Sudden infant death syndrome (SIDS) constitutes a considerable percentage of infant death of unknown etiology. Individual catecholamine response variation is suspected to play a role in SIDS. TH01 is a tetrameric short tandem repeat marker in the tyrosine hydroxylase gene, which regulates gene expression and catecholamine production with allele 9.3 exerting a particularly strong effect on noradrenalin production. The current study found that genotypes containing one or two 9.3 alleles were significantly more frequent in SIDS patients (58.2 percent) than in control subjects (48.4 percent, p = 0.038), whereas all other alleles were more frequent in the control subjects. The study findings support the notion that there exists a significant association between TH01 gene configuration and SIDS. (Published Abstract)