Nikolaus Friedreich and degenerative atrophy of the dorsal columns of the spinal cord.

Nikolaus Friedreich (1825-1882) presented clinical findings in six patients with a severe hereditary disorder of the nervous system and secured full autopsies in four of them. He was fascinated by the spinal cord lesions in the siblings of two unrelated families, and in the first three of his five long articles stressed the destruction of the dorsal columns. He recognized the relatively minor symmetrical lesions of the anterolateral fasciculi but did not separate dorsal spinocerebellar tracts (Flechsig's bundles) and corticospinal tracts. Although he studied the dorsal spinal roots in great detail and established their principal abnormality, namely, axonal thinning without axonal loss, he reported dorsal root ganglia as entirely normal. He made an insightful description of atrophic neurons in the gracile nuclei (clavae) but overlooked the invariable atrophy of the dentate nuclei. He followed the families over a period of 14 years, but acknowledged the hereditary nature of the disease only very late. He proposed a developmental defect for the medulla oblongata, retaining his interpretation that the spinal lesion was inflammatory. This review honors Friedreich for his insight into a 'new' disease in the late 19th century and updates his neuropathological findings. It is remarkable that Friedreich also described the abnormal hearts in the disease that now bears his name since hypertrophic cardiomyopathy is now recognized as the main cause of death in Friedreich's ataxia.

Therapeutic strategies in Friedreich's ataxia.

First established as a diagnosis by Nikolaus Friedreich in 1863, Friedreich's ataxia (FA) is an autosomal recessive progressive neurodegenerative disorder cause by a trinucleotide repeat expansion. FA begins with the functional absence of the FXN gene product frataxin, a protein whose exact function still remains unknown. This absence results in impaired intracellular antioxidant defenses, dysregulation of iron-sulfur cluster proteins, depression of aerobic electron transport chain respiration, massive mitochondrial dysfunction, and ultimately cell death in the brain, spinal cord and heart. Herein, we review the molecular and cellular pathogenesis leading to widespread organ system dysfunction, as well as current therapeutic research aimed at preventing the debilitating effects of frataxin loss and preventing the signs and symptoms associated of FA. We also discuss the ongoing treatment strategies employed by our laboratory to prevent mitochondrial damage using synergistic effects of 17ß-estradiol and methylene blue, previously shown by our group and others to have protective effects in human FA fibroblasts. This article is part of a Special Issue entitled Hormone Therapy.

Friedreich's ataxia: pathology, pathogenesis, and molecular genetics.

The pathogenic mutation in Friedreich's ataxia (FRDA) is a homozygous guanine-adenine-adenine (GAA) trinucleotide repeat expansion on chromosome 9q13 that causes a transcriptional defect of the frataxin gene. Deficiency of frataxin, a small mitochondrial protein, is responsible for all clinical and morphological manifestations of FRDA. This autosomal recessive disease affects central and peripheral nervous systems, heart, skeleton, and endocrine pancreas. Long expansions lead to early onset, severe clinical illness, and death in young adult life. Patients with short expansions have a later onset and a more benign course. Some are not diagnosed during life. The neurological phenotype reflects lesions in dorsal root ganglia (DRG), sensory peripheral nerves, corticospinal tracts, and dentate nuclei (DN). Most patients succumb to cardiomyopathy, and many become diabetic during the course of their disease. This review seeks to reconcile the diverse clinical features with pathological and molecular data. In the pathogenesis of the lesion in DRG, dorsal spinal roots, and sensory peripheral nerves, developmental defects and atrophy occur in combination. The progressive lesion of the DN lacks a known developmental component. Destruction of the DN, optic atrophy, and degeneration of the corticospinal tracts are intrinsic central nervous system lesions. Fiber loss in dorsal columns and spinocerebellar tracts, and atrophy of the neurons in the dorsal nuclei of Clarke are secondary to the lesion in DRG. The role of frataxin deficiency in the pathogenesis of FRDA is still unclear because the protein has multiple functions in the normal state, including biogenesis of iron-sulfur clusters; iron chaperoning; iron storage; and control of iron-mediated oxidative tissue damage.

Friedreich's ataxia--yesterday, today and tomorrow.

The present review traces the origin of Friedreich's Ataxia (FA) from the time of Nikolaus Friedreich in the mid-nineteenth century. The early hesitation on the part of the neurological community in accepting FA as a distinct entity, rather than a variant form of tabes dorsalis and multiple sclerosis, has been highlighted. Research within the last 6-7 years, has firmly established FA as a trinucleotide repeat disorder, the location of the offending gene, and the disease-related gene product, frataxin. Frataxin is now thought to interfere with the mitochondrial oxidative process and enhance iron accumulation. However, whether this iron accumulation is a primary causative event for symptom production is not clear and iron chelators are unlikely to be helpful in therapy. Of great promise is the use of free radical scavengers and antioxidants. One such agent idebenone, a short chain analogue of co-enzyme Q10, may have a future.

Origin of Friedreich's disease in Quebec.

We have been able to trace 40 cases of classical Friedreich's disease from 14 previously unrelated French Canadian kindreds to one common ancestral couple arriving in New France in 1634: Jean Guyon and Mathurine Robin. One member of this couple presumably introduced one gene for Friedreich's disease into the French Canadian population. This gene has now been traced over 12 generations to both parents of the present cases. We plan to use this knowledge to study the spectrum of clinical manifestations of this gene and to carry out gene chromosomal localization studies, using the techniques of linkage and of molecular biology. Such studies in rare autosomal recessive disorders have previously been judged to be almost impossible.

[Roussy-Levy hereditary areflexic dysstasia. Its historical relation to Friedreich's disease, Charcot-Marie-Tooth atrophy and Dejerine-Sottas hypertrophic neuritis; the present status of the original family; the nosologic role of this entity]. / La dystasie aréflexique héréditaire de Roussy-Lévy. Ses rapports historiques avec la maladie de Friedreich, l'atrophie Charcot-Marie-Tooth et la névrite hypertrophique de Dejerine-Sottas; l'état actuel de la famille originale; la place nosologique de cette entité.

This survey of Roussy-Lévy disease begins with an historical account of the three neurological conditions from which this entity has been separated: Friedreich disease, described in 1861-1863, which proved with time to be a genuine anatomoclinical disorder: Charcot-Marie-Tooth atrophy, described in 1886, particular because of its morphology and evolution but due to various processes: Dejerine-Sottas hypertrophic neuritis, described in 1893, which was the first variant to be individualized within the heterogenous group of primary and familial hypertrophic neuritis. The initial description of Roussy-Lévy disease--in 1926, 1932, and 1934--and the controversies raised by this concept are recalled as well as the present state of the original family: five out of seven members have been examined since 1956 and it has been demonstrated that they are suffering from a form of hypertrophic neuritis. However it is this author's opinion that the concept of an autonomous Roussy-Lévy disease within hypertrophic neuritis is justified by the following criteria: dominant transmission, very precocious onset, extreme slowness of the evolution, remarkable benignity of the prognosis.

Nicolaus Friedreich and degenerative atrophy of the posterior columns of the spinal cord.

A short outline is given of the pioneer efforts of Nicolaus Friedreich in the description of the spinocerebellar degeneration which now bears his name.