Two novel families with hemiplegic migraine caused by recurrent SCN1A mutation p.F1499L.

Authors

Schubert V1, Auffenberg E1, Biskup S2, Jurkat-Rott K3, Freilinger T1.
  1. Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
  2. Praxis für Humangenetik Tübingen, Tübingen, Germany.
  3. Division of Neurophysiology, Ulm University, Ulm, Germany.

Abstract

Background Familial hemiplegic migraine type 3 is a monogenic subtype of migraine caused by missense mutations in the neuronal voltage-gated sodium channel gene SCN1A, with 10 different mutations reported so far. In two familial hemiplegic migraine type 3 families, partial cosegregation with a rare eye phenotype (elicited repetitive daily blindness) was previously reported. Methods Two novel familial hemiplegic migraine pedigrees were subjected to genetic analysis and detailed work-up of associated clinical features. Results In both pedigrees, we identified SCN1A mutation p.F1499L, which has been previously associated with familial hemiplegic migraine type 3 and elicited repetitive daily blindness. Both families displayed a pure familial hemiplegic migraine phenotype without evidence of an episodic eye phenotype. Conclusion Like a substantial proportion of other familial hemiplegic migraine type 3 mutations, p.F1499L affects the intracellular linker between domains III and IV of SCN1A, which seems to be a mutational hot-spot. Our new data establish p.F1499L as a recurrent familial hemiplegic migraine type 3 mutation. Elicited repetitive daily blindness seems to be a rare phenomenon in familial hemiplegic migraine type 3, even in carriers of the same mutation.