Fahr’s disease: what it is, causes and main symptoms
Fahr’s disease consists of the pathological accumulation of calcium in the basal ganglia and other subcortical structures. This phenomenon causes symptoms such as Parkinsonian tremors, loss of motor skills, progressive cognitive impairment and disturbances typical of psychosis, such as hallucinations.
In this article we will analyze the causes and main symptoms of Fahr’s syndrome . However, it is a very rare disease, so knowledge about it is currently limited; this may also be one of the reasons why there is no treatment for the syndrome.
What is Fahr’s syndrome?
Fahr’s syndrome is a neurodegenerative disease of genetic origin characterized by progressive bilateral calcification of the basal ganglia , a set of subcortical brain nuclei associated with learning and automation of movement, among other functions. It can also affect other regions of the brain.
Consequently, this alteration provokes motor symptoms, such as Parkinsonian tremors and dysarthria, but also psychological symptoms, including a decrease in mood and phenomena similar to those of psychosis (for example, hallucinations), and other types; it is worth noting the appearance of convulsions and ischemic strokes .
This disease was first described by the German pathologist Karl Theodor Fahr in 1930. It is also known by other names: “idiopathic calcification of the basal ganglia”, “primary familial cerebral calcification”, “cerebrovascular ferrocalcinosis”, “calcinosis of the nuclei of the brain”, “Chavany-Brunhes syndrome” and “Fritsche syndrome”.
Epidemiology and prognosis
This is a very rare disorder that affects people mostly in their 40s and 50s; calcification of the basal ganglia itself is a natural, age-related phenomenon, although it does not usually occur to the degree that is characteristic of the syndrome. Currently there is no known cure for Fahr’s disease .
It is very difficult to make predictions about the development of cases of Fahr’s disease, since research suggests that neither the severity of calcification nor the age of the patient can be used as predictors of neurological and cognitive deficits. However, the disease most commonly results in death.
Symptoms of this disease
The severity of the symptoms of Fahr’s disease varies from case to case. While many affected people do not show any signs, in other cases very severe alterations appear that alter perception, cognition, movement and other areas of functioning. Extrapyramidal symptoms are usually the first to appear.
One set of signs that has drawn special medical attention in the case of Fahr’s disease are parkinsonian symptoms, which include tremors at rest , muscle stiffness, gait disturbances, involuntary movements of the fingers or lack of characteristic facial expression, known as “mask face”.
Briefly, the most common symptoms of this syndrome are as follows:
- Progressive appearance of deficits in cognition and memory until reaching dementia
- Motor disorders such as parkinsonian tremors, athetosis, and choreic movements
- Psychotic symptoms: loss of contact with reality, hallucinations, delusions, etc.
- Alterations in sensory perception
- Loss of learned motor skills
- Eye movement and vision dysfunction
- Difficulties in walking
- Muscle stiffness and spasticity
- Phoneme articulation deficit (dysarthria) and speech slowdown
- Emotional instability and depressive symptoms
- Difficulties swallowing food and liquids
- Increased risk of ischemic stroke
Causes and pathophysiology
The signs and symptoms of Fahr’s disease are due to the accumulation of calcium and other compounds in the circulatory system , particularly in the cell walls of capillaries and large arteries and veins. Additional substances that have been detected in these deposits include mucopolysaccharides and elements such as magnesium and iron.
The key cerebral structures affected in the manifestation of Fahr’s syndrome are the basal ganglia (in particular the globus pallidus, the putamen and the caudate nucleus), the thalamus, the cerebellum and the subcortical white matter, i.e. the sets of myelinated neuronal axons below the cerebral cortex.
The pathological calcification of these regions has been mainly associated with genetic mutations transmitted by autosomal recessive inheritance . It is known that some of the affected genes are related to the metabolism of phosphate and to the maintenance of the blood-brain barrier, which is fundamental in the biochemical protection of the brain.
However, autosomal dominant inheritance only accounts for about 60% of Fahr’s disease cases. In the remainder, causes include recessive inheritance, infections such as HIV (the AIDS virus), parathyroid gland dysfunction, central nervous system vasculitis, and radiation and chemotherapy.
- Mufaddel, A. A. & Al-Hassani, G. A. (2014). Familial idiopathic basal ganglia calcification (Fahr’s disease). Neurosciences (Riyadh). 19: 171-77.
- Rastogi, R., Singh, A. K., Rastogi, U. C., Mohan, C. & Rastogi, V. (2011). Fahr’s syndrome: a rare clinico-radiologic entity. Medical Journal Armed Forces India, 67: 159-61.
- Saleem, S., Aslam, H. M., Anwar, M., Anwar, S., Saleem, M., Saleem, A. & Rehmani, M. A. K. (2013). Fahr’s syndrome: literature review of current evidence. Orphanet Journal of Rare Diseases, 8: 156.