Disco-Interacting Protein 2 Homolog B CGG Repeat Expansion in Siblings with Neurodevelopmental Disability and Progressive Movement Disorder.

BACKGROUND

Trinucleotide repeat expansions are an emerging class of genetic variants associated with various movement disorders. Unbiased genome-wide analyses can reveal novel genotype-phenotype associations and provide a diagnosis for patients and families.

OBJECTIVE

The aim was to identify the genetic cause of a severe progressive movement disorder phenotype in 2 affected brothers.

METHODS

A family of 2 affected brothers and unaffected parents had extensive phenotyping since birth. Whole-genome and long-read sequencing methods characterized genetic variants and methylation status.

RESULTS

Two male siblings with a CGG repeat expansion in the 5'-untranslated region (UTR) of disco-interacting protein 2 homolog B (DIP2B) presented with a novel DIP2B phenotype, including neurodevelopmental disability, dysmorphic traits, and a severe progressive movement disorder (chorea, dystonia, and ataxia).

CONCLUSIONS

This is the first report of a severe progressive movement disorder phenotype associated with a CGG repeat expansion in the DIP2B 5'-UTR. © 2025 International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.