Expanding the clinical and genetic spectrum of CAD deficiency: an epileptic encephalopathy treatable with uridine supplementation.

PURPOSE: Biallelic CAD variants underlie CAD deficiency (or early infantile epileptic encephalopathy-50, [EIEE-50]), an error of pyrimidine de novo biosynthesis amenable to treatment via the uridine salvage pathway. We further define the genotype and phenotype with a focus on treatment. METHODS: Retrospective case series of 20 patients. RESULTS: Our study confirms CAD deficiency as a progressive EIEE with recurrent status epilepticus, loss of skills, and dyserythropoietic anemia. We further refine the phenotype by reporting a movement disorder as a frequent feature, and add that milder courses with isolated developmental delay/intellectual disability can occur as well as onset with neonatal seizures. With no biomarker available, the diagnosis relies on genetic testing and functional validation in patient-derived fibroblasts. Underlying pathogenic variants are often rated as variants of unknown significance, which could lead to underrecognition of this treatable disorder. Supplementation with uridine, uridine monophosphate, or uridine triacetate in ten patients was safe and led to significant clinical improvement in most patients. CONCLUSION: We advise a trial with uridine (monophosphate) in all patients with developmental delay/intellectual disability, epilepsy, and anemia; all patients with status epilepticus; and all patients with neonatal seizures until (genetically) proven otherwise or proven unsuccessful after 6 months. CAD deficiency might represent a condition for genetic newborn screening.

Seizure Freedom in Patients with Dravet Syndrome with Contraceptives: A Case Report with Two Patients.

Dravet syndrome is a rare and malignant epileptic syndrome that is typically resistant to antiepileptic drugs. There is a growing interest in the antiepileptic properties of neurosteroids. Especially progesterone is known to act as an anticonvulsive agent. However, contraceptives that act as orally given neurosteroids often lead to increased seizures in women with epilepsy.We report on two girls with Dravet syndrome, who gained seizure freedom under therapy with contraceptives. The first patient received an oral contraceptive, a combination of an estrogen, and a gestagen, due to hypermenorrhea. The second received a pure gestagen implant for contraception.The antiepileptic effect of progesterone is mainly attributed to its conversion into allopregnanolone and related neurosteroids, which are positive modulators of gamma-aminobutyric acid A receptors. It is unclear whether the observed effect of these contraceptives containing synthetic progesterone derivatives may be specific for the Dravet syndrome, and it is unclear whether and how this observation can be used therapeutically.

Bromide in patients with SCN1A-mutations manifesting as Dravet syndrome.

We report a retrospective analysis of bromide therapy in 32 patients suffering from Dravet syndrome with SCN1A-mutations who received bromide. After 3 months of bromide treatment, 26 patients (81%) showed a relevant improvement with a reduction of seizure frequency by >50% (>75%) in 18 (12) patients (56 and 37%, respectively). After 12 months, we observed a reduction of >50% (>75%) in 15 (9) patients (47 and 28%, respectively). Long-term response was noted in 18 patients (56%). Adverse reactions were mainly mild or moderate leading to treatment termination in 5/32 patients; no aggravation was reported. We conclude that bromide holds promise in patients with SCN1A-mutations suffering from Dravet syndrome.

A retrospective study of the relation between vaccination and occurrence of seizures in Dravet syndrome.

Dravet syndrome is a severe epileptic encephalopathy starting in the first year of life. Mutations in SCN1A can be identified in the majority of patients, and epileptic seizures in the setting of fever are a clinical hallmark. Fever is also commonly seen after vaccinations and provocation of epileptic seizures by vaccinations in patients with Dravet syndrome has been reported, but not systematically assessed. In a retrospective evaluation of 70 patients with Dravet syndrome and SCN1A mutations, seizures following vaccinations were reported in 27%. In 58% of these patients vaccination-related seizures represented the first clinical manifestation. The majority of seizures occurred after DPT vaccinations and within 72 h after vaccination. Two-thirds of events occurred in the context of fever. Our findings highlight seizures after vaccinations as a common feature in Dravet syndrome and emphasize the need for preventive measures for seizures triggered by vaccination or fever in these children.

Effectiveness of antiepileptic therapy in patients with PCDH19 mutations.

PURPOSE: PCDH19 mutations cause epilepsy and mental retardation limited to females (EFMR) or Dravet-like syndromes. Especially in the first years of life, epilepsy is known to be highly pharmacoresistant. The aim of our study was to evaluate the effectiveness of antiepileptic therapy in patients with PCDH19 mutations. METHODS: We report a retrospective multicenter study of antiepileptic therapy in 58 female patients with PCDH19 mutations and epilepsy aged 2-27 years (mean age 10.6 years). RESULTS: The most effective drugs after 3 months were clobazam and bromide, with a responder rate of 68% and 67%, respectively, where response was defined as seizure reduction of at least 50%. Defining long-term response as the proportion of responders after 12 months of treatment with a given drug in relation to the number of patients treated for at least 3 months, the most effective drugs after 12 months were again bromide and clobazam, with a long-term response of 50% and 43%, respectively. Seventy-four percent of the patients became seizure-free for at least 3 months, 47% for at least one year. SIGNIFICANCE: The most effective drugs in patients with PCDH19 mutations were bromide and clobazam. Although epilepsy in PCDH19 mutations is often pharmacoresistant, three quarters of the patients became seizure-free for at least for 3 months and half of them for at least one year. However, assessing the effectiveness of the drugs is difficult because a possible age-dependent spontaneous seizure remission must be considered.