We present a case series highlighting the high rate of functional neurologic disorder (FND) in a sample of patients with Fahr's disease at our center.

Fahr's disease is a rare (<1 in 1,000,000 population) autosomal dominant genetic disorder, characterized by extensive calcifications in the basal ganglia, cerebellar nuclei, and cortex.  While neuropsychiatric symptoms are commonly reported, little is known about the rate of FND in people with Fahr’s disease.

We conducted a retrospective case series of all patients diagnosed with Fahr's disease at the University of Cincinnati Movement Disorders Clinic from March 2021 to July 2024. Fahr's disease was confirmed based on clinical criteria and characteristic neuroimaging with or without genetic confirmation. FND was diagnosed in accordance with published clinical criteria.

There were 6 patients with Fahr’s disease (age 24-61 years old, 4 women and 2 men). Five had genetic testing results (2 with SLC20A2 variants, 1 with a PDGFB variant, 2 negative). All 6 patients met the criteria for FND with mixed symptoms. Four (67%) had functional movement disorders, including functional tremor (n=2), functional spasms (n=2), and functional gait disorder (n=3). Four had functional spells (2 diagnosed in an epilepsy monitoring unit). Other FND symptoms included persistent perceptual dizziness (n=2), post-concussive syndrome (n=1), functional speech disorder (n=2), and variable cognitive complaints (n=5). All 6 patients had migraine headaches. Four had failed prior migraine treatments and were started on anti-CGRP medications with excellent responses. Two had significant improvement in FND symptoms in response to self-guided cognitive behavioral therapy.

There is a high prevalence of FND in our sample of Fahr's disease. Recognition of FND within other neurologic syndromes is important to treat the most important source of disability effectively.