Downloaded from molecularcasestudies.cshlp.org on October 6, 2021 - Published by Cold Spring Harbor Laboratory Press Compound heterozygous SLC19A3 mutations further refine the critical promoter region for biotin-thiamine-responsive basal ganglia disease Whitney Whitford1,8, Isobel Hawkins1, Emma Glamuzina2, Francessa Wilson3, Andrew Marshall4, Fern Ashton5, Donald R. Love5, Juliet Taylor6, Rosamund Hill7, Klaus Lehnert1,8, Russell G. Snell1,8, Jessie C. Jacobsen1,8 1School of Biological Sciences, The University of Auckland, New Zealand 2Adult and Paediatric National Metabolic Service, Starship Children’s Hospital, New Zealand 3Department of Paediatric Radiology, Starship Children’s Hospital, New Zealand 4Department of Paediatrics and Child Health, Wellington Hospital, New Zealand 5Diagnostic Genetics LabPLUS, Auckland City Hospital, Auckland, New Zealand 6Genetic Health Service New Zealand, Auckland City Hospital, New Zealand 7Department of Neurology, Auckland City Hospital, New Zealand 8Centre for Brain Research, The University of Auckland, New Zealand corresponding author’s e-mail:
[email protected] ABSTRACT (250 words max) Mutations in the gene SLC19A3 result in thiamine metabolism dysfunction syndrome 2, also known as biotin-thiamine-responsive basal ganglia disease (BTBGD). This neurometabolic disease typically presents in early-childhood with progressive neurodegeneration, including confusion, seizures, and dysphagia, advancing to coma and death. Treatment is possible via supplement of biotin and/or thiamine, with early treatment resulting in significant life-long improvements. Here we report two siblings who received a refined diagnosis of BTBGD following whole genome sequencing. Both children inherited compound heterozygous mutations from unaffected parents; a missense single nucleotide variant (p.G23V) in the first transmembrane domain of the protein, and a 4,808 bp deletion in exon 1 encompassing the 5’ UTR and critical promoter region.