An Important Pediatric Stroke Mimic: Hemiplegic Migraine.

Stroke is relatively rare in children but has become increasingly recognized clinically. Hemiplegic migraine (HM) is a rare subtype of migraine, with attacks typically beginning in childhood or adolescence. Attacks are characterized by migraine headaches and motor weakness, which develop over several minutes. HM may therefore mimic acute stroke; however, symptoms last less than an hour and resolve spontaneously, often without sequela.1-4 Distinction between these entities is important due to their different urgency and management. Neuroimaging is indispensible in working up patients presenting to the Emergency Department with stroke-like symptoms and can be used to distinguish between infarction and HM.

Chromosome band 7q34 deletions resulting in KIAA1549-BRAF and FAM131B-BRAF fusions in pediatric low-grade Gliomas.

The majority of pediatric low-grade gliomas (LGGs) are characterized by constitutive activation of the mitogen-activated protein kinase (MAPK) pathway through various mechanisms including BRAF mutations, inactivation of NF1, and KIAA1549-BRAF and FAM131B-BRAF fusions. The KIAA1549-BRAF fusion typically results from a 2.0 Mb tandem duplication in chromosome band 7q34. In the present study, single nucleotide polymorphism (SNP)-based array analysis of three LGGs demonstrated deletions in 7q34 that resulted in a BRAF fusion. Case 1 was likely a pilocytic astrocytoma (PA) with three deletions in 7q33q34 and an exon 15-9 KIAA1549-BRAF fusion. SNP array analysis of case 2, a possible dysembryoplastic neuroepithelial tumor (DNT), revealed a 2.6 Mb deletion, which included the 5' end of BRAF and extended to the 3' end of FAM131B. In case 3, deletions involving BRAF and FAM131B were observed in both a primary and a recurrent PA. RNA-based sequence analysis of cases 2 and 3 confirmed a fusion between FAM131B exon 2 and BRAF exon 9. The presence of fusion transcripts in these three LGGs highlights the utility of SNP array analysis to identify deletions that are suggestive of fusion proteins. BRAF fusions can result from multiple non-overlapping deletions, suggesting various complex mechanisms of formation.