Homozygous TANGO2 Single Nucleotide Variants Presenting with Additional Manifestations Resembling Alternating Hemiplegia of Childhood-Expanding the Phenotype of a Recently Reported Condition

Case We report a 15-year-old Indian girl born to a consanguineous couple, who presented with epilepsy, developmental delay, neuroregression, and episodes of alternating hemiparesis. In addition, she had one episode of rhabdomyolysis at the age of 7 years. Extensive genetic and metabolic work up through the years was unrevealing. Eventually a trio whole exome sequencing (WES) revealed homozygous single nucleotide variants in TANGO2 gene. Discussion TANGO2 related recurrent metabolic crises with encephalomyopathy and cardiac arrhythmias were described very recently and only 15 cases were reported in literature at the time of writing. Alternating hemiplegia of childhood which was seen in our patient, has not been described in previous patients with TANGO2 mutation, and thereby expands the emerging phenotypic spectrum of this novel entity. This report also reiterates the utility of WES in diagnosing newly recognized neurogenetic conditions.