Behavioral Phenotype, Electroclinical Features, and Treatment Options in Twins with Lrp2 Candidate Variants (Donnay-Barrow/Foar Syndrome).

The LRP2 gene encodes megalin (LRP-2/GP330), a large single-spanning transmembrane glycoprotein that serves as a multiligand endocytotic receptor and mediates the reabsorption of albumin in the proximal renal tubule. LRP2 is implicated in an autosomal recessive disorder characterized by dimorphisms, ocular anomalies, sensorineural deafness, proteinuria, epilepsy, and intellectual disability: a clinical condition called Donnai-Barrow syndrome (DBS) or facio-oculo-acoustico-renal (FOAR) syndrome. Pathogenic variants in LRP2 have been reported in fewer than 60 patients, but a detailed description of seizures, electroencephalographic patterns, imaging findings, behavioral phenotype, and long-term follow-up is still needed. We provide a clinical report of two mono-chorionic twins with LRP2-related disease manifesting developmental delay, autistic features, seizures, proteinuria, and sleep disorders. By sequencing clinical exome, LRP2 candidate rare variants, c.6815G > A, p. (Arg2272His), inherited from the mother and c.12725A > G, p. (Asp4242Gly), inherited from the father, were identified. During follow-up, at the age of 7, the main clinical features of the patients included insomnia, autistic features, severe psychomotor delay, and absent speech. The patients were under treatment with risperidone, antiseizure medications (ASMs), and supplementation of alpha-lactalbumin for self-injury and sleep disturbance. Our study confirmed the wide spectrum of behavioral and neurological and psychiatric features of this rare condition, suggesting new treatment options.

Electroclinical features of MEF2C haploinsufficiency-related epilepsy: A multicenter European study.

PURPOSE: Epilepsy is a main manifestation in the autosomal dominant mental retardation syndrome caused by heterozygous variants in MEF2C. We aimed to delineate the electro-clinical features and refine the genotype-phenotype correlations in patients with MEF2C haploinsufficiency. METHODS: We thoroughly investigated 25 patients with genetically confirmed MEF2C-syndrome across 12 different European Genetics and Epilepsy Centers, focusing on the epileptic phenotype. Clinical features (seizure types, onset, evolution, and response to therapy), EEG recordings during waking/sleep, and neuroimaging findings were analyzed. We also performed a detailed literature review using the terms "MEF2C", "seizures", and "epilepsy". RESULTS: Epilepsy was diagnosed in 19 out of 25 (~80%) subjects, with age at onset <30 months. Ten individuals (40%) presented with febrile seizures and myoclonic seizures occurred in ~50% of patients. Epileptiform abnormalities were observed in 20/25 patients (80%) and hypoplasia/partial agenesis of the corpus callosum was detected in 12/25 patients (~50%). Nine patients harbored a 5q14.3 deletion encompassing MEF2C and at least one other gene. In 7 out of 10 patients with myoclonic seizures, MIR9-2 and LINC00461 were also deleted, whereas ADGRV1 was involved in 3/4 patients with spasms. CONCLUSION: The epileptic phenotype of MEF2C-syndrome is variable. Febrile and myoclonic seizures are the most frequent, usually associated with a slowing of the background activity and irregular diffuse discharges of frontally dominant, symmetric or asymmetric, slow theta waves with interposed spike-and-waves complexes. The haploinsufficiency of ADGRV1, MIR9-2, and LINC00461 likely contributes to myoclonic seizures and spasms in patients with MEF2C syndrome.

Ictal signs in tuberous sclerosis complex: Clinical and video-EEG features in a large series of recorded seizures.

Epilepsy is the most common neurological symptom in tuberous sclerosis complex (TSC), occurring in 72-85% of affected individuals. Despite the large number of patients reported, their electroclinical phenotype has been rarely described. We analyzed seizure semiology through ictal video-electroencephalography (V-EEG) recordings in a large series of patients. In this multicenter study, we reviewed V-EEGs of 51 patients: ictal recordings were analyzed in correlation with their clinical variables. The median age of epilepsy onset was six months (one day-16 years), with onset in the first year of life in 71% patients (36/51), in 10 of them during the neonatal period. Sixty-five percent of patients (33/51) experienced epileptic spasms in their life, with late-onset (>two years) in five; 42% of the epileptic spasms persisted after age two years, despite the onset in the first year of life. We identified four different electroclinical subsets: focal epilepsy (35%, 18/51), Lennox-Gastaut Syndrome evolution (27%, 14/51), focal seizures with persisting spasms (33%, 17/51), and spasms only (4%, 2/51). We reviewed 45 focal seizures, 13 clusters of epileptic spasms, and seven generalized seizures. In 12 patients, we recorded different seizure types. In 71% of the focal seizures (32/45), the ictal pattern was focal without diffusion. In 38% of the patients (5/13) epileptic spasms were related to typical diffuse slow wave pattern associated with superimposed fast activity, with focal predominance. Focal seizures and focal spasms resulted as the most frequent seizure types in TSC. Seizure onset was variable but showing a predominant involvement of the frontocentral regions (40%). Discrete clinical signs characterized the seizures, and behavioral arrest was the predominant first clinical objective sign. Epileptic spasms were a typical presentation at all ages, frequently asymmetrical and associated with lateralizing features, especially in older patients.

Dramatic relapse of seizures after everolimus withdrawal.

Tuberous sclerosis complex (TSC) is an autosomal dominant multisystemic disorder caused by deregulation of the mTOR pathway, and represents one of the leading genetic causes of epilepsy. mTOR inhibitors (Sirolimus and Everolimus) are currently approved only for the treatment of growing subependymal giant cell astrocytomas, renal angiomyolipomas and lymphangioleiomyomatosis in TSC. However, preclinical and clinical evidence supports their potential role in effectively treating TSC-associated epilepsy, but no consensus on its use in seizures has been reached yet and there are few data on epilepsy outcome after the suspension of mTOR inhibitors treatment. We report for the first time on a patient in whom discontinuation of Everolimus (prescribed for growing subependymal giant cell astrocytomas) was associated with a relapse of seizures twice, and control of seizures was regained after reintroducing the medicine. This clinical report supports the promising potential of Everolimus in treating epilepsy in TSC, and specifically underlines the non-permanent effect on seizures after withdrawal.