Significant association of the arylalkylamine N-acetyltransferase ( AA-NAT) gene with delayed sleep phase syndrome.

Arylalkylamine N-acetyltransferase (AA-NAT) is a rate-limiting enzyme in melatonin hormone synthesis and participates in daily oscillations of the melatonin level. We studied the association between the AA-NAT gene and delayed sleep phase syndrome (DSPS). Results indicate that there is a significant difference in allele positivity at the single nucleotide polymorphism involved in an amino acid substitution from alanine to threonine at position 129 between patients with DSPS and healthy controls.