Expanding the TBL1XR1 Disease Spectrum: Generalized Dystonia Associated with a New Genetic Variant

Maximilian Johannes Löw ¹, Felix Bernsdorff ¹, Christiane Weinrich ¹, Saskia Biskup ², Jerome Jüngling ², Christoph van Riesen ^{# 1 3}, Fabian Maass ^{# 1}

Background: A growing number of identified genes increasingly reveal genetic overlaps between neurodevelopmental disorders and combined dystonia syndromes.

Case report: We report a 61-year-old man with a neurodevelopmental disorder, mild ataxic signs and generalized dystonia who had been misdiagnosed with cerebral palsy for 40 years. Whole-exome sequencing identified a novel heterozygous pathogenic frameshift variant in TBL1XR1.

Discussion: TBL1XR1 variants are classically associated with Pierpont syndrome and autism spectrum disorder. Although movement disorders have been reported, this case suggests generalized dystonia as a possible additional manifestation. It highlights the value of retrospective genetic phenotyping and next-generation sequencing in adults with long-standing neurodevelopmental diagnoses.

Keywords: Pierpont syndrome; TBL1XR1; generalized dystonia.