Loss of Neuron Navigator 2 Impairs Brain and Cerebellar Development.

Cerebellar hypoplasia and dysplasia encompass a group of clinically and genetically heterogeneous disorders frequently associated with neurodevelopmental impairment. The Neuron Navigator 2 (NAV2) gene (MIM: 607,026) encodes a member of the Neuron Navigator protein family, widely expressed within the central nervous system (CNS), and particularly abundant in the developing cerebellum. Evidence across different species supports a pivotal function of NAV2 in cytoskeletal dynamics and neurite outgrowth. Specifically, deficiency of Nav2 in mice leads to cerebellar hypoplasia with abnormal foliation due to impaired axonal outgrowth. However, little is known about the involvement of the NAV2 gene in human disease phenotypes. In this study, we identified a female affected with neurodevelopmental impairment and a complex brain and cardiac malformations in which clinical exome sequencing led to the identification of NAV2 biallelic truncating variants. Through protein expression analysis and cell migration assay in patient-derived fibroblasts, we provide evidence linking NAV2 deficiency to cellular migration deficits. In model organisms, the overall CNS histopathology of the Nav2 hypomorphic mouse revealed developmental anomalies including cerebellar hypoplasia and dysplasia, corpus callosum hypo-dysgenesis, and agenesis of the olfactory bulbs. Lastly, we show that the NAV2 ortholog in Drosophila, sickie (sick) is widely expressed in the fly brain, and sick mutants are mostly lethal with surviving escapers showing neurobehavioral phenotypes. In summary, our results unveil a novel human neurodevelopmental disorder due to genetic loss of NAV2, highlighting a critical conserved role of the NAV2 gene in brain and cerebellar development across species.

Occurrence of hyperventilation-induced high amplitude rhythmic slowing with altered awareness after successful treatment of typical absence seizures and a network hypothesis.

BACKGROUND: Typical absence seizures (AS) are epileptic phenomena typically appearing in children 4-15 years of age and can be elicited by hyperventilation (HV). Hyperventilation-induced high-amplitude rhythmic slowing (HIHARS) represents a paraphysiological response during HV and may manifest with alteration of awareness (HIHARSAA). To date, HIHARSAA has mostly been described in patients without epilepsy. AIM: To describe five patients with treatment-responsive typical AS who, after becoming seizure free, presented with HIHARSAA. METHODS: By using video-electroencephalographic recording (Video-EEG), we describe differential clinical characteristics and ictal electrophysiological patterns of both typical AS and HIHARSAA. RESULTS: We demonstrate that when HIHARSAA occurs in patients with typical AS there is a temporal window between the two phenomena. This suggests that the presence of typical AS precludes the appearance of HIHARSAA. CONCLUSIONS: We hypothesize that alkalosis and dysfunction of the same neural network are involved in both typical AS and HIHARSAA and that their distinct electroclinic manifestations are due to the involvement of different ion channels. SIGNIFICANCE: A better understanding of the characteristics of typical AS and HIHARSAA and of the role of alkalosis in both, can help avoiding misdiagnosis and identifying more suitable therapies for typical AS.

Impact of secukinumab on patient-reported outcomes in moderate to severe plaque psoriasis: a review of clinical studies.

Introduction: Perception of illness varies among individuals and psoriasis of the same severity can be perceived in different ways by patients, making it essential to evaluate quality of life (QoL) since it can provide information on the impact of the disease on the patient's overall well-being. The use of patient-reported outcomes in clinical trials provides the ability to integrate objective clinical assessment with the patient's perception of their own state of health. Areas covered: The introduction of anti-IL17 agents in clinical practice has given patients the possibility to achieve a PASI90 response (almost clear skin) or even higher (complete clear skin) in the majority of patients. There is accumulating evidence in support of PASI90 response as the new standard goal for therapy based on its greater correlation with health-related QoL. The present review summarizes current knowledge of the effects of secukinumab on the QoL of patients with psoriasis using patient-reported outcome measures. Expert Opinion: Secukinumab, the first approved drug of this new class, has fully reached a new therapeutic paradigm not only in terms of clinical efficacy, but also in terms of patient satisfaction and self-rated health.

Genotype/Phenotype Correlations in Tuberous Sclerosis Complex.

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the development of widespread hamartomatous lesions in various organs, including brain, skin, kidneys, heart, and eyes. Central nervous system is almost invariably involved, with up to 85% of patients presenting with epilepsy, and at least half of patients having intellectual disability or other neuropsychiatric disorders including autism spectrum disorder. TSC is caused by the mutation in one of the 2 genes TSC1, at 9q34, and TSC2, at 16p13.3. They respectively encode for hamartin and tuberin, which form an intracellular complex inhibiting the mammalian target of rapamycin. Mammalian target of rapamycin overactivation following the genetic defect determines the cell growth and proliferation responsible for TSC-related lesions, as well as the alterations in neuronal excitability and synaptogenesis leading to epilepsy and neuropsychiatric disorders. A causative mutation for the disorder is identified in about 85% of patients with a clinical diagnosis of TSC. Mosaicism and technology limits likely explain most of the no mutation identified cases. This review confirms that patients with TSC2 mutations considered as a group usually present a more severe phenotype, characterized by higher number of tubers, earlier age at seizure onset and higher prevalence of intellectual disability. However, the clinical phenotype of the disease presents a high variability, thus making the prediction of the phenotype on an individual basis still challenging. The increasing application of new molecular techniques to subjects with TSC has the potential to significantly reduce the rate of patients with no mutation demonstrated and to identify an increasing higher number of mutations. This would hopefully allow a better characterization of higher risk mutations, which might help clinicians to plan individualized surveillance plans. Furthermore, the increasing availability of disease registries to collect clinical and genetics data of patients help to define more valid and clinically oriented genotype or phenotype correlations.

Focal epilepsy with ictal abdominal pain: a case report.

Focal epilepsy with ictal abdominal pain is an unusual partial epilepsy characterized by paroxysmal episodes of abdominal or visceral pain, disturbance of awareness and electroencephalographic abnormalities. We describe a new case of ictal abdominal pain in which gastrointestinal complaints were the only manifestation of seizures and review the previously described pediatric patients. In our patient clinical findings, ictal EEG abnormalities, and a good response to antiepileptic drugs allowed us to make a diagnosis of focal epilepsy with ictal abdominal pain. This is a rare epileptic phenomenon that should be suspected in patients with unexplained paroxysmal abdominal pain and migraine-like symptoms. We suggest that, after the exclusion of more common etiologies, focal epilepsy with ictal abdominal pain should be considered in patients with paroxysmal abdominal pain and ictal EEG abnormalities.

Pancreatic neuroendocrine tumor in a child with a tuberous sclerosis complex 2 (TSC2) mutation.

OBJECTIVE: Pancreatic neuroendocrine tumors (PanNETs) are rare in children with tuberous sclerosis complex (TSC). The objective of this report is to describe a case of PanNET in a boy with TSC. METHODS: We describe the patient's clinical presentation, biochemical workup, and laboratory tests. RESULTS: A 10-year-old boy with a TSC2 mutation presented with a nonsecretory PanNET discovered during routine annual abdominal ultrasound. Surgical distal pancreatectomy with spleen preservation was undertaken. The excised tumor appeared nodular, whitish, and encapsulated. The tumor was composed of pancreatic endocrine monomorphic cells, and the solid appearance of the tumor was interrupted by areas of cystic degeneration. Mitoses were rare; the proliferation index was estimated around 4%. Local lymph nodes showed hyperplasia but were free of metastatic disease. Immunohistochemical examinations were positive for the neuroendocrine markers chromogranin, neurospecific enolase, synaptophysin, CAM52, and vimentin and were negative for CD10 and alpha-1 antitrypsin. The immunohistochemistry also showed a lack of hyperactivation of mammalian target of rapamycin (mTOR) mTOR pathway. All data supported the diagnosis of a grade II well-differentiated neuroendocrine neoplasm, according to the World Health Organization (WHO). CONCLUSIONS: Thirteen non-secretory PanNET cases associated with TSC have been reported, including our patient (9 men and 4 women; 7 with TSC2 mutation). These tumors are usually asymptomatic and can be associated with metastasis; therefore, early diagnosis is crucial for prompt treatment. It is still unclear whether PanNETs should be considered a feature of TSC; however due to this association, we suggest that pancreas investigation should be included in routine examinations in men with TSC2 mutation.

Seizures induced by desloratadine, a second-generation antihistamine: clinical observations.

Some clinical experiences indicate that H1-antihistamines, especially first-generation H1-antagonists, occasionally provoke convulsions in healthy children as well as epileptic patients. Desloratadine is a frequently used second-generation antihistamine considered to be effective and safe for the treatment of allergic diseases. We describe four children who experienced epilepsy associated with the nonsedating H(1)-antagonist desloratadine and discuss the neurophysiologic role of the central histaminergic system in seizure susceptibility. In conclusion, we recommend caution in treating epileptic patients with the histamine H(1)-antagonists, including second- and third-generation drugs that are frequently referred because they are considered to be nonsedating antihistamines.