Ataxic neuropathy

Osuntokun BO. 1968. An ataxic neuropathy in Nigeria A clinical, biochemical and electrophysiological study. Brain 91 215-248. 

Abetalipoproteinemia (ABL) is a rare, autosomal recessive disease first described by Bassen and Kornsweig in 1950. It is characterized by the absence of plasma apoB lipoproteins, fat-soluble vitamin deficiencies (A, E, and K), and the presence of acanthocytosis (Table 27-1). Other signs include fat malabsorption presenting as steatorrhea, flatus, abdominal discomfort, and progressive ataxic neuropathy. The key diagnostic feature is an extremely low plasma total cholesterol and absence of all apoB lipoproteins (chylomicrons, VLDL, and LDL). 

Several investigations have suggested that consumption of residual cyanide in cassava products causes paralytic disorders, such as konzo (Spencer, 1994 Tylleskar, 1994) and tropical ataxic neuropathy (Osuntokun, 1994 Spencer, 1994). In both conditions, the pathogenic mechanism is still unknown. In addition, there are indications that the long-term effects of increased cyanide consumption might include diabetes (Akanji, 1994). 

Peripheral neuropathies, autoimmune. Acute or chronic inflammatory neuropathies leading to demyelination and axonal damage of nerves and nerve roots associated with high-titred autoantibodies against gangliosides (e.g. Guillain-Barre syndrome, Miller-Fisher syndrome, acute sensory ataxic neuropathy). 

Despite the apparent effectiveness of traditional methods of preparing cassava dishes in reducing the cyanide content, there is evidence to indicate that a tropical disease known as ataxic neuropathy may be associated with the consumption of cassava (31, 32, 33). One of the metabolic routes whereby cyanide is detoxified involves the formation of thiocyanate as shown in Figure 7. Elevated levels of thiocyanate in blood plasma have been observed in individuals who suffered from ataxia neuropathy and who had a history of high consumption of cassava. Rats fed boiled or fermented cassava also showed high levels of thiocyanate in plasma and developed clinical signs of ataxia neuropathy. The mechanism whereby cyanide or its metabolic product, thiocyanate, are involved in the pathogenesis of this disease remains to be elucidated. 

Cyanide poisoning has been reported8 from eating chokecherries, bitter almonds, and apricot pits. In addition, cyanide is found in lima beans and cassava beans and roots. Cassava is a staple in certain countries and is blamed for the high incidence of tropical ataxic neuropathy in those areas. 

Heterozygotes, in general, are asymptomatic and do not exhibit acanthocytosis. Exceptions may be the case of a maternal uncle of the patient of Mier et al. (1960), who at the age of 19 developed ataxic neuropathy and deterioration of vision, and who expired at the age of 27 years. A paternal cousin of the same patient had instability of gait and impairment of vision at the age of 6 years (cit. after Schwartz et al. 1963). Salt et al. (1960) examined all four grandparents, the parents and two maternal uncles of their patient. Serum lipids were abnormal in both parents and in the paternal grandfather, the level of /8-lipoproteins being one half of normal. Total lipids, cholesterol and phospholipids were decreased accordingly. Chylomicrons were observed in both parents after a fatty meal. 

Mier, M., S. 0. Schwartz, and B. Boshes Acanthocytosis, pigmentary degeneration of the retina and ataxic neuropathy a genetically determined syndrome with associated metabolic disorder. Blood 16, 1586 (1960). 

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