An international consortium has recently characterized 18 individuals with biallelic CRELD1 variants who displayed a wide range of phenotypes, including developmental delay, early-onset epilepsy and hypotonia.20 However, because of the experimental strategy relying on the Xenopus tadpole, the study did not provide a comprehensive modelling and phenotypic characterization of the exact compound variants found in the patients. Here, CRELD1 is linked to Global developmental delay.