Abnormal behaviour of the erythrocyte membrane sodium-lithium counter-transporter (SLC) is associated with plasma triglyceride concentrations. Refsum's disease is characterized by progressive neurological dysfunction and accumulation of phytanic acid, an isoprenoid fatty acid, in fat-containing tissues.Methods
This study explored the effects of plasma phytanic acid on SLC kinetics in nine Caucasian patients with Refsum's disease and in age- and sex-matched Caucasian control subjects.Results
A dose-dependent association was seen between countertransporter maximal velocity and phytanic acid content of low-density lipoprotein (LDL)-cholesterol (r = −0.61, r = −0.65 respectively; P = 0.05, P = 0.04) and high-density lipoprotein (HDL)-cholesterol (r = −0.81, −0.82 respectively; P = 0.005, P = 0.003). No significant association was seen with the sodium affinity of the transporter (r = −0.44, P = 0.20, for LDL; and −0.43, P = 0.21, for high-density lipoprotein).Conclusion
These findings suggest that phytanic acid may alter the behaviour of the sodium-lithium countertransporter.