However, while mutations in FOXP2 lead to a speech/language disorder characterized by childhood apraxia of speech (CAS), the clinical profile of FOXP1 variants includes a broader neurodevelopmental phenotype with global developmental delay, intellectual disability, and speech/language impairment.
An emerging phenotype of patients with protein-disrupting FOXP1 variants includes global developmental delay, intellectual disability and mild to severe speech/language deficits.
Mutations in FOXP1, located at 3p13, have been reported in patients with global developmental delay (GDD), intellectual disability (ID), and speech defects.