By combining next-generation sequencing and model organism research, researchers have pinpointed the pathogenic variant responsible for an extremely rare neurodevelopmental X-linked disorder that causes small head size (microcephaly) and growth retardation in three affected males of one family. After locating the candidate mutation in the X-chromosomal RPL10 gene, which encodes the 60S ribosomal protein L10, the team found that suppression of rpl10 expression in zebrafish recapitulated the human phenotype of microcephaly owing to reduced translation and increased apoptosis in the brain.