Contribution to the genetics of symptomatic generalized tonic-clonic seizures: waking and sleep EEGs in siblings

Adolescent-onset epilepsy and deterioration associated with CAD deficiency: A case report

INTRODUCTION

CAD (MIM*114010) encodes a large multifunctional protein with the enzymatic activity of the first three enzymes initiating and controlling the de novo pyrimidine biosynthesis pathway. Biallelic pathogenic variants in CAD cause the autosomal recessive developmental and epileptic encephalopathy 50 (MIM #616457) or CAD deficiency presenting with epilepsy, status epilepticus (SE), neurological deterioration and anemia with anisopoikilocytosis. Mortality is around 9% of patients, mainly related to the no use of its specific treatment with uridine. Majority of reported cases have an early onset during infancy, with some few starting later in childhood.

CASE REPORT

Here we report a deceased female patient with CAD deficiency whose epilepsy started at 14 years. She showed a rapid neurologic deterioration including cognitive decline, electroencephalographic background slowing which later evolved to a fatal refractory SE and supra and infratentorial atrophy on neuroimaging. Anemia developed after SE onset.

METHODS AND RESULTS

her post-mortem whole exome sequencing identified biallelic missense variants in CAD (NM_004341.5): c.[2944G > A];[5366G > A] p.[(Asp982Asn)];[(Arg1789Gln)]. Our review of twenty-eight reported cases (2015-2023) revealed an epilepsy age onset from neonatal period to 7 years and the SE prevalence of 46 %.

DISCUSSION

With our case, we highlight the relevance of suspecting this treatable condition in older patients and in SE with no evident etiology.

Epilepsy and seizure occurrence in a population-based sample of Virginian twins and their families

Epilepsy and seizure occurrence was assessed in a large, population-based sample of Virginian twins and their families. Medical history information on twins and their relatives was collected by questionnaire and used to estimate prevalence of seizures and epilepsy for this sample. Health history information was available on 16,634 twins and their families. Lifetime prevalence of a history of seizures ranged from < 1 to 5%. Concordance rates were larger in monozygotic (MZ) than dizygotic (DZ) pairs overall, however, significant differences between the zygosities were only noted for Caucasian twins. To facilitate interpretation of results, the sample was partitioned into two age groups: 16-35 years and > 35 years of age. In the first age category of twins, significant differences were observed for the following seizure types; epilepsy (0.30 and 0.13, p <0.03), febrile seizures (0.39 and 0.12, p <0.001), and other convulsions/seizures (0.28 and 0.01, p < 0.001). While for twins in the second age category, only the comparison for febrile seizures (0.42 and 0.14, p < 0.001) resulted in a significant difference between zygosities. A family history of seizures was reported in 215 (35.1%) of the 613 seizure positive probands. Increased risk of seizures (1.88-4.64) among relatives of affected versus unaffected individuals was also observed.