*2.5.4 Treatment and its outcome*

Seizures typically respond well to vitB6 treatment (PN in majority of cases). In cases with inadequate response to PN, switching to PLP led to better seizure control [67]. About half of the cases required additional anti-seizure medications for optimal seizure control [7, 67]. The addition of folinic acid resulted in improved seizure control in one patient [68].

While seizures and secondary metabolic alterations are usually normalized with vitB6 therapy, a major fraction of patients still develop some form of neurodevelopmental disability. A recent review of 45 published PLPHP deficiency cases found that 65% of the patients suffered from intellectual disability [67]. The underlying pathophysiological mechanism is not well understood, and currently there is no effective treatment against the neurodevelopmental phenotype of this disorder.
