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.

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.

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