Edition of 03 August 2023

A new study published in the Brain identified variants in CLDN5 (Claudin-5, an important component of tight junctions, critical for the integrity of the blood–brain barrier), within 15 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. Zebrafish model shows that the variants analogous to those in patients probably result in a novel aberrant function in CLDN5, and provides parallel evidence for the aetiology of a novel neurodevelopmental disorder involving disruption of the blood–brain barrier and impaired neuronal function.