Giant Axon Neuropathy (GAN) is a progressive neurodegenerative disease characterised by involvement of peripheral and central nervous system frequently associated with frizzy hair. The phenotype is caused by bi-allelic variants in the GAN gene, leading to loss of functional gigaxonin proteins.. Thus, far the disease cannot be cured, but a first clinical gene therapy trial in the US was currently completed. So far, there has been no systematic reporting of GAN patients in German-speaking countries. Therefore, we conducted a survey using an e-mail list of German-speaking child neurologists of the so-called DACH region reflecting Germany, Austria and Switzerland. Based on their feedback, clinical, genetic and epidemiological data were collected using a standardised data collection form in turn enabling the collection of comprehensive and detailed epidemiological, clinical and genetic information from a total of 15 patients representing one of the largest cohorts systematically described thus far. Average age of patients was 11.7 years at the time of data collection. In line with the frequency of homozygous variants, the majority were of Syrian origin and of consanguineous relationships. In 14 patients, diagnosis was confirmed by molecular genetics, revealing eight different GAN variants, four being reported as pathogenic in literature. 13 patients had a classical GAN phenotype, one was classified as mild whereas another one was too young to draw final clinical conclusions. Proteomics of white blood cells derived from four patients revealed was conducted to obtain unbiased insights into the underlying pathophysiology and revealed dysregulation of 111 proteins implicated in diverse biological processes. Of note diverse of these proteins are known to be crucial for proper synaptic function and transmission and affection of intermediate filament organization and proteolysis is in line with the known functions of gigaxonin. In view of a potential genetic treatment option, these data on the natural course of the disease are important for study design in preparation for gene therapy trials in Europe and moreover provide a catalogue of proteins serving as minimal invasive but cellular biomarkers.