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ATP6V1B2 ‐related epileptic encephalopathy
Author(s) -
Inuzuka Luciana Midori,
MacedoSouza Lúcia Inês,
DellaRippa Bruno,
Monteiro Fabiola Paoli,
Delgado Daniel de Souza,
Godoy Luis Filipe,
Ramos Luiza,
Athayde Costa Larissa Sampaio,
Garzon Eliana,
Kok Fernando
Publication year - 2020
Publication title -
epileptic disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.673
H-Index - 53
eISSN - 1950-6945
pISSN - 1294-9361
DOI - 10.1684/epd.2020.1166
Subject(s) - microcephaly , epilepsy , exome sequencing , intellectual disability , west syndrome , encephalopathy , phenotype , genetics , loss function , biology , medicine , gene , neuroscience
ATP6V1B2 encodes a subunit of the lysosomal transmembrane proton pump necessary for adequate functioning of several acid hydrolases. De novo monoallelic variants of this gene have been associated with two distinct phenotypes: Zimmermann‐Laband syndrome 2 (ZLS2), an intellectual deficiency/multiple malformation syndrome, and dominant deafness onychodystrophy (DDOD), a multiple malformation syndrome without cognitive involvement. Epilepsy is not observed in DDOD, is variably present in ZLS2, but is a common feature in Zimmermann‐Laband syndrome 1 (ZLS1) (caused by monoallelic pathogenic variants in KCNH1 ) and Zimmermann‐Laband syndrome‐like (ZLSL) (associated with KCNK4 variants). Herein, we report a case of an infant with severe epileptic encephalopathy with microcephaly and profound developmental delay, associated with a novel de novo loss‐of‐function variant in ATP6V1B2 , diagnosed by whole‐exome sequencing. This finding expands the spectrum of ATP6V1B2 ‐associated disorders and adds ATP6V1B2 as a new member for the growing list of early‐onset epileptic encephalopathy genes. [ Published with video sequence ].