If several biological relatives have frontotemporal dementia (FTD), prepare a detailed family health history and discuss it with the clinician evaluating your risk. Several affected relatives raise concern about familial FTD, but the pattern alone does not prove an inherited cause. FTD can resemble a mood disorder or overlap with other dementias. Clinicians assess the full history alongside examinations, testing, and imaging, according to the National Institute on Aging.
Medical information disclaimer: This article is for general educational purposes only and does not provide medical advice, diagnosis, or treatment. Always consult a physician or other qualified health professional about symptoms, medications, tests, or treatment decisions.
Table of Contents
- Which relatives should you include?
- What information should you record?
- Look beyond the label "FTD"
- What does the family pattern mean?
- How should genetic testing be approached?
Which relatives should you include?
Start with relatives who are biologically related to you. Cover both sides of the family rather than focusing only on the branch with a known FTD diagnosis.
Include: The CDC recommends recording this information, updating it over time, and sharing it with relatives and the clinician assessing risk. Spouses can help supply information, but their illnesses do not indicate your inherited risk.
- Parents, siblings, and half-siblings
- Children
- Grandparents
- Aunts and uncles
- Nieces and nephews
What information should you record?
Create one entry for each relative, including unaffected relatives when their information is known. Their ages and place within the family help a clinician interpret the overall pattern. For each person, record: keep onset age and diagnosis age separate.
A person may have developed language or behavior changes years before receiving a formal diagnosis. Use "unknown" when necessary instead of filling gaps with assumptions. note who supplied secondhand information so a clinician can distinguish documented facts from family recollections.
- Biological relationship to you
- Specific diagnosis, if known
- First symptoms and how they changed
- Age when symptoms began
- Age at diagnosis
Look beyond the label "FTD"
Do not count only relatives whose records explicitly say FTD. Familial disease can appear differently among relatives, so related neurological or psychiatric histories may clarify the pattern.
Record diagnoses or symptoms involving: This broader view matters because genetic FTD may produce different conditions within one family, according to GeneReviews. For example, a family record of ALS is relevant because a variant in *C9orf72* can cause FTD, ALS, or both.
- Amyotrophic lateral sclerosis (ALS)
- Progressive language decline or primary progressive aphasia (PPA)
- Parkinsonism or other movement problems
- Major behavior or personality changes
- Psychiatric diagnoses
What does the family pattern mean?
Several affected relatives increase concern, especially when illnesses appear across generations or include FTD-related conditions. They still do not establish that one genetic variant caused every case. The National Institute on Aging estimates that about one-third of FTD cases are inherited, while most have no known cause.
The principal genes associated with familial FTD are *MAPT*, *GRN*, and *C9orf72*. Similar symptoms also do not guarantee identical diagnoses. Medical records can help separate confirmed FTD from suspected dementia, psychiatric illness, language disorders, or movement conditions.
How should genetic testing be approached?
Ask for a genetic counselor to review the family history before anyone chooses testing. The counselor can organize the pedigree—a family tree focused on health—and explain what different results could and could not show. When possible, genetic evaluation should begin with a living relative who has FTD. Finding a causal variant in that person makes predictive testing for unaffected relatives more informative, as the Association for Frontotemporal Degeneration explains.
If an affected person has an FTD-causing variant, each child has a 50% chance of inheriting that familial variant, and siblings may also be at risk. However, a test generally cannot predict whether symptoms will occur, when they might begin, the first syndrome, severity, or progression rate. Bring the completed history and copies of available records to the appointment. If testing cannot start with an affected relative, ask the counselor how that limitation changes the meaning of a negative or uncertain result.
