NAV1 and erythromelalgia: The absence of a clearer phenotypic distinction between the 2 groups is similar to a study in which erythromelalgia patients carrying the pathogenic NaV1.7 mutation I848T could not be phenotypically distinguished from those not carrying the mutation.67 The addition of suprathreshold QST paradigms might improve our ability to differentiate mechanistically relevant subgroups.32 Larger replication studies will be needed to determine whether these phenotypic aspects could be used in the future to stratify patients for potential genetic testing.