Dietary Effects on Serum-Phytanic-Acid Levels and on Clinical Manifestations in Heredopathia Atactica Polyneuritiformis

Localization of the oxidative defect in phytanic acid degradation in patients with refsum's disease

“…In the course of the present studies, the opportunity arose to check for possible effects of the patient's endogenous pool size. As reported previously (20), treatment with a diet low in phytol and phytanic acid causes the plasma phytanate levels in patients with HAP to fall progressively. Similar diet treatment in patients J. S. and K. S. during the present admission decreased phytanate levels to less than 50% of the initial values.2 Furthermore, analysis of adipose tissue biopsies in one patient (K. S.) showed that tissue stores were also reduced (by approximately 40%).…”

“…This is evident, first, from the fact that they apparently reach a more or less steadystate level of plasma and tissue phytanate despite continued ingestion of phytanic acid and phytol in their regular diets over many years. Their plasma and tissue levels fall when the dietary load is reduced (20 present studies with intravenously administered phytanic acid-U-m'C, in previous studies with orally administered phytol-U-14C (7,9), and in experiments with fibroblast cultures (13,14), a very low but still measurable amount of 'CO2 was produced; in all these studies, however, less than 5% of the administered substrate was converted to 14COi. Some of this "CO2 could possibly have arisen from radioimpurities that were not separated from methyl phytanate during the TLC and GLC purification.…”

Refsum's disease: characterization of the enzyme defect in cell culture

“…The proposal that on this or some other basis phytanate storage is not directly the cause of the clinical changes may also explain the discovery of patients who are clinically indistinguishable from those with HAP but who have normal phytanate levels, oxidize phytanate normally in vivo, and whose cultured fibroblasts oxidize phytanic acid at normal rates (63,8). If further clinical observations confirm the previously noted improvement on phytanic acid-low diets (49), however, a simple cause and effect relationship can be accepted.…”

“…Try (48) has compared oxidation of 3,6-dimethyloctanoate-8-14C and of randomly labeled 3,14,14-trimethylpentanoic acid in controls and in two HAP patients whose phytanate stores had been reduced by dietary means (49). The results indicated that the patients oxidized these compounds at one-third to one-half the normal rates.…”

Heredopatia atática polineuritiforme

“…6 > 10 , cujo achado no soro é atualmente considerado fundamental para o diagnóstico 7 . Dietas pobres em ácido fitânico levam a que se observe melhoria na evolução de pacientes com a doença 4 .…”