West's syndrome (WS) is the most common infantile epileptic encephalopathy, although its frequency leads to its being included among the rare diseases (1:5,000). It is characterised by recurring crises called spasms, progressive psychomotor retardation and a typical EEG denominated hypsarrhythmia. It is due to mutations in the ARX gene, which codes for a homeobox transcription factor that is fundamental for the generation, migration and development of the GABAergic interneurons of the striated body, cerebral cortex and hippocampus. Animals which are mutant for ARX present a reduction in the number of interneurons in the said areas.

The majority of children with WS are refractory to pharmaceutical treatment, so they need a therapeutic alternative. This may be in the form of cell therapy, as the neurons that have disappeared can be replaced. Previous results of this group show that fetal neural progenitors derived from the middle ganglion eminence (MGE) differentiate into GABAergic interneurons after being implanted into the neonatal and adult brain. These progenitors are able to integrate fully within existing circuits, modulating inhibitory activity within the regions they are implanted in. This makes it possible to reduce hyperactivity levels, and they also have an anticonvulsive effect.

At the present time, a series of transplants has commenced with these neuronal precursors in an animal model which is a transporter of the (GCG)₁₀₊₇ mutation, the most frequent among WS patients. This model has studied the distribution, survival, differentiation and functionality of the cells deriving from transplant, as well as effects on the symptoms characterising this syndrome. It will also evaluate the potential and clinical interest of this type of cell therapy.