TREM2 variants as a possible cause of frontotemporal dementia with distinct neuroimaging features.

BACKGROUND AND PURPOSE: Nasu-Hakola disease (NHD) is a rare, autosomal recessive disorder characterized by skeletal and neurological symptoms. Behavioral symptoms with cognitive impairment may mimic the behavioral variant of frontotemporal dementia (bvFTD) and other early-onset dementias. Our patients were analyzed and the literature was reviewed to delineate neurological and neuroimaging findings suggestive of NHD. METHOD: Fourteen patients carrying a pathogenic mutation in the TREM2 gene were found in our database. Demographic, clinical, laboratory and radiological data were retrieved and analyzed. RESULTS: The presenting clinical picture was behavioral changes with cognitive decline resembling bvFTD in all patients. The mean age was 37.1 ± 4.97 years and the mean duration of the disease was 8.9 ± 3.51 years. Only two patients had typical bone cysts. Seven patients had bilateral calcification of the basal ganglia in computed tomography of the brain. Magnetic resonance imaging of the brain revealed severe atrophy of the corpus callosum, enlargement of the ventricles, atrophy of the caudate nuclei and periventricular white matter changes in all patients. Symmetrical global atrophy of the brain mainly affecting frontoparietal and lateral temporal regions were observed in all cases, and 13 patients had atrophy of the hippocampus. Cerebrospinal fluid examination of 10 patients showed elevated protein levels in six and the presence of oligoclonal bands in four patients. CONCLUSION: A combination of white matter changes, enlarged ventricles, atrophy of the caudate nuclei and thinning of the corpus callosum in magnetic resonance imaging strongly suggests NHD in patients with FTD syndrome. Molecular genetic analysis should be performed in suspected cases, and families should receive genetic counseling.

Impact of Confinement on the Burden of Caregivers of Patients with the Behavioral Variant of Frontotemporal Dementia and Alzheimer Disease during the COVID-19 Crisis in France.

INTRODUCTION: The clinical presentation of the behavioral variant of frontotemporal dementia (bvFTD) differs from that of Alzheimer disease (AD), with major impairments in behavioral functions in bvFTD and cognitive impairment in AD. Both behavioral disturbances in bvFTD and cognitive impairment in AD contribute to caregiver burden. OBJECTIVE: To investigate the impact of home confinement during the COVID-19 crisis on the burden of caregivers of bvFTD or AD patients. METHODS: During the COVID-19 lockdown in France, neurologists and neuropsychologists from the Memory Center of Nantes Hospital conducted teleconsultations for 38 AD patients and 38 bvFTD patients as well as for their caregivers. During these consultations, caregivers were invited to rate the change in their burden during home confinement. They were also invited to rate behavioral or emotional changes in the patients during, compared with before, the confinement. RESULTS: Twenty-two bvFTD caregivers and 14 AD caregivers experienced an increase in burden. For bvFTD caregivers, this increased burden occurred regardless of behavioral changes, while AD caregivers experienced an increased burden related to changes in patients' neuropsychiatric symptoms. Among the whole cohort, 2 factors were associated with increased caregiver burden: behavioral change and bvFTD. CONCLUSION: The results demonstrate that during home confinement in the COVID-19 crisis, neuropsychiatric symptoms were the core factor that impacted caregiver burden in different ways depending on the disease.