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Genotype-phenotype correlates of infantile-onset developmental & epileptic encephalopathy syndromes in South India: A single centre experience

Mitta, N; Menon, RN; McTague, A; Radhakrishnan, A; Sundaram, S; Cherian, A; Madhavilatha, GK; ... Thomas, SV; + view all (2020) Genotype-phenotype correlates of infantile-onset developmental & epileptic encephalopathy syndromes in South India: A single centre experience. Epilepsy Research , 166 , Article 106398. 10.1016/j.eplepsyres.2020.106398. Green open access

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Abstract

INTRODUCTION: A paucity of literature exists on genotype- phenotype correlates of 'unknown-etiology' infantile-onset developmental-epileptic encephalopathies (DEE) from India. The primary objective was to explore the yield of genetic testing in identifying potential disease causing variants in electro-clinical phenotypes of DEE METHODS: An observational hospital-based study was undertaken on children with unexplained refractory seizure-onset ≤12 months age and developmental delay, whose families consented and underwent genetic testing during a three year time period (2016-2018) by next-generation sequencing (NGS) or multiplex ligand protein amplification. Yield was considered based on demonstration of pathogenic/likely pathogenic variants only and variants of unknown significance (VUS) were documented. RESULTS: Pathogenic/likely pathogenic variants were identified in 26 (31.7 %) out of 82 children with DEE. These included those variants responsible for primarily DEE- 21(76.7 %); neuro-metabolic disorders- 3(18.6 %) and chromosomal deletions- 2(4.7 %). Of these patients, early-infantile epilepsy onset ≤ 6 months age was noted in 22(84.6 %). The DEE studied included Ohtahara syndrome associated with STXBP1 and SCN8A variants with yield of 50 % (2/4 tested); early myoclonic encephalopathy (no yield in 2); West syndrome with CDKL5, yield of 13.3 % (2/15 tested); epilepsy of infancy with migrating partial seizures due to CACNA1A and KCNT1 variants, yield of 67 % (2/3 tested); DEE-unclassified with KCNQ2, AP3B2, ZEB2, metabolic variants (SUOX, ALDH7A1, GLDC) and chromosome deletions (chr 1p36, chr2q24.3); yield of 32 % (8/25 tested). Patients with Dravet syndrome/Dravet-like phenotypes (N = 33) had variants in SCN1A (N = 10), SCN1B, CHD2; yield of 36.4 % (12/33 tested; 57.1 % from NGS). Eighteen patients with potential variants (SCN1A, SCN2A, SCN8A, KCNQ2, ALDH7A1 which also included VUS) could be offered targeted therapy. CONCLUSIONS: Our study confirms a good yield of genetic testing in neonatal and infantile-onset DEE provided robust phenotyping of infants is attempted with prognostic and therapeutic implications, particularly relevant to centres with resource constraints.

Type: Article
Title: Genotype-phenotype correlates of infantile-onset developmental & epileptic encephalopathy syndromes in South India: A single centre experience
Location: Netherlands
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.eplepsyres.2020.106398
Publisher version: https://doi.org/10.1016/j.eplepsyres.2020.106398
Language: English
Additional information: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Developmental & epileptic encephalopathy, Electro-clinical syndromes, Genetics, Next generation sequencing, Variants
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > UCL GOS Institute of Child Health
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > UCL GOS Institute of Child Health > Developmental Neurosciences Dept
URI: https://discovery.ucl.ac.uk/id/eprint/10111246
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