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Abstract

We thank Dr. Jaaken for his insightful discussion of adenylosuccinase deficiency as a cause of neonatal seizures. Our review was intended to offer an overview of metabolic disorders presenting with isolated neonatal seizures, i.e., neonatal seizures not associated with other characteristic abnormalities. Dr. Jaaken is correct in observing that neonatal seizures may constitute an atypical presentation of this rare disease, with six cases reported in the literature [ [1] Mouchegh K. Zikánová M. Hoffmann G.F. et al. Lethal fetal and early neonatal presentation of adenylosuccinate lyase deficiency: Observation of 6 patients in 4 families. J Pediatr. 2007; 150: 57-61 Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar ]. However, the severe form of adenylosuccinase deficiency that presents with neonatal seizures is often accompanied by severe hypotonia, intrauterine growth retardation, and magnetic resonance imaging abnormalities that are variable but that generally include dysmyelination [ [2] Jurecka A. Jurkiewicz E. Tylki-Szymanska A. Magnetic resonance imaging of the brain in adenylosuccinate lyase deficiency: A report of seven cases and a review of the literature. Eur J Pediatr. 2012; 171: 131-138 Crossref PubMed Scopus (19) Google Scholar ]. In addition, a characteristic facial dysmorphism has been described [ [3] Holder-Espinasse M. Bourrouillou G. Ceballos-Picot I. et al. Towards a suggestive facial dysmorphism in adenylosuccinate lyase deficiency?. J Med Genet. 2002; 39: 440-442 Crossref PubMed Scopus (12) Google Scholar ]. We agree that screening for disorders of purine metabolism, including adenylosuccinase deficiency, is indicated in the evaluation of neonatal seizures without a clear etiology, and cerebrospinal fluid succinyl adenosine and urine purine panels, which are clinically available, should be added to our diagnostic algorithm. However, we do urge caution in the interpretation of the modified Bratton-Marshall test, because false-positive results are common for a variety of reasons, including exposure to benzodiazepines, which are commonly used in the treatment of neonatal seizures. Isolated Neonatal Seizures: Adenylosuccinase Deficiency is Another Cause!Pediatric NeurologyVol. 47Issue 3PreviewI read with great interest the very useful review “Isolated Neonatal Seizures: When to Suspect Inborn Errors of Metabolism” by Ficicioglu and Bearden [1]. I would like to add adenylosuccinase deficiency to their causes for suspicion. This genetic, mainly neurologic disorder of the de novo purine synthesis was first reported in 1984 [2]. Most of the approximately 60 reported patients demonstrate variable associations of moderate to severe psychomotor retardation, epilepsy after their first years, autistic features, and growth retardation [3]. Full-Text PDF