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Bilateral frontoparietal polymicrogyria, Lennox-Gastaut syndrome, and GPR56 gene mutations.

ABSTRACT: PURPOSE:Bilateral frontoparietal polymicrogyria (BFPP) has been reported in sporadic patients and in recessive pedigrees. Eleven mutations in GPR56, a gene encoding an evolutionarily dynamic G-protein-coupled receptor, have been identified in 29 patients from 18 families. The clinical features of BFPP include severe mental retardation, motor and language impairment, and epilepsy. No detailed description of the epilepsy is available for the patients reported to date. We report three consanguineous families in which four affected individuals with BFPP and GPR56 mutations had Lennox-Gastaut syndrome. METHODS:Family studies, brain magnetic resonance imaging (MRI), electroencephalography (EEG)-video recordings, and mutation analysis. RESULTS:In Family 1, with one affected proband, we found an R565W change in the second extracellular loop of GPR56, involving a highly conserved aminoacidic residue. In Family 2, with one affected proband, we found an R79X change affecting the protein N-terminus and predicted to cause a premature truncation with loss of the G-protein-coupled receptor proteolytic site. In family 3, with two affected siblings, we found an R33P substitution in the protein N-terminus, involving a highly conserved aminoacidic residue. Epilepsy, present in all four patients, had started between ages 1 and 8 years, with infantile spasms in one patient and with de novo Lennox-Gastaut syndrome in the remaining three. All patients had Lennox-Gastaut syndrome when last observed, at ages 13 to 32 years. DISCUSSION:Several genes, when mutated, can cause malformations of cortical development that have been associated with the Lennox-Gastaut syndrome. BFPP caused by GPR56 mutations represents an additional, although rare, genetically determined cause of Lennox-Gastaut syndrome.

SUBMITTER: Parrini E

PROVIDER: S-EPMC4271835 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature

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Bilateral frontoparietal polymicrogyria, Lennox-Gastaut syndrome, and GPR56 gene mutations.

Parrini Elena E Ferrari Anna Rita AR Dorn Thomas T Walsh Christopher A CA Guerrini Renzo R

Epilepsia 20081006 6

<h4>Purpose</h4>Bilateral frontoparietal polymicrogyria (BFPP) has been reported in sporadic patients and in recessive pedigrees. Eleven mutations in GPR56, a gene encoding an evolutionarily dynamic G-protein-coupled receptor, have been identified in 29 patients from 18 families. The clinical features of BFPP include severe mental retardation, motor and language impairment, and epilepsy. No detailed description of the epilepsy is available for the patients reported to date. We report three consa ...[more]

PMID: 19016831

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Project description:Bilateral frontoparietal polymicrogyria (BFPP, MIM 606854) is a heterogeneous autosomal recessive disorder of abnormal cortical lamination, leading to moderate-to-severe intellectual disability (ID), seizure disorder, and motor difficulties, and caused by mutations in the G protein-coupled receptor 56 ( GPR56 ) gene. Twenty-eight mutations in 40 different families have been reported in the literature. The clinical and neuroimaging phenotype is consistent in these cases. The BFPP cortex consists of numerous small gyral cells, with scalloping of the cortical-white matter junction. There are also associated white matter, brain stem, and cerebellar changes. GPR56 is a member of an adhesion G protein-coupled receptor family with a very long N-terminal stalk and seven transmembrane domains. In this study, we identified three families from Pakistan, ascertained primarily for ID, with overlapping approximately 1 Mb region (chr16:56,973,335-57,942,866) of homozygosity by descent, including 24 RefSeq genes. We found three GPR56 homozygous mutations, using next-generation sequencing. These mutations include a substitutional variant, c.1460T?>?C; p.L487P, (chr16:57693480 T?>?C), a 13-bp insertion causing the frameshift and truncating mutation, p.Leu269Hisfs*21 (NM_005682.6:c.803_804insCCATGGAGGTGCT; Chr16: 57689345_57689346insCCATGGAGGTGCT), and a truncating mutation c.1426C?>?T; p.Arg476* (Chr16:57693446C?>?T). These mutations fully segregated with ID in these families and were absent in the Exome Aggregation Consortium database that has approximately 8,000 control samples of South Asian origin. Two of these mutations have been reported in ClinVar database, and the third one has not been reported before. Three families from Pakistan with GPR56 mutations have been reported before. With the addition of our findings, the total number of mutations reported in Pakistani patients now is six. These results increase our knowledge regarding the mutational spectrum of the GPR56 gene causing BFPP/ID.

Project description:ObjectivesThis study aimed to investigate the functional network effects of corpus callosotomy (CC), a well-recognized palliative surgical therapy for patients with Lennox-Gastaut syndrome (LGS). Specifically, we sought to gain insight into the effects of CC on LGS remission, based on brain networks in LGS by calculating network metrics and evaluating by network measures before and after surgery.MethodsElectroencephalographic recordings made during preoperative and 3-month postoperative states in 14 patients with LGS who had undergone successful CC were retrospectively analyzed. First, undirected correlation matrices were constituted for the mathematical expression of functional networks. Then, we plotted these networks to analyze the effects of CC on connectivity. In addition, conventional local and global network measures were applied to evaluate differences in network topology between preoperative and postoperative states.ResultsIn the preoperative state, hubs were mainly distributed around the paramedian regions. After CC, the hubs moved from the paramedian regions to the dual-hemisphere and even the lateral regions. Thus, the general connectivity state became more homogeneous, which was verified by network plots and statistical analysis of local measures. The results of global network measures indicated a decreased clustering coefficient in the delta band, decreased characteristic path length in both the delta and gamma bands, and increased global efficiency in the gamma band.ConclusionOur results showed a consistent variation in the global brain network that converted to a small-world topology with an optimal balance of functional integration and segregation of the network. Such changes were positively correlated with satisfactory surgery results, which could be interpreted as being indicative of LGS recovery process after CC. For patients with refractory LGS along with no focal epileptogenic zone findings, which were not suitable for the resective surgical therapy, our results verified that CC could work as an effective surgical treatment option.

Project description:Lennox-Gastaut syndrome (LGS), a childhood-onset severe developmental and epileptic encephalopathy (DEE), is an entity that encompasses a heterogenous group of aetiologies, with no single genetic cause. It is characterised by multiple seizure types, an abnormal EEG with generalised slow spike and wave discharges and cognitive impairment, associated with high morbidity and profound effects on the quality of life of patients and their families. Drug-refractory seizures are a hallmark and treatment is further complicated by its multiple morbidities, which evolve over the patient's lifetime. This review provides a comprehensive overview of the current and future options for the treatment of seizures associated with LGS. Six treatments are specifically indicated as adjunct therapies for the treatment of seizures associated with LGS in the US: lamotrigine, clobazam, rufinamide, topiramate, felbamate and most recently cannabidiol. These therapies have demonstrated reductions in drop seizures in 15%-68% of patients across trials, with responder rates (≥ 50% reduction in drop seizures) of 37%-78%. Valproate is still the preferred first-line treatment, generally in combination with lamotrigine or clobazam. Other treatments frequently used off-label include the broad spectrum anti-epileptic drugs (AED) levetiracetam, zonisamide and perampanel, while recent evidence from observational studies has indicated that a newer AED, the levetiracetam analogue brivaracetam, may be effective and well tolerated in LGS patients. Other treatments in clinical development include fenfluramine in late phase III, perampanel, soticlestat-OV953/TAK-953, carisbamate and ganaxolone. Non-pharmacologic interventions include the ketogenic diet, vagus nerve stimulation and surgical interventions; these are also expanding, with the potential for less invasive techniques for corpus callosotomy that have promise for reducing complications. However, despite these advancements, patients continue to experience a significant burden. Because LGS is not a single entity, tailoring of treatment is needed as opposed to a 'one size fits all' approach. Further research is needed into the underlying aetiologies and pathophysiology of LGS, together with advancements in treatments that encompass the spectrum of seizures associated with this complex syndrome.

Project description:Lennox-Gastaut syndrome (LGS) is a severe epileptic and developmental encephalopathy that is associated with a high rate of morbidity and mortality. It is characterized by multiple seizure types, abnormal electroencephalographic features, and intellectual disability. Although intellectual disability and associated behavioral problems are characteristic of LGS, they are not necessarily present at its outset and are therefore not part of its diagnostic criteria. LGS is typically treated with a variety of pharmacological and non-pharmacological therapies, often in combination. Management and treatment decisions can be challenging, due to the multiple seizure types and comorbidities associated with the condition. A panel of five epileptologists met to discuss consensus recommendations for LGS management, based on the latest available evidence from literature review and clinical experience. Treatment algorithms were formulated. Current evidence favors the continued use of sodium valproate (VPA) as the first-line treatment for patients with newly diagnosed de novo LGS. If VPA is ineffective alone, evidence supports lamotrigine, or subsequently rufinamide, as adjunctive therapy. If seizure control remains inadequate, the choice of next adjunctive antiepileptic drug (AED) should be discussed with the patient/parent/caregiver/clinical team, as current evidence is limited. Non-pharmacological therapies, including resective surgery, the ketogenic diet, vagus nerve stimulation, and callosotomy, should be considered for use alongside AED therapy from the outset of treatment. For patients with LGS that has evolved from another type of epilepsy who are already being treated with an AED other than VPA, VPA therapy should be considered if not trialed previously. Thereafter, the approach for a de novo patient should be followed. Where possible, no more than two AEDs should be used concomitantly. Patients with established LGS should undergo review by a neurologist specialized in epilepsy on at least an annual basis, including a thorough reassessment of their diagnosis and treatment plan. Clinicians should always be vigilant to the possibility of treatable etiologies and alert to the possibility that a patient's diagnosis may change, since the seizure types and electroencephalographic features that characterize LGS evolve over time. To date, available treatments are unlikely to lead to seizure remission in the majority of patients and therefore the primary focus of treatment should always be optimization of learning, behavioral management, and overall quality of life.

Dataset Information

Bilateral frontoparietal polymicrogyria, Lennox-Gastaut syndrome, and GPR56 gene mutations.

Publications

Bilateral frontoparietal polymicrogyria, Lennox-Gastaut syndrome, and GPR56 gene mutations.

Similar Datasets

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