Since the publication of the initial case report in 1954 (1), seizures due to pyridoxine-dependency have been recognized as an uncommon cause of intractable seizures in neonates and infants. In the more than six decades since the first description of pyridoxine-dependent seizures, also known as pyridoxine-dependent epilepsy (PDE), more than 200 cases have been reported, with the majority of these publications appearing over the past 25 years focusing on atypical clinical presentations (2-5), neurodevelopmental features (6-9), electroencephalographic (EEG) characteristics (10-15), and imaging findings (6, 14, 16, 17). The most recent reports have focused on the biochemical abnormality underlying PDE, the associated mutations in the ALDH7A1 gene (8, 18-26), and the use of a lysine-restricted diet in managing patients with the disorder (27,28).
While neonatal seizures due to pyridoxine-dependency are felt to be quite rare, the reports of the late-onset and other atypical presentations (2-5) along with epidemiologic data from Europe (6, 29-31) suggest that this is a more common clinical entity than once thought.
In order to learn more about the variety of clinical presentations of PDE, the response of the disorder to various dosage regimens of pyridoxine, the imaging and EEG characteristics of the disorder, and the long term developmental consequences of PDE, we have developed a PDS Registry. Patients with PDE will be identified to the registry by physicians or parents. After informed consent, clinical and developmental data will be obtained and saved for future analysis and reporting. Other investigators interested in PDE may request to contact registered patients. These investigators will need to have a protocol approved by their institution’s "IRB". However, to protect confidentiality, outside investigators will not be able to directly contact registered patients. Parents who are interested in participating in other studies will be given the names of these researchers and the parents then may contact the investigators.
The Pyridoxine-Dependent Seizures Registry was first developed by the Child Neurology Service at University of California, Davis Medical Center in 1999 and then moved to the Division of Pediatric Neurology at Seattle Children’s Hospital and the University of Washington in Seattle in 2000. Between 1999-2007, 63 patients were registered and the findings of the initial analysis of this clinical data was published in 2009 (32).
In 2015, an international group of clinical researchers interested in PDE (the PDE Consortium) developed the “International PDE Registry, and information about this project may be found on the Consortium’s website: www.pdeonline.org
Since the 2009 publication (32), additional patients have been added to the Pyridoxine-Dependent Seizures Registry and follow-up information has been requested from previously registered patients. Importantly, during 2015 and 2016 it is planned that existing registry data (with the permission of the patients) will be migrated into the International PDE Registry, and all new patients wishing to be registered will then participate in the International PDE Registry.
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