Gaetano Tortorella

Recurrent Rearrangements in Synaptic and Neurodevelopmental Genes and Shared Biologic Pathways in Schizophrenia, Autism, and Mental Retardation

CONTEXT Results of comparative genomic hybridization studies have suggested that rare copy number variations (CNVs) at numerous loci are involved in the cause of mental retardation, autism spectrum disorders, and schizophrenia. OBJECTIVES To provide an estimate of the collective frequency of a set of recurrent or overlapping CNVs in 3 different groups of cases compared with healthy control subjects and to assess whether each CNV is present in more than 1 clinical category. DESIGN Case-control study. SETTING Academic research. PARTICIPANTS We investigated 28 candidate loci previously identified by comparative genomic hybridization studies for gene dosage alteration in 247 cases with mental retardation, in 260 cases with autism spectrum disorders, in 236 cases with schizophrenia or schizoaffective disorder, and in 236 controls. MAIN OUTCOME MEASURES Collective and individual frequencies of the analyzed CNVs in cases compared with controls. RESULTS Recurrent or overlapping CNVs were found in cases at 39.3% of the selected loci. The collective frequency of CNVs at these loci is significantly increased in cases with autism, in cases with schizophrenia, and in cases with mental retardation compared with controls (P < .001, P = .01, and P = .001, respectively, Fisher exact test). Individual significance (P = .02 without correction for multiple testing) was reached for the association between autism and a 350-kilobase deletion located at 22q11 and spanning the PRODH and DGCR6 genes. CONCLUSIONS Weakly to moderately recurrent CNVs (transmitted or occurring de novo) seem to be causative or contributory factors for these diseases. Most of these CNVs (which contain genes involved in neurotransmission or in synapse formation and maintenance) are present in the 3 pathologic conditions (schizophrenia, autism, and mental retardation), supporting the existence of shared biologic pathways in these neurodevelopmental disorders.

Congenital muscular dystrophies with defective glycosylation of dystroglycan A population study

Background: Congenital muscular dystrophies (CMD) with reduced glycosylation of alpha-dystroglycan (α-DG) are a heterogeneous group of conditions associated with mutations in six genes encoding proven or putative glycosyltransferases. Objectives: The aim of the study was to establish the prevalence of mutations in the six genes in the Italian population and the spectrum of clinical and brain MRI findings. Methods: As part of a multicentric study involving all the tertiary neuromuscular centers in Italy, FKRP, POMT1, POMT2, POMGnT1, fukutin, and LARGE were screened in 81 patients with CMD and α-DG reduction on muscle biopsy (n = 76) or with a phenotype suggestive of α-dystroglycanopathy but in whom a muscle biopsy was not available for α-DG immunostaining (n = 5). Results: Homozygous and compound heterozygous mutations were detected in a total of 43/81 patients (53%), and included seven novel variants. Mutations in POMT1 were the most prevalent in our cohort (21%), followed by POMT2 (11%), POMGnT1 (10%), and FKRP (9%). One patient carried two heterozygous mutations in fukutin and one case harbored a new homozygous variant in LARGE. No clear-cut genotype-phenotype correlation could be observed with each gene, resulting in a wide spectrum of clinical phenotypes. The more severe phenotypes, however, appeared to be consistently associated with mutations predicted to result in a severe disruption of the respective genes. Conclusions: Our data broaden the clinical spectrum associated with mutations in glycosyltransferases and provide data on their prevalence in the Italian population.

Topiramate as add-on drug in severe myoclonic epilepsy in infancy: an Italian multicenter open trial

PURPOSE This study was to evaluate the efficacy and safety of topiramate (TPM) in patients with severe myoclonic epilepsy in infancy (SMEI) and refractory seizures. METHODS We performed a prospective multicentric open label add-on study in 18 patients (age 2-21 years, mean 9 years) with SMEI and refractory seizures of different types. TPM was added to one or two other baseline drugs and the efficacy was rated according to seizure type and frequency. RESULTS TPM was initiated at a daily dose of 0.5-1 mg/kg, followed by a 2-week titration at increments of 1-3 mg/kg/24 h up to a maximum daily dose of 12 mg/kg. After a mean period of 11.9 months (range 2-24 months), three patients (16.7%) had 100% fewer seizures and ten patients (55.5%) had a more than 50% seizure decrease. In no patient there was a seizure worsening. Mild to moderate adverse events were present in four patients (22.2%), represented by weight loss, hypermenorrhoea, renal microlithiasis, nervousness and dysarthric speech. CONCLUSION TPM may be a useful drug in patients with SMEI, being particularly effective against generalized tonic-clonic seizures. Further studies are needed to evaluate the early use of this drug in such a severe syndrome.

Familial periventricular heterotopia Missense and distal truncating mutations of the FLN1 gene

ObjectiveTo examine the clinical and MRI associations in bilateral periventricular nodular heterotopia (BPNH) (MIM # 300049) in two families segregating a missense mutation and a C-terminal deletion of the filamin 1 (FLN1) gene. BackgroundClassical familial BPNH, an X-linked dominant disorder, has been associated with protein truncations or splicing mutations, which tend to cluster at the N-terminal of the FLN1 protein, causing severe predicted loss of the protein function. The clinical syndrome includes symmetrical contiguous nodular heterotopia lining the lateral ventricles, epilepsy, mild retardation to normal cognitive level in affected females, and prenatal lethality in hemizygous boys. MethodsClinical examination, cognitive testing, MRI, mutation analysis (direct sequencing, single-strand conformation polymorphism) in seven patients from two families with BPNH. ResultsIn Family 1, harboring an A > T change in exon 2 (E82V), heterotopic nodules were few, asymmetric, and noncontiguous. Five boys born from affected females had died unexpectedly early in life. In Family 2, harboring an 8 base pair deletion in exon 47 (7627_7634del TGTGCCCC), heterotopic nodules were thick and contiguous. Affected females in both families showed normal to borderline IQ and epilepsy. ConclusionMissense mutations and distal truncations consistent with partial loss of FLN1 function cause familial BPNH with the classical clinical phenotype including epilepsy and mild mental retardation, if any. However, missense mutations have milder anatomic consequences in affected females and are possibly compatible with live birth but short survival of boys.

Bilateral occipital calcification, epilepsy and coeliac disease: clinical and neuroimaging features of a new syndrome.

Twenty patients affected by bilateral occipital cortical-subcortical calcification (BOC) are described, 19 (95%) had epilepsy. In 8 of 16 cases studied, intestinal biopsy revealed coeliac disease. Fourteen patients had occipital partial epilepsy with a relatively benign outcome, while 4 patients were affected by a severe form of epilepsy, with very frequent, drug-resistant, generalised and partial seizures with mental deterioration. One patient had a single episode of convulsive status epilepticus at four months of age. The neurological examination was normal in all patients. CT showed flocculo-nodular, cortico-subcortical BOC, without enhancement and without lobar or hemispheric atrophy. MRI was normal. The clinical and neuroimaging features of these patients are different therefore from those with the Sturge-Weber Syndrome. The study confirms a high prevalence of coliac disease in patients with BOC, but the relationship between these two pathologies still needs to be clarified.

Ictal and interictal EEG abnormalities in ADHD children recorded over night by video-polysomnography

In this paper we explore the prevalence of ictal and interictal epileptiform discharges (IEDs) and sleep disorders in ADHD children referred to a sleep clinic for all night video-PSG. Forty-two ADHD outpatients (35 males and 7 females) underwent video-PSG and a behavioural/neuropsychological assessment. Spearman correlation coefficients (p<0.05 criterion level) were used to assess the association between cognitive, behavioural, clinical (co-morbidity), sleep (sleep efficiency) and EEG (seizures, IEDs, localization of IEDs foci) variables. Sleep disorders were found in 86% of ADHD children; among these, 26% had RLS. 53.1% of ADHD children had IEDs (28.2% centro-temporal spikes, 12.5% frontal spikes, 9.3% temporal-occipital spikes and 2.3% generalized S-W). Nocturnal seizures were recorded in three patients: two with atypical interictal rolandic spikes and one with left frontal slow abnormalities. A significant relationship (p<0.05) emerges between nocturnal seizures and WISC-R IQ score and visual-spatial memory test and between some cognitive variables and interictal rolandic spikes. High levels of inattention, impulsivity/hyperactivity and oppositional behaviours were related (p<0.01 or 0.05) with Restless Leg Syndrome diagnosis. In conclusion, ADHD is a condition often associated with EEG epileptiform abnormalities. Seizures/IEDs presence seems to play a role on cognitive abilities, conversely sleep disorders have a stronger impact on behavioural rather than cognitive indicators.

PRRT2 mutations in familial infantile seizures, paroxysmal dyskinesia, and hemiplegic migraine

ABSTRACT Objective: To perform a clinical and genetic study of a family with benign familial infantile seizures (BFIS) and, upon finding a PRRT2 gene mutation, to study a cohort of probands with a similar phenotype. We extended the study to all available family members to find out whether PRRT2 mutations cosegregated with additional symptoms. Methods: We carried out a clinical and genealogic study of a 3-generation family and of 32 additional probands with BFIS (11 families), infantile convulsions and paroxysmal choreoathetosis (ICCA) (9 families), BFIS/generalized epilepsy with febrile seizures plus (5 families), and sporadic benign neonatal or infantile seizures (7 probands/families). We performed a genetic study consisting of linkage analysis and PRRT2 screening of the 33 probands/families. Results: We obtained a positive linkage in the 16p11.3-q23.1 chromosomal region in the large BFIS family. Mutation analysis of PRRT2 gene revealed a c.649dupC (p.Arg217Profs*8) in all affected individuals. PRRT2 analysis of the 32 additional probands showed mutations in 10, 8 familial and 2 sporadic, probands. Overall we found PRRT2 mutations in 11 probands with a mutation rate of 11 out of 33 (33%). BFIS co-occurred with migraine and febrile seizures in 2 families, with childhood absence epilepsy in one family and with hemiplegic migraine in one family. Conclusion: Our results confirm the predominant role of PRRT2 mutations in BFIS and expand the spectrum of PRRT2-associated phenotypes to include febrile seizures, childhood absence seizures, migraine, and hemiplegic migraine.

Nonsyndromic mental retardation and cryptogenic epilepsy in women with doublecortin gene mutations

DCX mutations cause mental retardation in male subjects with lissencephalypachygyria and in female subjects with subcortical band heterotopia (SBH). We observed four families in which carrier women had normal brain magnetic resonance imaging (MRI) and mild mental retardation, with or without epilepsy. Affected male subjects had SBH or pachygyria‐SBH. In two families, the phenotype was mild in both genders. In the first family, we found a tyr138his mutation that is predicted to result in abnormal folding in the small hinge region. In the second family, we found an arg178cys mutation at the initial portion of R2, in the putative β‐sheet structure. Carrier female subjects with normal MRI showed no somatic mosaicism or altered X‐inactivation in lymphocytes, suggesting a correlation between mild mutations and phenotypes. In the two other families, with severely affected boys, we found arg76ser and arg56gly mutations within the R1 region that are predicted to affect DCX folding, severely modifying its activity. Both carrier mothers showed skewed X‐inactivation, possibly explaining their mild phenotypes. Missense DCX mutations may manifest as non‐syndromic mental retardation with cryptogenic epilepsy in female subjects and SBH in boys. Mutation analysis in mothers of affected children is mandatory, even when brain MRI is normal. Ann Neurol 2003

Levetiracetam during 1-year follow-up in children, adolescents, and young adults with refractory epilepsy.

PURPOSE To evaluate the efficacy and safety of levetiracetam (LEV) in refractory crypto/symptomatic, partial or generalised epilepsy in children, adolescents and young adults. METHODS We performed a prospective open label add-on study in 99 patients (age 12 months to 32 years, mean 14 years) with partial or generalised, crypto/symptomatic seizures. Levetiracetam was added to no more than two baseline AEDs and the efficacy was rated according to seizure type and frequency. RESULTS LEV was initiated at the starting dose of 10mg/kg/day with 5-day increments up to 50 mg/kg/day, unless it was not tolerated. Concomitant therapy was generally not modified throughout the study. After a mean follow-up period of 6.7 months (range 3 weeks to 29 months), 11 patients (11.1%) were free of seizures (cryptogenic partial epilepsy, 5; symptomatic partial epilepsy, 6). A more than 75% seizure decrease was found in 14 patients (14.1%) and >50% in 8 (8.1%). Seizures were unchanged in 38 (38.4%), and worsened in 23 (23.2%). Mild and transient adverse side effects were found in 17 patients (17.2%), mostly represented by irritability and drowsiness. CONCLUSION LEV appears to be well tolerated in children and adolescents with severe epilepsy and seems to be a broad spectrum AED, though in our experience, it was more effective against partial seizures with or without secondarily generalisation. LEV efficacy in other epilepsy syndrome should be evaluated further in homogeneous, more selected patients.

Topiramate as add-on drug in children, adolescents and young adults with Lennox-Gastaut syndrome: An Italian multicentric study

The purpose of the study was to evaluate the efficacy and safety of topiramate (TPM) as adjunctive therapy in children, adolescents and young adults with Lennox-Gastaut syndrome (LGS). We performed a prospective open label add-on study in 45 patients (age 4-34 years, mean 15.9 years) with LGS and refractory seizures. TPM was added to one or two other baseline drugs and the efficacy was rated according to seizure type and frequency. TPM was initiated at the daily dose of 0.5-1 mg/kg, followed by a 2-week titration at increments of 1-3 mg/kg/24 h, up to a maximum daily dose of 12 mg/kg. After a mean period of 15.8 months of treatment (range 3-98 months), at a mean dose of 4.1 mg/kg/24 h (range 1.4-12 mg/kg), 18 patients (40%) had a seizure reduction more than 50%. TPM appeared to be effective mainly in major seizures (drop attacks, tonic and tonic-clonic seizures). Mild to moderate adverse events were present in 24 patients (53.3%), mostly represented by drowsiness, nervousness, hyporexia with or without weight loss and cognitive dulling. In conclusion, TPM adjunctive therapy reduced the number of drop attacks and major motor seizures in 40% of patients with LGS and produced only mild or moderate adverse events.