Pyridoxine-dependent epilepsy (PDE) is a rare genetic disorder characterized by intractable seizures in the prenatal and neonatal period. The disorder was first recognized in the 1950s, with the first description provided by Hunt et al. in 1954. More recently, pathogenic variants within the ALDH7A1 gene have been identified to cause PDE. Genetics
PDE is inherited in an autosomal recessive manner and is estimated to affect around 1 in 400,000 to 700,000 births, though one study conducted in Germany estimated a prevalence of 1 in 20,000 births. The ALDH7A1 gene encodes for the enzyme antiquitin or α-aminoadipic semialdehyde dehydrogenase, which is involved with the catabolism of lysine. Treatment
Patients with PDE do not respond to anticonvulsant medications, but seizures rapidly cease with therapeutic intravenous doses of vitamin B6 and remission from seizures are often maintained on daily therapeutic doses of vitamin B6. An optimal dose has not yet been established, but doses of 50–100 mg/day or 15–30 mg/kg/day have been proposed. Importantly, excessive doses of vitamin B6 can result in irreversible neurological damage, and therefore several guidelines recommend between 200 mg (neonates) and 500 mg per day as the maximal daily dose.Despite remission of seizure activity with vitamin B6 supplementation, intellectual disability is frequently seen in patients with PDE. Because the affected enzyme antiquitin is involved in the cerebral lysine degradation pathway, lysine restriction as an additional treatment modality has recently been explored. Studies have been published which demonstrate potential for improved biomarkers, development, and behavior in patients treated with lysine restriction in addition to pyridoxine supplementation.
However, this is still considered controversial.If the papillary fibroelastoma is associated with symptoms, surgical excision is generally recommended for relief of symptoms. A minimally invasive approach may be possible if the tumor involves the aortic valve or right atrium. In the case of aortic valve involvement, excision of the tumor is often valve-sparing, meaning that replacement of the valve with a prosthetic valve is not necessary. Repair of the native valve with a pericardial patch has been described. See also
Endocardial fibroelastosis

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