Exploring the genetic landscape of diphtheria, tetanus and pertussis vaccination-associated seizures or subsequent epilepsies.

Background: Diphtheria, Tetanus, and whole-cell Pertussis (DTwP) vaccination-associated seizures form the commonest type of serious adverse event following immunization in India and are an important reason for vaccine hesitancy. Our study explored the genetic explanation of DTwP vaccination-associated seizures or subsequent epilepsies. Methods: Between March 2017 and March 2019, we screened 67 children with DTwP vaccination-associated seizures or subsequent epilepsies, and of those, we studied 54 without prior seizures or neurodevelopmental deficits. Our study design was cross-sectional with a 1-year follow-up having both retrospective and prospective cases. We performed clinical exome sequencing focused on 157 epilepsy-associated genes and multiplex ligation-dependent probe amplification of the Findings: Of 54 children enrolled and underwent genetic testing (median age 37.5 months, interquartile range 7.7-67.2; diagnosis at enrolment: epilepsy 29, febrile seizure 21, and febrile seizure-plus 4), we found 33 pathogenic variants of 12 genes. Of 33 variants, 13 (39%) were novel. Most pathogenic variants were found in Interpretation: Our study provides proof-of-concept for genetic aetiology in children with DTwP vaccination-associated seizures or subsequent epilepsies and has important implications for vaccination policies in developing countries. Funding: International Pediatric Association Foundation, Inc. (IPAF): İhsan Doğramaci research award 2016/2017; Indian Council of Medical Research (ICMR), New Delhi, India: No.3/1/3/JRF-2016/HRD/LS/71/10940.