Endothelin receptor A -231 G>A polymorphism: No linkage to primary pediatric headache

Objective. - To assess whether the biallelic -231 G>A polymorphism of the endothelin type A receptor (EDNRA) gene, previously shown to be a marker of increased risk for developing migraine, has a role in the susceptibility to primary pediatric headache. Background. - Several studies suggest that endothelin has a role in migraine. A recent association study has shown that the biallelic -231 G>A polymorphism of the EDNRA gene is associated to migraine in an elderly population. Methods. - A total of 126 consecutive unrelated pediatric patients affected by primary headache, classified according to the International Headache Society criteria in migraine (migraine with aura, n = 3; migraine without aura, n = 80), and tension-type headache (episodic tension-type headache, n = 36; chronic tension-type headache, n = 7) patients, were recruited to the study. Sixty-seven healthy blood donors were used as a control group. Genomic DNA was extracted from buccal swabs or blood samples and analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for the above-mentioned polymorphism. Allele and genotype frequencies for primary headache patients were analyzed in comparison with the control group. Results. - No significant differences were found in the distribution of the EDNRA -231 G>A polymorphic variant when considering both genotype (migraine χ²= 2.78, P= .25; tension-type headache χ²= 3.58, P= .17) and allelic frequencies (migraine χ²= 1.48, P= .22; tension-type headache χ²= 0.39, P= .56). Furthermore, no significant genotype-related difference was found in relation to clinical features, such as age at onset, frequency, and length of the attacks. Conclusions. - Our study shows that the -231 G>A polymorphism in the EDNRA gene is neither associated with primary juvenile headache nor significantly correlated with main clinical features characteristic of the headache pathology in pediatric settings.