Molecular characterization of metabolic diseases in which language impairment is a prominent symptom decisively contributes to a better understanding of the molecular effects and ontogenetic context on the development of the language organ. Main etiological feature in these diseases is actually diverse, as it may be disturbed in: 1) hormone homeostasis; 2) sugar, creatine, carnitine, lipid, sulphur, organic acid, or aminoacid metabolism; 3) different cellular processes (lysosomal storage and mitochondrial function). Metabolic disturbances ultimately lead to structural and functional anomalies in different brain regions, which positively correlate with the linguistic and cognitive impairments. Functional cloning has greatly helped to identify genes involved in such metabolic diseases, and so to a better understanding of the innate programme involved in the development of the linguistic module.
