RT Journal Article T1 Parkinsonism and spastic paraplegia type 7: Expanding the spectrum of mitochondrial Parkinsonism A1 De la Casa-Fages, Beatriz A1 Fernández-Eulate, Gorka A1 Gamez, Josep A1 Barahona-Hernando, Raúl A1 Morís, Germán A1 García-Barcina, María A1 Infante, Jon A1 Zulaica, Miren A1 Fernández-Pelayo, Uxoa A1 Muñoz-Oreja, Mikel A1 Urtasun, Miguel A1 Olaskoaga, Ander A1 Zelaya, Victoria A1 Jericó, Ivonne A1 Saez-Villaverde, Raquel A1 Catalina, Irene A1 Sola Vendrell, Emma A1 Martínez-Sáez, Elena A1 Pujol, Aurora A1 Ruiz, Montserrat A1 Schlüter, Agatha A1 Spinazzola, Antonella A1 Muñoz-Blanco, Jose Luis A1 Holt, Ian A1 Álvarez, Victoria A1 López de Munaín, Adolfo A1 Grandas Pérez, Francisco Javier AB BackgroundPathogenic variants in the spastic paraplegia type 7 gene cause a complicated hereditary spastic paraplegia phenotype associated with classical features of mitochondrial diseases, including ataxia, progressive external ophthalmoplegia, and deletions of mitochondrial DNA.ObjectivesTo better characterize spastic paraplegia type 7 disease with a clinical, genetic, and functional analysis of a Spanish cohort of spastic paraplegia type 7 patients.MethodsGenetic analysis was performed in patients suspecting hereditary spastic paraplegia and in 1 patient with parkinsonism and Pisa syndrome, through next-generation sequencing, whole-exome sequencing, targeted Sanger sequencing, and multiplex ligation-dependent probe analysis, and blood mitochondrial DNA levels determined by quantitative polymerase chain reaction.ResultsThirty-five patients were found to carry homozygous or compound heterozygous pathogenic variants in the spastic paraplegia type 7 gene. Mean age at onset was 40 years (range, 12–63); 63% of spastic paraplegia type 7 patients were male, and three-quarters of all patients had at least one allele with the c.1529C>T (p.Ala510Val) mutation. Eighty percent of the cohort showed a complicated phenotype, combining ataxia and progressive external ophthalmoplegia (65% and 26%, respectively). Parkinsonism was observed in 21% of cases. Analysis of blood mitochondrial DNA indicated that both patients and carriers of spastic paraplegia type 7 pathogenic variants had markedly lower levels of mitochondrial DNA than control subjects (228 per haploid nuclear DNA vs. 176 vs. 573, respectively; P < 0.001).ConclusionsParkinsonism is a frequent finding in spastic paraplegia type 7 patients. Spastic paraplegia type 7 pathogenic variants impair mitochondrial DNA homeostasis irrespective of the number of mutant alleles, type of variant, and patient or carrier status. Thus, spastic paraplegia type 7 supports mitochondrial DNA maintenance, and variants in the gene may cause parkinsonism owing to mitochondrial DNA abnormalities. Moreover, mitochondrial DNA blood analysis could be a useful biomarker to detect at risk families. PB Wiley SN 1547-1561 YR 2019 FD 2019 LK https://hdl.handle.net/20.500.14352/100492 UL https://hdl.handle.net/20.500.14352/100492 LA eng NO De la Casa-Fages, B., Fernández-Eulate, G., Gamez, J., Barahona-Hernando, R., Morís, G., García-Barcina, M., Infante, J., Zulaica, M., Fernández-Pelayo, U., Muñoz-Oreja, M., Urtasun, M., Olaskoaga, A., Zelaya, V., Jericó, I., Saez-Villaverde, R., Catalina, I., Sola, E., Martínez-Sáez, E., Pujol, A., Ruiz, M., Schlüter, A., Spinazzola, A., Muñoz-Blanco, J.L., Grandas, F., Holt, I., Álvarez, V. and López de Munaín, A. (2019), Parkinsonism and spastic paraplegia type 7: Expanding the spectrum of mitochondrial Parkinsonism. Mov Disord, 34: 1547-1561. https://doi.org/10.1002/mds.27812 NO Hesperia Foundation NO Eusko Jaurlaritza DS Docta Complutense RD 20 abr 2025