Aetiology of childhood apraxia of speech: A clinical practice update for paediatricians

Childhood apraxia of speech (CAS) is a rare disorder of childhood that can leave a watermark of the impacts throughout the lifetime. Since being first described in the 1950s, aetiological insights have been limited. At a neurobiological level, clinical MRI scans fail to reveal overt neural anomalies in individual cases with CAS, although quantitative MRI methods have revealed subtle brain anomalies at a group level. Dramatic insights, however, occurred in the past decade from the discovery of genetic pathways underlying the phenotype. Several single genes and copy number-variant conditions are now associated with CAS either in relative isolation, as in the case of FOXP2 variants, or most typically in association with other neurodevelopmental conditions, such as epilepsy, intellectual disability, motor impairment and autism. CAS requires careful differential diagnosis from other childhood speech disorders, but when a severe and persistent diagnosis is confirmed, a genetic aetiology should increasingly be pursued.