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Dystonia research focuses on the identification of converging biological pathways, allowing to define molecular drivers that serve as treatment targets. We summarize evidence supporting the concept that aberrations in purine metabolism intersect with dystonia pathogenesis. The recent discovery of IMPDH2-related dystonia introduced a gain-of-function paradigm in purinergic system defects, offering new perspectives to understand purine-pool imbalances in brain diseases. We discuss commonalities between known dystonia-linked mechanisms and mechanisms emerging from studies of purine metabolism disorders including Lesch-Nyhan disease. Together, we hypothesize that a greater appreciation of the relevance of purine perturbances in dystonia can offer fresh avenues for therapeutic intervention. ANN NEUROL 2025., (© 2025 The Author(s). Annals of Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Polynucleotide kinase phosphatase (PNKP), encoded by the PNKP gene, is a DNA processing enzyme involved in double-strand break and single-strand break repair pathways, which are essential for genome stability and for the correct development and maintenance of human nervous system. PNKP biallelic loss-of-function variants have been associated with a broad spectrum of neurological anomalies, ranging from congenital microcephaly with intellectual disability and seizures (MCSZ), to later onset forms of ataxia-oculomotor apraxia (AOA4) or peripheral neuropathy (CMT2B2). We report the atypical clinical manifestations of a patient with severe microcephaly, short stature, developmental delay, conductive hearing loss, and tracheoesophageal malformation, in the absence of seizures. Whole exome sequencing analysis identified two novel, compound heterozygous splice-site variants in the PNKP gene (NM_007254.4): c.1448+1G > A and c.199-8_199-5del. To demonstrate the effect of both variants on the splicing process and prove their pathogenicity, we performed a hybrid minigene assay, which successfully highlighted a deleterious impact on the transcript, particularly regarding the c.199-8_199-5del variant. The uncommon clinical features of the proband and the identification of two newly associated pathogenic variants add further evidence to the allelic and phenotypic heterogeneity of the PNKP locus., (© 2024 The Author(s). American Journal of Medical Genetics Part B: Neuropsychiatric Genetics published by Wiley Periodicals LLC.)

Dystonia is a rare-disease trait for which large-scale genomic investigations are still underrepresented. Genetic heterogeneity among patients with unexplained dystonia warrants interrogation of entire genome sequences, but this has not yet been systematically evaluated. To significantly enhance our understanding of the genetic contribution to dystonia, we (re)analyzed 2,874 whole-exome sequencing (WES), 564 whole-genome sequencing (WGS), as well as 80 fibroblast-derived proteomics datasets, representing the output of high-throughput analyses in 1,990 patients and 973 unaffected relatives from 1,877 families. Recruitment and precision-phenotyping procedures were driven by long-term collaborations of international experts with access to overlooked populations. By exploring WES data, we found that continuous scaling of sample sizes resulted in steady gains in the number of associated disease genes without plateauing. On average, every second diagnosis involved a gene not previously implicated in our cohort. Second-line WGS focused on a subcohort of undiagnosed individuals with high likelihood of having monogenic forms of dystonia, comprising large proportions of patients with early onset (81.3%), generalized symptom distribution (50.8%) and/or coexisting features (68.9%). We undertook extensive searches for variants in nuclear and mitochondrial genomes to uncover 38 (ultra)rare diagnostic-grade findings in 37 of 305 index patients (12.1%), many of which had remained undetected due to methodological inferiority of WES or pipeline limitations. WGS-identified elusive variations included alterations in exons poorly covered by WES, RNA-gene variants, mitochondrial-DNA mutations, small copy-number variants, complex rearranged genome structure, and short tandem repeats. For improved variant interpretation in WGS-inconclusive cases, we employed systematic integration of quantitative proteomics. This aided in verifying diagnoses related to technically challenging variants and in upgrading a variant of uncertain significance (3 of 70 WGS-inconclusive index patients, 4.3%). Further, unsupervised proteomic outlier-analysis supplemented with transcriptome sequencing revealed pathological gene underexpression induced by transcript disruptions in three more index patients with underlying (deep) intronic variants (3/70, 4.3%), highlighting the potential for targeted antisense-oligonucleotide therapy development. Finally, trio-WGS prioritized a de-novo missense change in the candidate PRMT1, encoding a histone-methyltransferase. Data-sharing strategies supported the discovery of three distinct PRMT1 de-novo variants in four phenotypically similar patients, associated with loss-of-function effects in in-vitro assays. This work underscores the importance of continually expanding sequencing cohorts to characterize the extensive spectrum of gene aberrations in dystonia. We show that a pool of unresolved cases is amenable to WGS and complementary multi-omic studies, directing advanced etiopathological concepts and future diagnostic-practice workflows for dystonia., (© The Author(s) 2025. Published by Oxford University Press on behalf of the Guarantors of Brain.)