CAPOS-Syndrome: A Rare Differential Diagnosis to Friedreich’s Ataxia
26 April 2017 (online)
Background: Friedreich’s ataxia is the most common hereditary form of ataxia with an incidence of 1:50,000. Typical symptoms are ataxia, sensory neuropathy, scoliosis with further skeletal deformities, and cardiomyopathy. The disease is caused by a homozygote mutation of the frataxin gene on chromosome 9. A rare differential diagnosis in contrast to the above mentioned is the CAPOS syndrome with an incidence of 1:1,000,000. This syndrome shows likewise a progressive cerebellar ataxia, areflexia, progressive atrophy of the optic nerve, sensory-neural deafness, as well as foot abnormalities. Remarkable is the aggravation of cerebellar ataxia which can be triggered by infections. The etiology of this syndrome is not fully understood yet; few affected families show a mutation in the ATP1A3-gene.
Methods: Three patients with Friedreich’s ataxia are compared with one patient with CAPOS syndrome focusing on their clinical findings. This should help defining the CAPOS syndrome as its own clinical entity and put into focus of the clinically working neuropediatrician.
Results: The presented cases are very similar in their clinical findings, though there are some relevant differences. The infection-triggered deterioration of the ataxia is a unique feature of CAPOS syndrome.
Conclusion: The early diagnosis of the CAPOS syndrome in contrast to Friedreich’s ataxia is desirable, especially considering the absent cardiomyopathy in this syndrome. This is possible due to its clinical features. There should be a genetic tasting to harden the clinical diagnosis and further understand the etiology of the CAPOS syndrome.