Last update:
05-Aug-2017

The C9ORF72 gene encodes for a protein which is expressed at a high rate in the central nervous system, but whose role has not yet been clarified. In recent studies, the C9ORF72 gene has been linked to a significant number of neurodegenerative diseases. In particular, a dynamic mutation (GGGGCC hexanucleotide repeat expansion in the C9ORF72 gene) appears to be involved in the pathogenesis of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) and can also lead to Huntington's disease (HD)-like syndromes, Parkinsonian syndromes and Alzheimer's type dementia. This is a report of the genetic characteristics of the C9ORF72 gene, laboratory detection of the mutation, relevant genetic counseling, and specific clinical features of the mutation and the incidence of each disease in Greece and internationally. Information is provided here on the C9ORF72 gene involvement in the clinical presentation of Greek patients with dementia and motor neurodegenerative diseases studied at the Neurogenetics Unit of the "Eginition" Hospital, in comparison with data from other studies. It appears that the frequency of the C9ORF72 mutation in this Greek population with regard to ALS, FTD, Alzheimer's type dementia and HD-like conditions is in line with that reported in international studies. It is of note that the frequency of the C9ORF72 mutation in Greek ALS patients is among the highest in Europe and that this mutation is the most common genetic cause of HD-like syndromes in Greece.

Key words: C9ORF72 gene, Greek population, Neurodegenerative diseases.