Controlled study of erythrocyte choline in Tourette syndrome.

Erythrocyte and plasma choline parameters were compared in children (n = 63), aged 6-18 years, suffering from Tourette Syndrome (TS), their parents (n = 57), their unaffected siblings (n = 38), and an adult control group (n = 57). Factors such as severity of illness, medication status, and gender had no effect on erythrocyte choline. TS patients showed elevations in erythrocyte choline level compared to controls. Furthermore, the erythrocyte choline concentration in TS patients with a history of TS or chronic motor tic disorder (CMT) in first-degree relatives showed a positive correlation with that of their parents (r2 = 0.6, p less than 0.03). Erythrocyte choline values in TS patients without such positive family history do not demonstrate a familial relationship. Positive history of TS or CMT in first-degree relatives accounts for the observation of elevated erythrocyte choline in unaffected siblings of TS patients. Age effects on erythrocyte choline were found in the TS patients only (r = -0.14, p less than 0.04) and not in parents, siblings, or normal controls. A gender effect on plasma choline was noted with male levels 23% higher than in females. The present findings support the utility of erythrocyte choline as a marker for the familial expression of the TS diathesis.