Families on three continents inherited their epilepsy from a single person
A single individual who lived centuries ago was the source of a genetic mutation linked to a rare form of childhood epilepsy1.
The condition, called genetic epilepsy with febrile seizures plus (GEFS+), causes childhood seizures and often affects multiple generations of one family. Past research shows that at least six unrelated GEFS+ families all harbour the same variant of the gene SCN1B.
Bronwyn Grinton at the University of Melbourne, Australia, and her colleagues analysed the genes of 14 families with this variant in Australia, the United Kingdom and the United States. The team then reconstructed a set of genetic mutations surrounding the SCN1B variant that are unassociated with GEFS+ but tend to be inherited together as a ‘haplotype’. Modelling suggests that all 14 families are descended from a carrier of this haplotype who lived about 800 years ago.
The haplotype appears more frequently in a UK biological database than in an international one, indicating that the SCN1B variant arose in Britain. The authors say GEFS+ has probably persisted in the population for centuries because of its mild symptoms, which usually resolve by the age of six.
doi: https://doi.org/10.1038/d41586-022-03383-3
References
Grinton, B. E. et al. Am. J. Hum. Genet. https://doi.org/10.1016/j.ajhg.2022.10.004 (2022).
