Title:Behavioural Variant Frontotemporal Dementia due to CCNF Gene Mutation:
A Case Report
Volume: 20
Issue: 5
Author(s): Feng-Ling You, Gao-Fu Xia and Jing Cai*
Affiliation:
- The First Affiliated Hospital of
Guizhou University of Traditional Chinese Medicine, Guiyang, 550001, China
Keywords:
Behavioural variant, frontotemporal dementia, amyotrophic lateral sclerosis, CCNF gene, case report, FTD.
Abstract:
Background: Frontal, temporal lobe dementia (FTD) and amyotrophic lateral sclerosis
(ALS) are fatal neurodegenerative diseases. Studies have found that CCNF mutations have been
found in patients with familial and sporadic ALS and FTD. Behavioural variant frontotemporal dementia
(bvFTD) is a clinical syndrome characterized by progressive deterioration of personality, social
behaviour, and cognitive function, which is most closely related to genetic factors. As the early
symptoms of bvFTD are highly heterogeneous, the condition is often misdiagnosed as Alzheimer's
disease or psychiatric disorders. In this study, a bvFTD patient had a CCNF gene mutation, which
led to ubiquitinated protein accumulation and ultimately caused neurodegenerative disease. Genetic
detection should be improved urgently for bvFTD patients and family members to provide a clinical
reference for early diagnosis of frontotemporal dementia.
Case Presentation: In this case, the patient was 65 years old with an insidious onset, early-onset
memory loss, a significant decline in the episodic memory, an early AD diagnosis, and oral treatment
with donepezil hydrochloride for 3 years with poor efficacy, followed by a change to oral memantine
hydrochloride tablets, which controlled the condition for several months. His medication
was switched to sodium oligomannate capsules, and his condition was gradually controlled, but no
significant improvement was observed. After spontaneous drug withdrawal, the patient’s condition
progressed rapidly; therefore, he visited our hospital and underwent neuropsychological tests for
moderate to severe cognitive impairment. AD cerebrospinal fluid markers showed no significant abnormalities,
and cranial MRI revealed frontotemporal lobe atrophy and decreased hippocampal volume.
Genetic testing for the presence of the CCNF gene revealed a c.1532C > A (p. T511N)
heterozygous variant, which might be a diagnostic criterion for bvFTD. Therefore, the patient's
symptoms recurred after transient improvement with the combination of donepezil, oral memantine
hydrochloride tablets, and sodium oligomannate, but his overall condition was improved compared
to that before, and this treatment regimen was continued to observe changes during the follow-up.
Conclusion: The early clinical manifestations of bvFTD are complex and variable, and the condition
is easily misdiagnosed, thus delaying treatment. Therefore, for patients with a high clinical suspicion
of FTD, in addition to a detailed understanding of their medical history and family history
and improvement of relevant examinations, genetic testing should be performed as early as possible
to help confirm the diagnosis. For diseases closely related to genes, genetic testing of other family
members should be optimised as much as possible to allow early diagnosis and intervention and
guide fertility in the next generation.
