Irene Toldo

Pleiotropic effects of spastin on neurite growth depending on expression levels

Hereditary spastic paraplegia (HSP) is characterized by weakness and spasticity of the lower limbs, owing to degeneration of corticospinal axons. The most common form is due to heterozygous mutations in the SPG4 gene, encoding spastin, a microtubule (MT)‐severing protein. Here, we show that neurite growth in immortalized and primary neurons responds in pleiotropic ways to changes in spastin levels. Spastin depletion alters the development of primary hippocampal neurons leading to abnormal neuron morphology, dystrophic neurites, and axonal growth defects. By live imaging with End‐Binding Protein 3‐Fluorescent Green Protein (EB3‐GFP), a MT plus‐end tracking protein, we ascertained that the assembly rate of MTs is reduced when spastin is down‐regulated. Spastin over‐expression at high levels strongly suppresses neurite maintenance, while slight spastin up‐regulation using an endogenous promoter enhances neurite branching and elongation. Spastin severing activity is exerted preferentially on stable acetylated and detyrosinated MTs. We further show that SPG4 nonsense or splice site mutations found in hereditary spastic paraplegia patients result in reduced spastin levels, supporting haploinsufficiency as the molecular cause of the disease. Our study reveals that SPG4 is a dosage‐sensitive gene, and broadens the understanding of the role of spastin in neurite growth and MT dynamics.

The Pitt-Hopkins syndrome: report of 16 new patients and clinical diagnostic criteria.

Pitt‐Hopkins syndrome (PTHS) is characterized by severe intellectual disability, typical facial gestalt and additional features, such as breathing anomalies. Following the discovery of the causative haploinsufficiency of transcription factor 4 (TCF4), about 60 patients have been reported. We looked for TCF4 mutations in 63 patients with a suspected PTHS. Haploinsufficiency of TCF4 was identified in 14 patients, as a consequence of large 18q21.2 chromosome deletions involving TCF4 (2 patients), gene mutations (11 patients) and a t(14q;18q) balanced translocation disrupting TCF4 (one patient). By evaluating the clinical features of these patients, along with literature data, we noticed that, in addition to the typical facial gestalt, the PTHS phenotype results from the various combinations of the following characteristics: intellectual disability with severe speech impairment, normal growth parameters at birth, postnatal microcephaly, breathing anomalies, motor incoordination, ocular anomalies, constipation, seizures, typical behavior and subtle brain abnormalities. Although PTHS is currently considered to be involved in differential diagnosis with Angelman and Rett syndromes, we found that combining the facial characteristics with a detailed analysis of both the physical and the neurological phenotype, made molecular testing for PTHS the first choice. Based on striking clinical criteria, a diagnosis of PTHS was made clinically in two patients who had normal TCF4. This report deals with the first series of PTHS patients of Italian origin.

A novel deletion in the GJA12 gene causes Pelizaeus–Merzbacher-like disease

Pelizaeus–Merzbacher disease (PMD) and Pelizaeus–Merzbacher-like disease (PMLD) are hypomyelinating disorders of the central nervous system with a very similar phenotype. PMD is an X-linked disorder caused by mutations in PLP1. PMLD is an autosomal recessive condition caused by mutations in GJA12. We report a 5-year-old girl with a complex neurological syndrome and severe hypomyelination on brain magnetic resonance imaging. She harbored a homozygous 34-bp deletion in the coding region of GJA12. There are no distinctive features for the differential diagnosis of PMD/PMLD. GJA12 should be analyzed in all patients without PLP1 mutations but should also be considered the initial genetic test in women and in patients with consanguineous parents.

Efficacy and safety of topiramate in refractory epilepsy of childhood : Long-term follow-up study

This study aimed to evaluate the long-term efficacy and safety of topiramate in treating children with drug-resistant epilepsy. A multicentric, retrospective, open-label, add-on study was undertaken of 277 children (mean age 8.4 years; range 12 months to 16 years) affected by drug-resistant epilepsy. The efficacy was rated according to the seizure types and epilepsy syndrome. After a mean period of 27.5 months of treatment (range 24—61 months), 11 patients (4%) were seizure free and 56 (20%) had more than 50% reduction in seizure frequency. The efficacy of topiramate treatment was noted in localization-related epilepsy and in generalized epilepsy. In addition, in a group of 114 patients, we compared the initial efficacy (evaluated after a mean of 9 months of follow-up) and the retention at a mean of 30 months of topiramate with regard to loss of efficacy (defined as the return to the baseline seizure frequency). Fifty-five (48%) of 114 patients were initial responders. The retention at a mean of 30 months was 23 of 114 patients (20%), 4 of whom (3.5%) were still seizure free. A loss of efficacy occurred in 32 of the 55 initial responders (58%). It was prominent in patients with generalized epilepsy, such as symptomatic infantile spasms and Lennox-Gastaut syndrome, as well as in those with Dravet syndrome. By contrast, a well-sustained topiramate efficacy was noted among patients with localization-related epilepsy. Globally, adverse events were observed in 161 patients (58%) and were mainly represented by weight loss, hyperthermia, sedation, and nervousness, which, in most cases, disappeared after slowing titration or reducing the dosage of the drug. In conclusion, the present long-term study confirms that topiramate represents a useful drug effective in a wide range of seizures and epilepsy syndromes. Moreover, preliminary data seem to suggest that the efficacy of topiramate, when evaluated in the long-term perspective, is more sustained in localization-related epilepsy than in generalized epilepsy. (J Child Neurol 2005;20:893—897).

Longitudinal Electroencephalographic (EEG) Findings in Pediatric Anti-N-Methyl-d-Aspartate (Anti-NMDA) Receptor Encephalitis The Padua Experience

To contribute to characterize electroencephalographic (EEG) activity in pediatric anti-N-methyl-d-aspartate (anti-NMDA) receptor encephalitis, we reviewed electroclinical data of 5 children with anti-NMDA receptor encephalitis diagnosed in our department. We identified 4 longitudinal electroencephalographic phases: in the early phase, background activity was normal, with intermixed nonreactive slow waves; in the florid phase, background activity deteriorated with appearance of sequences of peculiar rhythmic theta and/or delta activity unrelated to clinical changes, unresponsive to stimuli and antiepileptic medications; in the recovery phase, these sequences decreased and reactive posterior rhythm re-emerged; electroencephalogram normalized 2 to 5 months after onset. In conclusion, in the presence of evocative clinical history, recognizing a characteristic longitudinal electroencephalographic activity could provide ancillary aspects addressing the diagnosis and the overall management of children with anti-N-methyl-d-aspartate receptor encephalitis; in particular, knowing that peculiar and recurrent paroxysmal nonepileptic rhythmic theta-delta patterns can occur in these patients could help distinguish paroxysmal epileptic and nonepileptic electroencephalographic activity.

Vertebral and spinal cavernous angiomas associated with familial cerebral cavernous malformation.

BACKGROUND Cerebral cavernous malformations are vascular malformations that affect the CNS and have been associated with cutaneous, retinal, and hepatic lesions. Until now, vertebral hemangiomas associated with CCM have been described only in one case. The coexistence of intracranial and spinal cavernous angiomas in familial CCM is extremely rare. In addition to previous studies, the occurrence of spinal, vertebral, and cutaneous cavernous angiomas is now described in different members of a large family with CCM. CASE DESCRIPTION Our study reports a previously described family (IFCAS-07) with 12 members affected by autosomal dominant cavernous angiomas: 11 had CCM either alone or associated with hepatic or retinal angiomas, and one had only hepatic angioma. In all 11 members affected by CCM, the mutation of CCM1 gene was detected. During the follow-up, 8 subjects underwent a spinal MRI: 2 because they were symptomatic (thoracic paresthesias, enuresis, back pain) and 6 as a screening examination. Spinal MRI showed in 5 subjects spinal cavernous angiomas either alone or associated with vertebral hemangiomas. CONCLUSIONS To our knowledge, this is the largest family reported with different subjects affected by CCM associated with multiple cavernous angiomas throughout (brain and spinal cord) and besides (retina, skin, liver, and vertebral column) the CNS. Comprehensive care of patients with familial CCM includes screening of all the tissues that can be affected and appropriate management by specialists. We emphasize the importance of spinal MRI in the diagnosis of spinal and vertebral cavernous angiomas in all patients affected by familial CCM.

Intrathecal synthesis of oligoclonal bands in rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation syndrome: new evidence supporting immunological pathogenesis.

Rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation syndrome (ROHHADS) is a rare, but potentially lethal, pediatric disorder. To date, nearly 80 patients have been reported in the literature; however, the etiopathogenesis is still unclear and debated. Both genetic and paraneoplastic or immune-mediated causes have been supposed to be involved in this syndrome. Nonetheless, at this time, a diagnostic biomarker is not available and diagnosis is based exclusively on clinical criteria. Aiming to establish the immune-mediated pathogenesis, we report 2 children with a clinical picture consistent with ROHHADS and whose cerebrospinal fluid analysis disclosed an intrathecal synthesis of oligoclonal bands. Even if many aspects remain to be explained, this finding suggests that ROHHADS could share similar pathogenetic mechanisms with other immune-mediated central nervous system disorders, and even more important, it might pave the way to a therapeutic chance for these patients by means of immunotherapy.

Osmophobia as an early marker of migraine: a follow-up study in juvenile patients.

Background: Osmophobia is frequent in children with migraine (20–35%) but can also occur in up to 14% of cases with tension-type headache (TTH). So far, the prognostic role of this symptom in children with primary headaches has never been evaluated. Methods: A longitudinal prospective study was conducted on 90 young patients with TTH (37 with osmophobia, 53 without osmophobia). We evaluated whether osmophobia could predict the diagnosis transformation from TTH to migraine after a 3-year follow-up. Results and Discussion: In our cases the rate of diagnosis change was significantly greater in cases with osmophobia (62%) than in those without (23%). Osmophobia persisted at a 3-year follow-up in the majority of our cases (85%) and it was found to be one of the major predictors for the development of migraine; other predictors of evolution to migraine were phonophobia, a probable rather than certain diagnosis of TTH and olfactory triggers (p < 0.05). Conclusion: Our data confirm that osmophobia has an important diagnostic and prognostic role in children with primary headaches and should be systematically investigated at diagnosis and during follow-up.

Multimodal neuroimaging in a child with sporadic hemiplegic migraine: A contribution to understanding pathogenesis

Background: Hemiplegic migraine (HM) is a rare variety of migraine with aura, characterized by motor deficits during the aura, often beginning in childhood. The hemiplegic attacks can be severe and prolonged but the prognosis is usually good. Data on neuroimaging, including diffusion-weighted imaging (DWI) and spectroscopy, during prolonged attacks of HM are quite limited, particularly in children. Case: An eight-year-old female had a prolonged attack of sporadic HM characterized by right-sided hemiplegia, global aphasia, fever and impairment of consciousness. MRI nine hours after hemiplegia onset was negative, while the following MRI scans (days 4 and 11) documented a progressive increase in cortical swelling in the left hemisphere with mild hyperintensity on DWI and mild reduction of apparent diffusion coefficient values. Proton MRI spectroscopy (MRS) (day 15) showed a decrease in the N-acetylaspartate/creatine ratio in the left hemisphere. 99mTc-ECD single-photon emission tomography (SPET) (day 27) showed marked left hemispheric hypoperfusion. The patient recovered completely after 40 days and neuroimaging follow-up (MRI and SPET) after six months was normal. The patient carried a missense mutation of the ATP1A2 gene. Conclusion: Multimodal neuroimaging (MRI, DWI, MRS, SPET) in a prolonged HM attack supports evidence for a primary neuronal dysfunction.

Nonorganic (psychogenic) visual loss in children: a retrospective series.

Background: Few studies provide follow-up information or systematic investigation of prognostic parameters of nonorganic (psychogenic) visual loss in children. Methods: A retrospective case series analysis was performed on 58 patients younger than 16 years old who had nonorganic visual loss and underwent at least a 3-month follow-up clinic visit and/or telephone interview between 1992 and 2007 at a single institution in Italy. All patients underwent a full neurologic, ophthalmologic, and orthoptic evaluation. Visual electrophysiologic tests were performed in many patients as part of the evaluation. Neuroimaging was performed and psychiatric referral was made only as needed. We collected data on the age at onset, time to diagnosis of nonorganic visual loss, type and duration of visual symptoms, and concomitant psychologic or psychosocial difficulties. Results: Visual deficits consisted mostly of reduced visual acuity (76%) and visual field defects (48%). The diagnosis of nonorganic visual loss could be reached with confidence by means of observing inconsistent performance on a wide array of visual function tests, and, in doubtful cases, by means of electrophysiologic investigations. The mean time from onset to diagnosis was 3.1 months. The mean duration of visual symptoms from reported onset to disappearance was 7.4 months. Complete resolution of all visual symptoms occurred in 93% of patients and did so within 12 months of diagnosis in 85% of patients. There was no correlation between the duration of visual symptoms and age at onset, sex, time to diagnosis, type of ocular symptoms, or presence of psychosocial or psychologic difficulties. Conclusions: Our study extends the follow-up information and confirms the findings of previous investigators in showing that nonorganic visual loss in children generally resolves spontaneously within 1 year and that no major psychiatric disorders are present or will appear after diagnosis. However, psychosocial stressors are often present and may predispose to this manifestation. There are no obvious predictors of rate of recovery.