Variability of Phenotype in Two Sisters with Pyridoxine Dependent Epilepsy

Genotype and phenotype features and prognostic factors of neonatal-onset pyridoxine-dependent epilepsy: A systematic review

Pyridoxine-dependent epilepsy (PDE-ALDH7A1) is a rare autosomal recessive disorder due to a deficiency of α-aminoadipic semialdehyde dehydrogenase. This study aimed to systematically explore genotypic and phenotypic features and prognostic factors of neonatal-onset PDE. A literature search covering PubMed, Elsevier, and Web of Science was conducted from January 2006 to August 2023. We identified 56 eligible studies involving 169 patients and 334 alleles. The c.1279 G>C variant was the most common variant of neonatal-onset PDE (25.7 %). All patients were treated with pyridoxine; forty patients received dietary intervention therapy. 63.9 % of the patients were completely seizure-free; however, 68.6 % of the patients had neurodevelopmental delays. Additionally, homozygous c.1279 G>C variants were significantly associated with ventriculomegaly, abnormal white matter signal, and cysts (P<0.05). In contrast, homozygous c.1364 T>C was associated with clonic seizure (P=0.031). Pyridoxine used immediately at seizure onset was an independent protective factor for developmental delay (P=0.035; odds ratio [OR]: 3.14). Besides, pyridoxine used early in the neonatal period was a protective factor for language delay (P=0.044; OR: 4.59). In contrast, neonatal respiratory distress (P=0.001; OR: 127.44) and abnormal brain magnetic resonance imaging (P=0.049; OR: 3.64) were risk factors. Prenatal movement abnormality (P=0.041; OR: 20.56) and abnormal white matter signal (P=0.012; OR: 24.30) were risk factors for motor delay. Myoclonic seizure (P=0.023; OR: 7.13) and status epilepticus (P=0.000; OR: 9.93) were risk factors for breakthrough seizures. In conclusion, our study indicated that pyridoxine should be started immediately when unexplained neonatal seizures occur and not later than the neonatal period to prevent poor neurodevelopmental outcomes.

PYRIDOXINE-dependent epilepsy (PDE): An observational study of neonatal cases on the role of pyridoxine in patients treated with standard anti-seizure medications

BACKGROUND

The main objective of this study was to evaluate the neurological consequences of delayed pyridoxine administration in patients diagnosed with Pyridoxin Dependent Epilepsies (PDE).

MATERIALS AND METHODS

We reviewed 29 articles, comprising 52 genetically diagnosed PDE cases, ensuring data homogeneity. Three additional cases were included from the General Pediatric Operative Unit of San Marco Hospital. Data collection considered factors like age at the first seizure's onset, EEG reports, genetic analyses, and more. Based on the response to first-line antiseizure medications, patients were categorized into four distinct groups. Follow-up evaluations employed various scales to ascertain neurological, cognitive, and psychomotor developments.

RESULTS

Our study includes 55 patients (28 males and 27 females), among whom 15 were excluded for the lack of follow-up data. 21 patients were categorized as "Responder with Relapse", 11 as "Resistant", 6 as "Pyridoxine First Approach", and 2 as "Responders". The neurological outcome revealed 37,5 % with no neurological effects, 37,5 % showed complications in two developmental areas, 15 % in one, and 10 % in all areas. The statistical analysis highlighted a positive correlation between the time elapsed from the administration of pyridoxine after the first seizure and worse neurological outcomes. On the other hand, a significant association was found between an extended latency period (that is, the time that elapsed between the onset of the first seizure and its recurrence) and worse neurological outcomes in patients who received an unfavorable score on the neurological evaluation noted in a subsequent follow-up.

CONCLUSIONS

The study highlights the importance of early recognition and intervention in PDE. Existing medical protocols frequently overlook the timely diagnosis of PDE. Immediate administration of pyridoxine, guided by a swift diagnosis in the presence of typical symptoms, might improve long-term neurological outcomes, and further studies should evaluate the outcome of PDE neonates promptly treated with Pyridoxine.

Update on the treatment of vitamin B6 dependent epilepsies

Introduction: Vitamin B6 dependent epilepsies are a group of treatable diseases (ALDH7A1 deficiency, PNPO deficiency, PLP binding protein deficiency, hyperprolinaemia type II and hypophosphatasia and glycosylphosphatidylinositol anchor synthesis defects) responding to pyridoxine or pyridoxal-5^I-phosphate. Areas covered: A critical review was conducted on the therapeutic management of all the reported patients with genetically confirmed diagnoses of diseases affecting vitamin B6 metabolism and presenting with pyridoxine or pyridoxal-5^I-phosphate dependent-seizures. Data about safety and efficacy were analyzed as well as the management of supplementation with pyridoxine or pyridoxal-5^I-phosphate both in the acute phases and in the maintenance therapies. The authors also analyzed alternative therapeutic strategies for ALDH7A1 deficiency (lysine-restricted diet, arginine supplementation, oligonucleotide antisense therapy, upstream inhibition of aminoadipic semialdehyde synthase). Expert opinion: The administration of pyridoxine or pyridoxal-5^I-phosphate should be considered in all intractable seizures also beyond the first year of life. Lysine restricted diet and arginine supplementation should be introduced in all the confirmed ALDH7A1 deficient patients. Pre or post-natal supplementation with pyridoxine should be given in familial cases until an eventual molecular genetic disconfirmation. Minor data about alternative therapies are available for other disorders of vitamin B6 metabolism.

Pyridoxine-Dependent Epilepsy: An Expanding Clinical Spectrum

BACKGROUND

Pyridoxine-dependent epilepsy is a rare autosomal recessive epileptic encephalopathy caused by antiquitin (ALDH7A1) deficiency. In spite of adequate seizure control, 75% of patients suffer intellectual developmental disability. Antiquitin deficiency affects lysine catabolism resulting in accumulation of α-aminoadipic semialdehyde/pyrroline 6' carboxylate and pipecolic acid. Beside neonatal refractory epileptic encephalopathy, numerous neurological manifestations and metabolic/biochemical findings have been reported.

METHODS AND RESULTS

We present a phenotypic spectrum of antiquitin deficiency based on a literature review (2006 to 2015) of reports (n = 49) describing the clinical presentation of confirmed patients (n > 200) and a further six patient vignettes. Possible presentations include perinatal asphyxia; neonatal withdrawal syndrome; sepsis; enterocolitis; hypoglycemia; neuroimaging abnormalities (corpus callosum and cerebellar abnormalities, hemorrhage, white matter lesions); biochemical abnormalities (lactic acidosis, electrolyte disturbances, neurotransmitter abnormalities); and seizure response to pyridoxine, pyridoxal-phosphate, and folinic acid dietary interventions.

DISCUSSION

The phenotypic spectrum of pyridoxine-dependent epilepsy is wide, including a myriad of neurological and systemic symptoms. Its hallmark feature is refractory seizures during the first year of life. Given its amenability to treatment with lysine-lowering strategies in addition to pyridoxine supplementation for optimal seizure control and developmental outcomes, early diagnosis of pyridoxine-dependent epilepsy is essential. All infants presenting with unexplained seizures should be screened for antiquitin deficiency by determination of α-aminoadipic semialdehyde/pyrroline 6' carboxylate (in urine, plasma or cerebrospinal fluid) and ALDH7A1 molecular analysis.

Long-Term Follow-up of a Successfully Treated Case of Congenital Pyridoxine-Dependent Epilepsy

Autosomal recessive disorders affecting pyridoxine (vitamin B6) metabolism are a rare but well-recognized cause of neonatal seizures. Antiquitin deficiency, caused by mutations in ALDH7A1, is a disorder of the lysine degradation pathway causing accumulation of an intermediate that complexes with pyridoxal phosphate. Reports of long-term follow-up of neonatal pyridoxine-dependent seizures (PDS) remain scarce and prognostic information is varied. We report a case of PDS in a 47-year-old lady who originally presented shortly after birth in 1964. Pyridoxine replacement was successful and diagnostic confirmation was obtained later in life, initially by biochemical analysis of serum pipecolic acid. Subsequently we organized genetic analysis of ALDH7A1, which revealed compound heterozygous mutations. To our knowledge, this represents the longest duration of follow-up published to date.