Self-mutilation in the Lesch-Nyhan syndrome: a corporal consciousness problem?--a new hypothesis.

The Lesch-Nyhan syndrome (LNS) has been extensively studied from the genetic and biochemical point of view. The main characteristic of the syndrome is the self-mutilation feature, which has been poorly studied and understood. We propose a new hypothesis about the self-mutilation physiopathology, which is related to the supersensitivity of the dopaminergic D1 receptors in the neuromatrix found in the cingulum cortex region. The LNS shows an increase of uric acid levels as a result of the deficiency of hypoxanthine phosphoribosyltransferase enzyme. This increase could induce damage to dopaminergic neurons. As a consequence, a decrease in dopamine synthesis during gestation and the early postnatal period could occur, producing a functional dopaminergic denervation of the D1 receptors, located on the prefrontal cortex, specifically in the cingulum bundle projections. This phenomenon could induce a codification disturbance in the 'genetic body' of the neuromatrix, that could be expressed functionally as anosognosia, giving rise to self-mutilation. We suggest that this self-mutilation is a pain consciousness problem.