Clinical spectrum of early-onset epileptic encephalopathies associated with STXBP1 mutations.

OBJECTIVES: Heterozygous mutations in STXBP1, encoding the syntaxin binding protein 1, have recently been identified in Ohtahara syndrome, an epileptic encephalopathy with very early onset. In order to explore the phenotypic spectrum associated with STXBP1 mutations, we analyzed a cohort of patients with unexplained early-onset epileptic encephalopathies. METHODS: We collected and clinically characterized 106 patients with early-onset epileptic encephalopathies. Mutation analysis of the STXBP1 gene was done using sequence analysis of the exon and intron-exon boundaries and multiplex amplification quantification to detect copy number variations. RESULTS: We identified 4 truncating mutations and 2 microdeletions partially affecting STXBP1 in 6 of the 106 patients. All mutations are predicted to abolish STXBP1 function and 5 mutations were proven to occur de novo. None of the mutation-carrying patients had Ohtahara syndrome. One patient was diagnosed with West syndrome at disease onset, while the initial phenotype of 5 further patients did not fit into a specific recognized epilepsy syndrome. Three of these patients later evolved to West syndrome. All patients had severe to profound mental retardation, and ataxia or dyskinetic movements were present in 5 patients. CONCLUSION: This study shows that mutations in STXBP1 are not limited to patients with Ohtahara syndrome, but are also present in 10% (5/49) of patients with an early-onset epileptic encephalopathy that does not fit into either Ohtahara or West syndrome and rarely in typical West syndrome. STXBP1 mutational analysis should be considered in the diagnostic evaluation of this challenging group of patients.

Gorlin-Goltz syndrome in a child: case report and clinical review.

Gorlin-Goltz syndrome is a rare autosomal dominant disorder that involves multiple organ systems, including the skin, skeleton and jaws. We report the case of a mild mentally retarded 7-year-old boy who was referred with a swelling of his left mandible. Imaging studies showed a unilocular well-defined lytic mandibular lesion, calcifications of the falx, bifid ribs and fusion anomalies of the ribs. The mandibular lesion was treated with surgical decompression and proved to represent a keratocyst on histological examination. Further clinical examination revealed cutaneous lesions, Sprengel deformity, pectus excavatum and facial dysmorphism. Based on the combination of imaging and clinical findings the diagnosis of Gorlin-Goltz syndrome was made. This was confirmed by genetic tests. During three-year follow-up the boy presented with recurrent and multiple odontogenic keratocysts. The occurrence of multiple and recurrent keratocysts at young age, should alert the radiologist to the potential diagnosis of an underlying Gorlin-Goltz syndrome. This paper reviews the imaging findings in Gorlin-Goltz syndrome, with emphasis on maxillofacial imaging.