Blood carnitine analysis of individuals with severe motor and intellectual disabilities in a medical welfare center

Abstract

Objective: To assess the presence of carnitine deficiency in individuals with severe motor and intellectual disability (SMID) in our center and to analyze the correlation of carnitine deficiency with sodium valproate (VPA) and nutrition. Methods: We determined blood carnitine levels in 73 patients (43 males; age, 1–58 years old; median age, 32 years old) in our center, considering blood free carnitine (FC) < 20 μmol as carnitine deficiency and FC 20–36 μmol or an acylcarnitine/FC ratio > 0.4 as risk of carnitine deficiency. The relationships of the data with VPA and nutrition were analyzed. Results: Of the 73 patients, 7 (9.6%) had carnitine deficiency, 14 (19.2%) had risk of carnitine deficiency, and 52 (4.1%) had excess carnitine. In the 66 patients not taking an L-carnitine preparation, blood FC levels were significantly lower in patients with tube feeding with carnitine-free enteral nutrition than in patients with oral feeding and those with tube feeding with addition of carnitine (both p<0.01). There was no significant difference in blood FC levels according to use of VPA. However, there was a negative correlation between VPA doses per body weight and blood FC levels (r=−0.839, p<0.01). Conclusions: Tube feeding with carnitine-free enteral nutrition was associated with high risk of carnitine deficiency and VPA was a dose-dependent risk factor for carnitine deficiency in individuals with SMID.