A Child with KMT2B-Related Acute-Onset Dystonia: Clinical Pointers to Molecular Diagnosis

Abstract Dystonia is common extrapyramidal presentation of neurological problems in childhood. The causes could range from infectious, autoimmune, drug-induced, or genetic in origin. Genetic causes are rare in origin but could masquerade the common causes. Recently, KMT2B-related dystonia has been identified as a common genetic cause of dystonia in childhood. We present a case of a 3.5-year-old with 18 months of follow-up, who was diagnosed with KMT2B-related dystonia and managed with antidystonia drugs to an acceptable level where she could perform her day-to-day work with ease. Here, we highlight certain clinical pointers of the disease and the need of special genetic test in diagnosing such cases. We also tabulated the three previously reported Indian cases and compared their parameter with ours.