Identification of PCDH19 Gene Mutations/Deletions in Patients with Early Onset Epilepsy

BACKGROUND AND AIMS: PCDH19 gene, which encodes protocadherin 19, is associated with epilepsy and intellectual disability, mainly in affected females. The clinical manifestations are heterogeneous and the main features include early onset seizure, generalized or focal seizures sensitive to fever, and brief seizures occurring in clusters. The disorders exhibit a unique and unusual X-linked pattern of expression. We aimed to investigate PCDH19 mutations/deletions in patients with epilepsy and describe the clinical/molecular features. METHODS: PCDH19 gene was analyzed in 35 Turkish female patients from 34 families with early-onset epilepsy via direct sequencing and multiplex ligation-dependent probe amplification analysis. Additionally, array comparative genomic hybridization analysis was performed in patients with whole gene deletion. RESULTS: We identified 2 different heterozygous mutations in 2 unrelated probands (5. 7%) which were located in exon 1. Additionally, whole gene deletions were detected in dizygotic twin girls (5. 7%), who had distinct clinical features and the deletion was inherited from the unaffected father. The second twin suffered more severe clinical manifestations including autistic features, behavioral problems, mild-moderate mental retardation and seizures, which were under control with multidrug regimen when compared with the first twin. CONCLUSION: PCDH19 is a major causative gene in patients with epilepsy and further data is required to gain a better understanding of phenotype-genotype correlation. In addition to gene sequencing, deletion/duplication analysis will improve the molecular diagnosis in patients with clinical findings.