The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.
|Signs and Symptoms||Approximate number of patients (when available)|
|Abnormality of metabolism/homeostasis||90%|
|Abnormality of movement||90%|
|Neurological speech impairment||90%|
|Cerebral cortical atrophy||7.5%|
|Autosomal recessive inheritance||-|
|Delayed speech and language development||-|
|Generalized myoclonic seizures||-|
|Generalized tonic-clonic seizures||-|
|Neonatal respiratory distress||-|
|Prenatal movement abnormality||-|
Mutations in the ALDH7A1 gene cause pyridoxine-dependent epilepsy. This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
The ALDH7A1 gene provides instructions for making an enzyme called α-aminoadipic semialdehyde (α-AASA) dehydrogenase, also known as antiquitin. This enzyme is involved in the breakdown of the protein building block (amino acid) lysine in the brain.
When antiquitin is deficient, a molecule that interferes with vitamin B6 function builds up in various tissues. Pyridoxine plays a role in many processes in the body, such as the breakdown of amino acids and the productions of chemicals that transmit signals in the brain (neurotransmitters). It is unclear how a lack of pyridoxine causes the seizures that are characteristic of this condition.
Some individuals with pyridoxine-dependent epilepsy do not have identified mutations in the ALDH7A1 gene. In these cases, the cause of the condition is unknown.
Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.
Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.
Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.
These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.
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My daughter was diagnosed with pyridoxine-dependent epilepsy at birth. Her symptoms were controlled until a few years ago when she began to have muscle stiffness in the hands and legs, partial seizures, and loss of her voice. Her seizures now occur almost daily and are quite violent. Her doctors believe that her seizure activity may now be the result of psychogenic nonepileptic seizures (PNES). Is this a common occurrence in adults with pyridoxine-dependent epilepsy? See answer