Confirmed association between monoamine oxidase A molecular polymorphisms and Sudden Infant Death Syndrome.

We published in the February 2009 issue of Neurogenetics the article “Association of dopamine transporter and monoamine oxidase molecular polymorphisms with Sudden Infant Death Syndrome and stillbirth: new insights into the serotonin hypothesis” . The aim of our work was to investigate the contribution of additional neurotransmitters and related genes, different from the serotonin transporter (SLC6A4, 5-HTT) in the development of SIDS and stillbirth. The main conclusion discussed in the paper was that the frequency of MAOA allele 4R (having increased transcriptional activity) was statistically higher in SIDS and stillbirth than in the Control Group. The conclusions in our article have recently been submitted to criticism by Klintschar and Heimbold with a Letter to the Editor of Neurogenetics. We would kindly reply to their two main observations.