Variants in CLDN5 cause a syndrome characterized by seizures, microcephaly and brain calcifications.
Brain : a journal of neurology 2022
Deshwar AR, Cytrynbaum C, Murthy H, Zon J, Chitayat D, Volpatti J, Newbury-Ecob R, Ellard S, Lango Allen H, Yu EP, Noche R, Walker S, Scherer SW, Mahida S, Elitt CM, Nicolas G, Goldenberg A, Saugier-Veber P, Lecoquierre F, Dabaj I, Meddaugh H, Marble M, Keppler-Noreuil KM, Drayson L, Barañano KW, Chassevent A, Agre K, Létard P, Bilan F, Le Guyader G, Laquerrière A, Ramsey K, Henderson L, Brady L, Tarnopolsky M, Bainbridge M, Friedman J, Capri Y, Athayde L, Kok F, Gurgel-Giannetti J, Ramos LLP, Blaser S, Dowling JJ, Weksberg R
DOI : 10.1093/brain/awac461
PubMed ID : 36477332
The blood brain barrier ensures central nervous system homeostasis and protection from injury. Claudin-5 (CLDN5), an important component of tight junctions, is critical for the integrity of the BBB. We have identified de novo heterozygous missense variants in CLDN5 in fifteen unrelated patients who presented with a shared constellation of features including developmental delay, seizures (primarily infantile onset focal epilepsy), microcephaly and a recognizable pattern of pontine atrophy and brain calcifications. All variants clustered in one subregion/domain of the CLDN5 gene and the recurrent variants demonstrate genotype-phenotype correlations. We modeled both patient variants and loss of function alleles in the zebrafish to show that the variants analogous to those in patients likely result in a novel aberrant function in CLDN5. In total, human patient and zebrafish data provide parallel evidence that pathogenic sequence variants in CLDN5 cause a novel neurodevelopmental disorder involving disruption of the blood brain barrier and impaired neuronal function.