DOI: 10.1002/mgg3.1647; PMCID: PMC8123744
BACKGROUND: Benign hereditary chorea (BHC) is an autosomal dominant disorder characterized by early-onset non-progressive involuntary movements. Although NKX2-1 mutations or deletions are the cause of BHC, some BHC families do not have pathogenic alterations in the NKX2-1 gene, indicating that mutations of non-coding regulatory elements of NKX2-1 may also play a role.
METHODS AND RESULTS: By using whole-genome microarray analysis, we identified a 117 Kb founder deletion in three apparently unrelated BHC families that were negative for NKX2-1 sequence variants. Targeted next generation sequencing analysis confirmed the deletion and showed that it was part of a complex local genomic rearrangement. In addition, we also detected a 648 Kb de novo deletion in an isolated BHC case. Both deletions are located downstream from NKX2-1 on chromosome 14q13.2-q13.3 and share a 33 Kb smallest region of overlap with six previously reported cases. This region has no gene but contains multiple evolutionarily highly conserved non-coding sequences.
CONCLUSION: We propose that the deletion of potential regulatory elements necessary for NKX2-1 expression in this critical region is responsible for BHC phenotype in these patients, and this is a novel disease-causing mechanism for BHC.
Mol Genet Genomic Med
NKX2-1; benign hereditary chorea; chromosome 14q13.2-q13.3; copy number variations; non-coding regulatory elements
Liao J, Coffman KA, Locker J, et al. Deletion of conserved non-coding sequences downstream from NKX2-1: A novel disease-causing mechanism for benign hereditary chorea. Mol Genet Genomic Med. 2021;9(4):e1647. doi:10.1002/mgg3.1647