A functional polymorphism in the tyrosine hydroxylase gene indicates a role of noradrenalinergic signaling in sudden infant death syndrome.
OBJECTIVE
Catecholamines may contribute to the cause of sudden infant death syndrome (SIDS). TH01, a tetrameric short tandem repeat marker in the tyrosine hydroxylase gene, regulates gene expression and catecholamine production.


METHODS
We investigated TH01 in 172 German Caucasian SIDS cases and 390 sex- and age-matched control subjects.


RESULTS
The *9.3 alleles were more frequent in patients with SIDS than in control subjects (40.12% vs 31.15%; P = .006). For homozygotes the odds ratio was 1.83 (95% confidence interval: 1.09-3.05), for carriers 1.58 (1.09-2.28). Moreover, *9.3 alleles were significantly more frequent during the winter (47.73% vs 35.38% in the warmer seasons), and the frequency of *9.3 alleles varied significantly with the age at death (weeks 7 to 12: 49.04% vs 29.63% within the first 6 weeks). Other risk factors (sleeping position, gestation, smoking) had no significant impact on the frequency of *9.3.


CONCLUSIONS
Our results indicate a relationship between SIDS and TH01 genotype, presumably caused by an impairment of breathing regulation or arousal. We propose that noradrenalinergic neuronal activity contributes to the cause of a major subset of SIDS victims. Moreover, the results further stress that SIDS is a highly heterogenic group.
Klintschar
Michael
M
Institute of Legal Medicine, Georg August University Göttingen, Göttingen, Germany. michael.klintschar@med.uni-goettingen.de
Reichenpfader
Barbara
B
Saternus
Klaus-Steffen
KS
D001344:Autopsy; D016022:Case-Control Studies; D002395:Catecholamines / Q000378:metabolism; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D006801:Humans; D007223:Infant; D008297:Male; D011110:Polymorphism, Genetic; D015398:Signal Transduction; D013398:Sudden Infant Death / Q000235:genetics*; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics* / Q000378:metabolism
D002395:Catecholamines; D005819:Genetic Markers; D014446:Tyrosine 3-Monooxygenase