a genetic counselor or neurogenetics clinic. Specialists can review your family history, recommend appropriate testing for rare high-penetrance mutations, and help you understand results in clinical context. Common-variant DTC scoring is not a substitute for this evaluation when significant family history is present.

This page is for educational purposes only. ExomeDNA does not provide clinical guidance. For health-related questions or concerns, please consult a qualified healthcare provider.

[FDA Wellness Compliance Footer — content from legal/fda-wellness-footer.md]

References

1. Ferrari R, Hemingway A, Sherrington R, et al. (2014). Frontotemporal dementia and its subtypes: a genome-wide association study. Lancet Neurology. PMID: 24931836.
2. [Author et al.] (2014). Frontotemporal dementia genetic study. PMID: 24943344.
3. [Author et al.] (2015). Frontotemporal dementia genetic study. PMID: 26154020.
4. [Author et al.] (2018). Frontotemporal dementia genetic study. PMID: 29724592.
5. [Author et al.] (2021). Frontotemporal dementia genetic study. PMID: 34475377.

Data sources:

• GWAS Catalog (NHGRI-EBI, accessed 2026-05-29)
• Open Targets Platform (CC0 1.0, accessed 2026-05-29)
• ClinVar (NCBI, accessed 2026-05-29) — entries at ≥2-star review status
• ClinGen Gene-Disease Validity (CC0 1.0, accessed 2026-05-29)