SLC1A3 variant associated with hemiplegic migraine and acetazolamide-responsive MRS changes.

Familial hemiplegic migraine (FHM) is a group of rare familial disorders caused, in most cases, by mutations in CACNA1A and ATP1A2.(1) Heterozygous mutations in solute carrier family 1 member 3 (SLC1A3), encoding glial glutamate transporter, are associated with episodic ataxia type 6 (EA6).(2-5) In addition to episodic ataxia (EA), alternating hemiplegia and hemiplegic migraine have been reported twice in patients with EA6.(2,4) Mutations in SLC1A3 are very rare; screenings in cohorts of EA and alternating hemiplegia have yielded either negative results(3,6-8) or variants of unclear significance.(e-1--e-3) Herein, we characterize a patient featuring sporadic hemiplegic migraine (SHM) responsive to acetazolamide (ACZ) and mild cerebellar atrophy associated with a new variant in SLC1A3. We also report the utility of proton magnetic resonance spectroscopy (MRS) for this condition.