Trigeminal Neuralgia in a 12-Month-Old Boy With Dandy-Walker Malformation and Homozygous Pathogenic TOPORS Variant.

A 12-month-old boy with a Dandy-Walker malformation (DWM) presented with a 2-month history of lip chewing and face rubbing such that disfiguring ulcerations were present on his lips and right eye. The persistently frequent but intermittent behaviors during wakefulness lasted minutes at a time numerous times each hour of the day and were associated with pronounced irritability relieved only with sleep. Analgesics were unhelpful. Carbamazepine at anticonvulsant doses was deployed for a presumptive diagnosis of trigeminal neuralgia (TN), which not only resulted in an estimated 90% reduction of the self-injurious behaviors after a month, but also enabled the lip and right eye lesions to completely heal over the next several months. Genetic testing (exome sequencing [ES]) demonstrated a homozygous pathogenic variant in the TOPORS gene (c.29 C>A, p.P10Q, # OMIM 609507). We review the history of TN and Dandy-Walker syndrome (DWS) and speculate on their relationship in this patient, the youngest such reported incidence of TN in the literature while adding additional clinical features to the continuum of TOPORS phenotypes.