TANGO2: expanding the clinical phenotype and spectrum of pathogenic variants

Jennifer N. Dines, Katie Golden-Grant, Amy LaCroix, Alison M. Muir, Dianne Laboy Cintrón, Kirsty McWalter, Megan T. Cho, Angela Sun, J. Lawrence Merritt, Jenny Thies, Dmitriy Niyazov, Barbara Burton, Katherine Kim, Leah Fleming, Rachel Westman, Peter Karachunski, Joline Dalton, Alice Basinger, Can Ficicioglu, Ingo Helbig, Manuela Pendziwiat, Hiltrud Muhle, Katherine L. Helbig, Almuth Caliebe, René Santer, Kolja Becker, Sharon Suchy, Ganka Douglas, Francisca Millan, Amber Begtrup, Kristin G. Monaghan, Heather C. Mefford

TANGO2-related disorders were first described in 2016 and prior to this publication, only 15 individuals with TANGO2-related disorder were described in the literature. Primary features include metabolic crisis with rhabdomyolysis, encephalopathy, intellectual disability, seizures, and cardiac arrhythmias. We assess whether genotype and phenotype of TANGO2-related disorder has expanded since the initial discovery and determine the efficacy of exome sequencing (ES) as a diagnostic tool for detecting variants. We present a series of 14 individuals from 11 unrelated families with complex medical and developmental histories, in whom ES or microarray identified compound heterozygous or homozygous variants in TANGO2. The initial presentation of patients with TANGO2-related disorders can be variable, including primarily neurological presentations. We expand the phenotype and genotype for TANGO2, highlighting the variability of the disorder. TANGO2-related disorders can have a more diverse clinical presentation than previously anticipated. We illustrate the utility of routine ES data reanalysis whereby discovery of novel disease genes can lead to a diagnosis in previously unsolved cases and the need for additional copy-number variation analysis when ES is performed.