Here, the pathogenesis of an IFIH1 gene mutation is discussed through the analysis of a sporadic case of hereditary spastic paraplegia. Next-generation sequencing was performed for the patient and his family members to detect mutations at the IFIH1 locus. The patient and his father were found to carry the same heterozygous missense mutation (c.1093A > G; p.Gly495Arg), while the patient\'s mother does not carry this mutation. This is the first report of this heterozygous IFIH1 mutation and it is predicted to be disease-causing.