ABSTRACT
【Objective】 To analyze the clinical features and gene mutation characteristics of four children with pyridoxine-dependent epilepsy (PDE) in order to provide evidence for early diagnosis of this rare disease. 【Methods】 The clinical data of four cases of PDE were collected from January 2016 to June 2019 in The Second Affiliated Hospital of Xi’an Jiaotong University. We collected data of the laboratory examination, electroencephalogram, and magnetic resonance imaging (MRI). Peripheral venous blood was collected from children and parents, genomic DNA was extracted from white blood cells, and primers were designed to amplify the aldehyde dehydrogenase 7 family member A1(ALDH7A1) on the long arm of chromosome 5 using PCR; exon and the junction of exon and intron were also amplified to determine whether there is a gene mutation. 【Results】 All the 4 cases had a full-term birth and no history of birth asphyxia. ① Clinical features: onset time from 8 days after birth to 6 months after birth. Type of seizure: 1 case with myoclonus onset, then converted to spasm; 1 case for generalized seizures; 2 cases for partial seizures, then converted to generalized seizures; 3 cases were prone to epileptic seizures; 1 case was significantly worse after infection; MRI: 3 cases showed no abnormalities, 1 case showed non-specific abnormalities; EEG: One case was fragmentary hypsarrhythmia, 3 cases of multifocal epileptiform discharge; Treatment: a small dose of vitamin B6 could control the seizure, 1 of them was controlled at a tiny dose, and 3 cases were controlled by a small dose. ② Genetic analysis results: There were 4 cases of ALDH7A1 gene mutation, of which 3 cases were known gene mutations and 1 case was new mutation. 【Conclusion】 PDE has an early onset, often in the neonatal or small infancy, is prone to epilepticus and has an increased severity after infection. There is no specificity in seizure type, EEG or MRI. The analysis of ALDH7A1 gene and vitamin B6 load test can help to confirm the diagnosis, small dose of Vitamin B6 can control the seizures so as to provide reference for the dose of vitamin B6. However, the number of cases is small, and a large sample size is still needed for verification.