Genotype-Phenotype Relations for the Dystonia-Parkinsonism Genes GLB1, SLC6A3, SLC30A10, SLC39A14, and PLA2G6: MDSGene Systematic Review.

The Movement Disorders Society recommends the DYT/PARK prefix for genes where dystonia and parkinsonism are prominent in approximately half or more of patients. This systematic review explores the genotype-phenotype correlations of GLB1, SLC6A3, SLC30A10, PLA2G6, and SLC39A14-recently classified as DYT SLC39A14 and historically linked to dystonia-parkinsonism. We searched PubMed and the Human Gene Mutation Database using standardized terms, including English-language, peer-reviewed publications up to February 2024. Following the MDSGene protocol, we extracted individual-level data on patients with biallelic pathogenic variants and at least one movement disorder. Features were marked "missing" if not explicitly reported. Of 1828 articles, 128 were eligible. We identified 386 patients and 262 variants. The median age at onset was 3 years for GLB1, 3 months for SLC6A3, 2.5 years for SLC30A10, 1.5 years for SLC39A14, and 16 years for PLA2G6. Missing data may reflect underreporting of negative findings. Case reports/serie, may bias toward atypical presentations. Our analysis showed dystonia-parkinsonism predominates in SLC6A3 and PLA2G6, while GLB1, SLC30A10, and SLC39A1 show predominantly dystonic phenotypes with a low frequency of parkinsonism. Ataxia was common in GLB1 and PLA2G6. Awareness of these phenotypes is essential for early diagnosis and intervention, particularly in treatable conditions like SLC30A10 or SLC39A14. The predominantly dystonic phenotype in GLB1, SLC30A10, and SLC39A14 suggest that the DYT prefix may be more appropriate, highlighting the need to reconsider their nomenclature, and the importance of systematic reviews.