Clinical Profile and Plasma Vitamin B6 Levels in Children with Tourette Syndrome: A Case-control Study

Tourette syndrome (TS) is a childhood-onset neuropsychiatric disorder characterized by recurrent motor and vocal tics. Histaminergic dysregulation in the brain has been proposed as a mechanism underlying TS. Vitamin B6, a key cofactor in histamine metabolism, may therefore play a contributory role in its pathophysiology.

This was an observational, unmatched case-control study in which clinical features of 25 children diagnosed with TS were assessed using the Yale Global Tic Severity Scale. Plasma vitamin B6 levels were measured using enzyme-linked immunosorbent assay (ELISA) and compared with those of a control group.

Most participants were males, and 16% had comorbid attention deficit hyperactivity disorder (ADHD) or obsessive-compulsive disorder (OCD). The most common motor tics were eye blinking, shoulder shrugging, head jerking, and orofacial movements. Frequent vocal tics included throat clearing and sniffing. Coprolalia was observed in four children. The median plasma vitamin B6 level in the TS group was 25.01 ng/mL, which was significantly lower than the 36.33 ng/mL in the control group (Mann-Whitney U = 225, p = .03). The rank-biserial correlation indicated a moderate effect size (r = 0.35).

TS in children predominantly affects males and is commonly associated with ADHD and OCD. Coprolalia-a clinically distressing symptom-was present only in a small subgroup. The lower plasma vitamin B6 levels observed in children with TS suggest a possible role for vitamin B6 in disease pathogenesis, potentially through its involvement in histaminergic and GABAergic neurotransmission and in modulating neuroinflammatory processes.