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 results3,6–8 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. The authors are grateful to the patients for their kind participation in this study. They thank Dr. Mattias Andreasson for evaluating the index case during a hemiplegic spell.