The study ai
ms were twofold: 1) identify the localization and the cytoarchitecture of the retrotrapezoid nucleus (RTN) in the hu
man fetus and infant and 2) ascertain if the RTN, given its essential role in ani
mal studies for the
maintenance of breathing and che
moreception, showed abnor
malities in victi
ms of sudden perinatal and infant death (sudden intrauterine unexplained death/SIUD ¡ª and sudden infant death syndro
me/SIDS). We exa
mined SIDS and SIUD cases and Controls (n = 58) fro
m 34 gestational weeks to 8
months of postnatal age by co
mplete autopsy, in-depth autono
mic nervous syste
m histological exa
mination, and i
mmunohistoche
mical analysis of the
m>PHOX2Bm> gene, a transcriptional factor involved in Congenital Central Hypoventilation Syndro
me that has been defined as a
marker of rat RTN neurons.
We identified a group of PHOX2B-immunopositive neurons within the caudal pons, contiguous to the facial/parafacial complex, in 90 % of Controls, likely the homologous human RTN (hRTN). We observed structural and/or m>PHOX2Bm>-expression abnormalities of the hRTN in 71 % of SIUD/SIDS cases m>vsm> 10 % of Controls (p < 0.05).
In conclusion we suggest that developmental abnormalities of the hRTN may seriously compromise chemoreception control, playing a critical role in the pathogenesis of both SIUD and SIDS.