No Correlation between AVPR 1A Promoter Polymorphisms and Prepulse Inhibition in Patients with Nocturnal Enuresis

Introduction: A correlation between AVPR1A promoter polymorphisms and prepulse inhibition (PPI) of startle reflexes has been described in healthy adults. Many children with nocturnal enuresis (NE) have a reduced PPI and treatment with desamino arginine vasopressin (dDAVP), a ligand of the arginine vasopressin receptor 1A (AVPR1A), and both improve clanical symptoms and significantly increase PPI. Methods: In 17 children (median 9.1 years, range 6.4-17.3) with NE, promoter repeats within the RS1 and RS3 regions of AVPR1A were quantified and correlated to PPI (native and age-adjusted). Results: No direct correlation was found between the number of promoter repeats at RS1 and PPI (correlation coefficient—0.240, p = 0.346) or RS3 and PPI (correlation coefficient—0.0192, p = 0.936), with no change through age-adjustment of PPI. The different RS3 length subgroups did not show differences in PPI, nor did differentiation of NE according to clinical subtype or treatment response to dDAVP show differences in the number of promoter repeats. Conclusion: The missing reproducibility of the correlation between AVPR1A promoter polymorphisms and PPI in a group with wide range of PPI suggests a more complex interaction. Therefore, further investigations are needed to analyze this very plausible interaction. Conditions with a reduced PPI, such as enuresis, schizophrenia or autism, are particularly interesting for this research.