Bernhard Schmitt

Genotypic and phenotypic spectrum of pyridoxine-dependent epilepsy (ALDH7A1 deficiency)

Pyridoxine-dependent epilepsy was recently shown to be due to mutations in the ALDH7A1 gene, which encodes antiquitin, an enzyme that catalyses the nicotinamide adenine dinucleotide-dependent dehydrogenation of l-α-aminoadipic semialdehyde/l-Δ1-piperideine 6-carboxylate. However, whilst this is a highly treatable disorder, there is general uncertainty about when to consider this diagnosis and how to test for it. This study aimed to evaluate the use of measurement of urine l-α-aminoadipic semialdehyde/creatinine ratio and mutation analysis of ALDH7A1 (antiquitin) in investigation of patients with suspected or clinically proven pyridoxine-dependent epilepsy and to characterize further the phenotypic spectrum of antiquitin deficiency. Urinary l-α-aminoadipic semialdehyde concentration was determined by liquid chromatography tandem mass spectrometry. When this was above the normal range, DNA sequencing of the ALDH7A1 gene was performed. Clinicians were asked to complete questionnaires on clinical, biochemical, magnetic resonance imaging and electroencephalography features of patients. The clinical spectrum of antiquitin deficiency extended from ventriculomegaly detected on foetal ultrasound, through abnormal foetal movements and a multisystem neonatal disorder, to the onset of seizures and autistic features after the first year of life. Our relatively large series suggested that clinical diagnosis of pyridoxine dependent epilepsy can be challenging because: (i) there may be some response to antiepileptic drugs; (ii) in infants with multisystem pathology, the response to pyridoxine may not be instant and obvious; and (iii) structural brain abnormalities may co-exist and be considered sufficient cause of epilepsy, whereas the fits may be a consequence of antiquitin deficiency and are then responsive to pyridoxine. These findings support the use of biochemical and DNA tests for antiquitin deficiency and a clinical trial of pyridoxine in infants and children with epilepsy across a broad range of clinical scenarios.

Pyridoxal 5 '-phosphate may be curative in early-onset epileptic encephalopathy

SummaryNeonatal epileptic encephalopathy can be caused by inborn errors of metabolism. These conditions are often unresponsive to treatment with conventional antiepileptic drugs. Six children with pyridox(am)ine-5′-phosphate oxidase (PNPO) deficiency presented with neonatal epileptic encephalopathy. Two were treated with pyridoxal 5′-phosphate (PLP) within the first month of life and showed normal development or moderate psychomotor retardation thereafter. Four children with late or no treatment died or showed severe mental handicap. All of the children showed atypical biochemical findings. Prompt treatment with PLP in all neonates and infants with epileptic encephalopathy should become mandatory, permitting normal development in at least some of those affected with PNPO deficiency.

Seizures and paroxysmal events: symptoms pointing to the diagnosis of pyridoxine-dependent epilepsy and pyridoxine phosphate oxidase deficiency

Aim  We report on seizures, paroxysmal events, and electroencephalogram (EEG) findings in four female infants with pyridoxine‐dependent epilepsy (PDE) and in one female with pyridoxine phosphate oxidase deficiency (PNPO).

Neonatal seizures with tonic clonic sequences and poor developmental outcome

Seizures consisting of a tonic followed by a clonic phase have rarely been described in neonates and are not included in the current classifications of neonatal seizures. Our video archive of 105 neonates with seizures or suspected seizures revealed six neonates with such tonic clonic or tonic myoclonic sequences. Two of those neonates had pyridoxine dependent seizures. The other four neonates had drug refractory seizures and demonstrated similarities in electro-clinical pattern, clinical course and outcome. Their seizures started with tonic posturing and after 10-20s tonic posturing was superimposed by focal or multifocal cloni or myocloni. Ictal EEG started with voltage attenuation followed by bilateral or alternating focal epileptic discharges. The interictal EEG was abnormal. One child died, while the other three children became seizure free but had severe motor delay and mental retardation. In one of those three children, a de novo missense mutation was detected in the voltage gated potassium channel gene KCNQ2, indicating a genetic relationship between drug refractory neonatal seizures of unknown etiology with tonic clonic or myoclonic sequences and the well-known syndrome of benign familial neonatal convulsions (BFNC).

Serum and CSF levels of neuron-specific enolase (NSE) in cardiac surgery with cardiopulmonary bypass: a marker of brain injury?

We investigated whether neuron-specific enolase (NSE) in serum or cerebrospinal fluid (CSF) reflects subtle or manifest brain injury in children undergoing cardiac surgery using cardiopulmonary bypass (CPB). NSE was measured in serum (s-NSE) before, and up to, 102 h after surgery in 27 children undergoing cardiac surgery with CPB. In 11 children, CSF-NSE was also measured 48 or 66 h post-surgery. As erythrocytes contain NSE, hemoglobin concentration in the samples was determined spectrophotometrically at 550 nm (cut-off limit: absorbance 0.4 = 560 mg/l) in 14 children and in a further 13 children by spectroscopic multicomponent analysis (cut-off limit 5 micromol/l = 80 mg/l). One hundred and one of 214 post-operative serum samples (47%) had to be discarded because of hemolysis (18% spectrophotometrically at 550 nm and 88% with spectroscopic multicomponent analysis). On the first and second post-operative day, the median s-NSE values were significantly higher when compared with samples taken after 54 h or longer (P = 0.008 and P = 0.002). All CSF-NSE levels were within the normal range and below the s-NSE measured in the same patient. Although in our study elevated s-NSE seems to indicate brain injury in CPB-surgery, the low concentration of NSE in the post-operative CSF of 11 children puts the neuronal origin of s-NSE in question. NSE from other non-neuronal tissues probably contributes to the elevated s-NSE. Additionally, normal post-operative CSF-NSE values in two children with post-operative neurological sequelae might question the predictive value of CSF-NSE with regard to brain injury.

Adverse Effects of Vigabatrin in Angelman Syndrome

Summary: New antiepileptic drugs designed for enhancing GABAergic inhibition, such as vigabatrin (VGB) may be effective in Angelman syndrome (AS), because associated convulsions could be related to a reduced GABA‐receptor density or receptor abnormality. From our preliminary experiences in four children with AS treated with VGB, we conclude that it may induce and increase seizures in patients with AS.

Proven Startle-provoked Epileptic Seizures in Childhood: Semiologic and Electrophysiologic Variability

Summary:  Purpose: To delineate further the clinical and electrophysiologic features of proven startle‐provoked epileptic seizures (SPESs) in children.

Safety and effectiveness of hormonal treatment versus hormonal treatment with vigabatrin for infantile spasms (ICISS): a randomised, multicentre, open-label trial

BACKGROUND Infantile spasms constitutes a severe infantile epilepsy syndrome that is difficult to treat and has a high morbidity. Hormonal therapies or vigabatrin are the most commonly used treatments. We aimed to assess whether combining the treatments would be more effective than hormonal therapy alone. METHODS In this multicentre, open-label randomised trial, 102 hospitals (Australia [three], Germany [11], New Zealand [two], Switzerland [three], and the UK [83]) enrolled infants who had a clinical diagnosis of infantile spasms and a hypsarrhythmic (or similar) EEG no more than 7 days before enrolment. Participants were randomly assigned (1:1) by a secure website to receive hormonal therapy with vigabatrin or hormonal therapy alone. If parents consented, there was an additional randomisation (1:1) of type of hormonal therapy used (prednisolone or tetracosactide depot). Block randomisation was stratified for hormonal treatment and risk of developmental impairment. Parents and clinicians were not masked to therapy, but investigators assessing electro-clinical outcome were masked to treatment allocation. Minimum doses were prednisolone 10 mg four times a day or intramuscular tetracosactide depot 0·5 mg (40 IU) on alternate days with or without vigabatrin 100 mg/kg per day. The primary outcome was cessation of spasms, which was defined as no witnessed spasms on and between day 14 and day 42 from trial entry, as recorded by parents and carers in a seizure diary. Analysis was by intention to treat. The trial is registered with The International Standard Randomised Controlled Trial Number (ISRCTN), number 54363174, and the European Union Drug Regulating Authorities Clinical Trials (EUDRACT), number 2006-000788-27. FINDINGS Between March 7, 2007, and May 22, 2014, 766 infants were screened and, of those, 377 were randomly assigned to hormonal therapy with vigabatrin (186) or hormonal therapy alone (191). All 377 infants were assessed for the primary outcome. Between days 14 and 42 inclusive no spasms were witnessed in 133 (72%) of 186 patients on hormonal therapy with vigabatrin compared with 108 (57%) of 191 patients on hormonal therapy alone (difference 15·0%, 95% CI 5·1-24·9, p=0·002). Serious adverse reactions necessitating hospitalisation occurred in 33 infants (16 on hormonal therapy alone and 17 on hormonal therapy with vigabatrin). The most common serious adverse reaction was infection occurring in five infants on hormonal therapy alone and four on hormonal therapy with vigabatrin. There were no deaths attributable to treatment. INTERPRETATION Hormonal therapy with vigabatrin is significantly more effective at stopping infantile spasms than hormonal therapy alone. The 4 week period of spasm cessation required to achieve a primary clinical response to treatment suggests that the effect seen might be sustained, but this needs to be confirmed at the 18 month follow-up. FUNDING The Castang Foundation, Bath Unit for Research in Paediatrics, National Institute of Health Research, the Royal United Hospitals Bath NHS Foundation Trust, the BRONNER-BENDUNG Stifung/Gernsbach, and University Childrens Hospital Zurich.

Glutamine supplementation in a child with inherited GS deficiency improves the clinical status and partially corrects the peripheral and central amino acid imbalance

Glutamine synthetase (GS) is ubiquitously expressed in mammalian organisms and is a key enzyme in nitrogen metabolism. It is the only known enzyme capable of synthesising glutamine, an amino acid with many critical roles in the human organism. A defect in GLUL, encoding for GS, leads to congenital systemic glutamine deficiency and has been described in three patients with epileptic encephalopathy. There is no established treatment for this condition.Here, we describe a therapeutic trial consisting of enteral and parenteral glutamine supplementation in a four year old patient with GS deficiency. The patient received increasing doses of glutamine up to 1020 mg/kg/day. The effect of this glutamine supplementation was monitored clinically, biochemically, and by studies of the electroencephalogram (EEG) as well as by brain magnetic resonance imaging and spectroscopy.Treatment was well tolerated and clinical monitoring showed improved alertness. Concentrations of plasma glutamine normalized while levels in cerebrospinal fluid increased but remained below the lower reference range. The EEG showed clear improvement and spectroscopy revealed increasing concentrations of glutamine and glutamate in brain tissue. Concomitantly, there was no worsening of pre-existing chronic hyperammonemia.In conclusion, supplementation of glutamine is a safe therapeutic option for inherited GS deficiency since it corrects the peripheral biochemical phenotype and partially also improves the central biochemical phenotype. There was some clinical improvement but the patient had a long standing severe encephalopathy. Earlier supplementation with glutamine might have prevented some of the neuronal damage.

Familial West syndrome and dystonia caused by an Aristaless related homeobox gene mutation

Boys with unexplained West syndrome should be examined for a mutation in the Aristaless related homeobox gene, especially, when the family history is positive for mental retardation and epilepsy. X-linked West syndrome is very rare. We report on two brothers with West syndrome and dystonia with polyalanine expansion of the Aristaless related homeobox gene (ARX). The index patient (Fig. 1a; III-2) was the second child of non-consanguineous parents, born in 2001 at term, after an uneventful pregnancy and delivery (birth weight 3659 g, 75th percentile; length 51 cm, 75th percentile; head circumference 35 cm, 50th percentile). At the age of 3 months he developed infantile spasms and a hypsarrhythmic EEG pattern. He promptly responded to vigabatrin therapy. At 5 months a generalised dystonia, i.e. increased muscle tone with dystonic posturing of limbs, was evident. At the age of 3 years, he is able to walk a few steps with help and grasping objects is very difficult. He has no expressive speech. The elder brother of the index patient (Fig. 1a; III-1) was born in 1996 by caesarean section because of neonatal macrosomia (birth weight 4200 g, 90th percentile; length 53 cm, 90th percentile; head circumference 38 cm, >90th percentile). At the age of 3 months he showed dystonic movements and marked truncal hypotonia. One month later he developed infantile spasms and a hypsarrhythmic EEG pattern. He did not respond to vigabatrin, but to ACTH. At the age of 8 years he is wheel-chair bound, not talking, grasping objects is not possible. In both children metabolic tests and neuroimaging (MRI) were normal. Actually, both brothers suffer from a severe dystonia, mental impairment and rare generalised tonic-clonic seizures (the older brother), treated with valproic acid. The family history was remarkable. In the maternal uncle (Fig. 1a; II-3, now 37 years old), spastic tetraplegia, mental retardation and epilepsy have been present since early infancy. In retrospect, the epilepsy syndrome could not be classified. MRI was not performed in this uncle, the mother or the grandmother. From the pedigree and the clinical findings we suspected a mutation in the ARX gene. Following informed consent, a sequence analysis of the coding region and flanking intronic sequences of the ARX gene was performed. The male proband (index patient; Fig. 1a; III-2) as well as his brother and uncle were found to be hemizygous for a 21 bp GCG repeat expansion in exon 2 of the ARX gene c.333_334ins(GCG)7, which expands the first of four alanine tracts from normally 16 to 23 alanine residues (Fig. 1b,c). Both the mother (Fig. 11; II-2) and the maternal grandmother (Fig. 1a; I-2) were identified as heterozygous mutation carriers using an optimised fluorescence-based PCR assay. Mutations in the ARX gene have been found in a broad spectrum of disorders including X-linked infantile spasms (ISSX)/West syndrome, mental retardation [2], ataxia and dystonia (Partington syndrome), syndromic and non-syndromic forms of mental retardation, myoclonic epilepsy and X-linked lissencephaly with abnormal genitalia (XLAG) [5, 6,8]. The mutation found in our Swiss family, which is not related to previously reported families, has been described before in boys with infantile spasms and normal MRI, severe mental and motor retardation [7]. In addition to Partington syndrome, dystonia was described in a few unpublished Australian and Norwegian cases [6], but G. Wohlrab (&) AE B. Schmitt AE E. Boltshauser Department of Neuropaediatrics and Neurophysiology, University Children’s Hospital, Steinwiesstrasse 75, 8032 Zurich, Switzerland E-mail: gabriele.wohlrab@kispi.unizh.ch Tel.: +41-1-2667701 Fax: +41-1-2667165