Lamb-Shaffer syndrome (LAMSHF, OMIM 616803) is a rare autosomal dominant neurodevelopmental disorder caused by heterozygous loss-of-function variants or microdeletions involving the SOX5 gene at chromosome 12p12.1 [1-3]. Clinical characterization from recent case series demonstrates a consistent phenotype of global developmental delay, mild-to-moderate intellectual disability, prominent expressive language impairment, mild facial dysmorphism, and behavioral disturbances, including autistic features, hyperactivity, and emotional dysregulation [1-3]. The gene discussed is SOX5; the disease is Lamb-Shaffer syndrome.