# Tremor-Dominant Movement Disorder in ANKRD11- Associated KBG Syndrome

## TL;DR

This paper reports a case linking ANKRD11 mutations to tremor-dominant movement disorders in KBG syndrome.

## Contribution

The study expands the known clinical features of KBG syndrome to include movement disorders.

## Key findings

- A patient with an ANKRD11 frameshift variant exhibited tremor-dominant movement disorder.
- The patient showed rest, intention, and postural tremors, voice tremor, and signs of ataxia.
- This case supports considering ANKRD11 variants in diagnosing combined tremor syndromes.

## Abstract

KBG syndrome is a monogenic disorder caused by heterozygous pathogenic variants in ANKRD11. A recent single-case study suggested that the clinical spectrum of KBG syndrome, classically defined by distinctive craniofacial traits and developmental delay, may include movement disorders.

We report a 24-year-old patient harboring a pathogenic de novo ANKRD11 frameshift variant. The phenotype was dominated by a progressive tremor-dominant movement disorder, characterized by rest, intention and postural tremor of the hands, voice tremor, head and tongue tremor, increased muscle tone and signs of ataxia. Additionally, the patient had a history of mild developmental delay and epilepsy.

Adding to the recently described individual, our present patient highlights the relevance of movement disorders as a clinically relevant manifestation of KBG syndrome. ANKRD11 pathogenic variants should be considered in the differential diagnosis of combined tremor syndromes.