Not to Miss: Intronic Variants, Treatment, and Review of the Phenotypic Spectrum in VPS13D-Related Disorder

Martje G. Pauly, Norbert Brüggemann, Stephanie Efthymiou, Anne Grözinger, Sokhna Haissatou Diaw, Viorica Chelban, Valentina Turchetti, Barbara Vona, Vera Tadic, Henry Houlden, Alexander Münchau, Katja Lohmann*

*Corresponding author for this work
4 Citations (Scopus)

Abstract

VPS13D is one of four human homologs of the vacuolar sorting protein 13 gene (VPS13). Biallelic pathogenic variants in the gene are associated with spastic ataxia or spastic paraplegia. Here, we report two patients with intronic pathogenic variants: one patient with early onset severe spastic ataxia and debilitating tremor, which is compound-heterozygous for a canonical (NM_018156.4: c.2237−1G > A) and a non-canonical (NM_018156.4: c.941+3G>A) splice site variant. The second patient carries the same non-canonical splice site variant in the homozygous state and is affected by late-onset spastic paraplegia. We confirmed altered splicing as a result of the intronic variants and demonstrated disturbed mitochondrial integrity. Notably, tremor in the first patient improved significantly by bilateral deep brain stimulation (DBS) in the ventralis intermedius (VIM) nucleus of the thalamus. We also conducted a literature review and summarized the phenotypical spectrum of reported VPS13D-related disorders. Our study underscores that looking for mutations outside the canonical splice sites is important not to miss a genetic diagnosis, especially in disorders with a highly heterogeneous presentation without specific red flags.

Original languageEnglish
Article number1874
JournalInternational Journal of Molecular Sciences
Volume24
Issue number3
ISSN1661-6596
DOIs
Publication statusPublished - 02.2023

Research Areas and Centers

  • Research Area: Medical Genetics

DFG Research Classification Scheme

  • 206-06 Molecular and Cellular Neurology and Neuropathology

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