My family has confirmed C9 mutation on my dad’s side. My dad and his sister passed from ALS in 2019 and 2020. My uncle has tested positive but is around 80yrs and not shown signs of ALS. He was recently diagnosed with Alzheimer’s and my aunt insists that this isn’t related. Would it be possible that this is a misdiagnosis and he actually is developing FTD? And if so, how much difference would it make in terms of treatment?
Alzheimer’s misdiagnosed?
- Thread starter AniSk
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AnxiousStatsGuy
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How old were your father and aunt?
The average age for C9 is late 50's, though recent research has shown that the overall variability is quite high and that some families might tend to get it later or earlier. But 80 is right towards the tail of when C9 tends to show itself.
Additionally, it was thought (or assumed?) for a long time that C9 has 90%+ penetration (90% or more of people with C9 will show symptoms by.. I think the baseline is normally 80 or 85 y/o). One study came out recently estimating it could be as low as 25%, though again, with a big amount of variability between families.
I believe ~20% of people 80+ have Alzheimer's, which is obviously very common.
Given that he's actually tested positive for C9, it seems quite likely that it would indeed be C9 manifesting itself, but it is not out of the question that it could be Alzheimer's.
Do you know what his symptoms are / if he's had imaging of his brain?
Regardless, I'm sorry to hear about your uncle's dementia, whether it's true Alzheimer's or C9-FTD.
The average age for C9 is late 50's, though recent research has shown that the overall variability is quite high and that some families might tend to get it later or earlier. But 80 is right towards the tail of when C9 tends to show itself.
Additionally, it was thought (or assumed?) for a long time that C9 has 90%+ penetration (90% or more of people with C9 will show symptoms by.. I think the baseline is normally 80 or 85 y/o). One study came out recently estimating it could be as low as 25%, though again, with a big amount of variability between families.
I believe ~20% of people 80+ have Alzheimer's, which is obviously very common.
Given that he's actually tested positive for C9, it seems quite likely that it would indeed be C9 manifesting itself, but it is not out of the question that it could be Alzheimer's.
Do you know what his symptoms are / if he's had imaging of his brain?
Regardless, I'm sorry to hear about your uncle's dementia, whether it's true Alzheimer's or C9-FTD.
Nikki J
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It is possible for a misdiagnosis of course. It was common before fid was well understood and c9 unknown. C9 carriers have some brain atrophy on mri even fairly young and with absolutely normal function and neurocognitive testing. There is no treatment for ftd though. There are some meds for AD.
It is also true that some c9 people have AD on postmortem exam even when their diagnosis was FTD. Aside from the fact c9 does not make people immune to other diseases, there is thought that the protein pathologies caused by c9 may extend to tau too
It is also true that some c9 people have AD on postmortem exam even when their diagnosis was FTD. Aside from the fact c9 does not make people immune to other diseases, there is thought that the protein pathologies caused by c9 may extend to tau too
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