An Italian family with familial hemiplegic migraine (FHM) with the absence of mutations in the known genes associated with this disorder, namely , , , and , has recently been reported. Soon afterward, whole exome sequencing allowed the identification of the carrier status of a heterozygous mutation c.1798 C >T, in four affected members of this family. Here we compare the clinical symptoms of the affected family members with those from the other FHM families linked to mutations in the known genes associated with this disorder. A further two-year follow-up, including clinical response to carbamazepine administered to the proband and the maternal grandmother due to a worsening of the migraine symptoms, is reported. The clinical condition of the proband's brother, carrying the same mutation and suffering from congenital ventricular and supraventricular extrasystoles, isdiscussed as well.