Reference Values of Intraepidermal Nerve Fiber Density in Children and Small Fiber Neuropathy in Neurometabolic and Neurodevelopmental Disorders in Children

Background: Small-Fiber-Neuropathy describes the degeneration of mildly or unmyelinated nerve fibers and causes neuropathic pain and autonomic dysfunction. Gold standard for the diagnosis is a small skin punch biopsy from the lower leg and the histological quantification of the intraepidermal nerve fiber density (IENFD). In children, the normal IENFD has not been systematically assessed and normal reference values are needed. In Parkinson´s disease, the neurodegeneration also affects the peripheral nerves and SFN is present already in the early stages. Whether neurodevelopmental disorders (NDDs) in childhood are likewise associated with SFN is largely unknown. The IENFD is age-dependent and declines with age.Aims: In this study, we are establishing the reference values for the physiological IENFD in children from 0-18 years. Moreover, we are investigating if children with NDDs have a reduced IENFD and if SNF is a clinically relevant cause of pain and autonomic dysfunction.

control patientsInclusion Criteria:Elective surgical intervention from lower legInterest to participate in the study, informed consentUnremarkable neurological developmentExclusion Criteria:Clinical signs of polyneuropathy, autonomic dysfunctionSkin inflammation, scar, skin disease, other known chronic diseases that can cause small fiber pathologyNeurodevelopmental patientsInclusion Criteria:Neurodevelopmental problems (developmental delay, muscular hypotonia, seizures, ataxia,...) with age of onset before the age of 18 yearsInterest to participate in the study, informed consentExclusion Criteria:Known polyneuropathySkin inflammation, scar, skin disease, other known chronic diseases that can cause small fiber pathology