SOX5 and developmental and speech delay due to SOX5 deficiency: Lamb-Shaffer syndrome (LAMSHF) is a rare autosomal dominant neurodevelopmental disorder caused by haploinsufficiency of the SOX5 gene on chromosome 12p12.1 and characterized by global developmental delay, intellectual disability, speech and language impairment, and frequent behavioral disturbances, including autistic traits and attention deficits.