An association study between SNAP-25 gene and attention-deficit hyperactivity disorder.

Attention-Deficit Hyperactivity Disorder (ADHD) is the most common behavioral disorder in childhood. Genetic associations have been reported between ADHD and polymorphic variants within or near dopamine pathway genes. Synaptosomal-associated protein, 25 kDa (SNAP-25), a presynaptic plasma membrane protein with an integral role in synaptic transmission, has shown association with ADHD in several datasets. We characterized two single-nucleotide polymorphisms (rs362549, rs363006) and one microsatellite [5'-UTR (TAAA)(n)] of SNAP-25. The association of these variants with ADHD was assessed in 102 trios collected from 90 male and 12 female probands. Transmission disequilibrium test (TDT) analysis showed that none of the polymorphic alleles were preferentially transmitted to the probands. Quantitative analysis was also conducted to assess the relationship between these marker alleles and the severity of ADHD symptoms. Analysis of the DSM-IV subtypes indicated that a significant association was identified between SNP rs362549 and ADHD subtypes (P = 0.0047). This is the first report of an association between SNAP-25 and ADHD in Chinese subjects of Han descent. We still support the premise that SNAP-25 is a genetic susceptibility factor for ADHD.