SLC7A6OS Founder Mutation: A Rare Cause of Progressive Myoclonus Epilepsy Dated to 1100 Years Ago
BACKGROUND: SLC7A6OS c.191A>G is a rare, autosomal recessive cause of progressive myoclonus epilepsy (PME). The c.191A>G variant, first discovered in two families from Türkiye and Portugal, was recently identified in three additional probands from the USA, all of Puerto Rican ancestry. OBJECTIVES: We sought to refine the SLC7A6OS-PME phenotype and determine whether all families inherited the variant from the same common ancestor. METHODS: Clinical and genotyping data were obtained from all five families. Haplotype analysis using single nucleotide polymorphism arrays to investigate a possible common ancestor was performed. RESULTS: Shared haplotypes suggest all five families inherited the SLC7A6OS variant from a common ancestor approximately 1100 years ago. Subsequent dating estimates were consistent with migration patterns between the eastern Mediterranean, Iberia, and Puerto Rico. CONCLUSIONS: Our findings strengthen the previous evidence for SLC7A6OS as a cause of PME and highlight a founder effect in regions with migratory links to Iberia. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
Authors
- Krystal Sully (ORCID: https://orcid.org/0000-0003-0137-7080)
- Mered Parnes (ORCID: https://orcid.org/0000-0003-2102-4282)
- Karen Oliver (ORCID: https://orcid.org/0000-0001-5188-6153)
- Nerses Bebek (ORCID: https://orcid.org/0000-0002-4749-1471)
- Bronwyn E. Grinton (ORCID: https://orcid.org/0000-0003-4880-2486)
- Colin A. Ellis (ORCID: https://orcid.org/0000-0003-2152-8106)
- Anna‐Elina Lehesjoki (ORCID: https://orcid.org/0000-0003-4014-3113)
- Sara Cabet (ORCID: https://orcid.org/0000-0003-0115-2586)
- Volkan Taşdemir (ORCID: https://orcid.org/0000-0003-2467-1565)
- Gaëtan Lesca (ORCID: https://orcid.org/0000-0001-7691-9492)
- Laure Mazzola (ORCID: https://orcid.org/0000-0001-7307-0809)
- Samuel F. Berkovic (ORCID: https://orcid.org/0000-0003-4580-841X)
- Melanie Bahlo (ORCID: https://orcid.org/0000-0001-5132-0774)
- Mariam Hull (ORCID: https://orcid.org/0000-0002-7340-1660)
- Jacob E. Munro (ORCID: https://orcid.org/0000-0002-2751-0989)
- Laina Lusk (ORCID: https://orcid.org/0000-0001-9799-9890)
- Betül Baykan (ORCID: https://orcid.org/0000-0002-3360-659X)
- Pamela Pojomovsky McDonnell (ORCID: https://orcid.org/0000-0003-3474-6428)
Institutions
- Université Claude Bernard Lyon 1 (FR)
- Centre National de la Recherche Scientifique (FR)
- Children's Hospital of Philadelphia (US)
- University of Helsinki (FI)
- Inserm (FR)
- The University of Melbourne (AU)
- Lyon College (US)
- Walter and Eliza Hall Institute of Medical Research (AU)
- Centre de Recherche en Neurosciences de Lyon (FR)
- Hospices Civils de Lyon (FR)
- Institut NeuroMyoGène (FR)
- Texas Children's Hospital (US)
- Centre Hospitalier Universitaire de Saint-Étienne (FR)
- Austin Health (AU)
- Folkhälsans Forskningscentrum (FI)
- Istanbul University (TR)
- University of Pennsylvania (US)
Publication Details
- Journal
- Movement Disorders
- Published
- 2026-09-18
- DOI
- https://doi.org/10.1002/mds.70516
- Primary Topic
- Glycogen Storage Diseases and Myoclonus
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Health and Medical Research Council
- National Institute of Neurological Disorders and Stroke