{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T16:22:01Z","timestamp":1787761321294,"version":"build-2784847793"},"reference-count":22,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"1","license":[{"start":{"date-parts":[[2026,1,1]],"date-time":"2026-01-01T00:00:00Z","timestamp":1767225600000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2026,1]]},"abstract":"<jats:sec>\n                    <jats:title>Background and Objectives:<\/jats:title>\n                    <jats:p>\n                      Spinocerebellar ataxia type 2 (SCA2) is caused by cytosine-adenine-guanine (CAG) nucleotide repeat expansion in the\n                      <jats:italic toggle=\"yes\">ATXN2<\/jats:italic>\n                      gene. Mitochondrial DNA (mtDNA) haplogroups may have an influence on the disease presentation of SCA2.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>A total of 217 SCA2 patients were subjected to D-loop region sequencing for inferring mitochondrial haplogroups (mt-haplogroups). The association of age of onset (AO) and mt-haplogroup was assessed using the analysis of covariance (ANCOVA) method.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>\n                      The major haplogroups found in SCA2 patients were H (24.9%), L (6.5%), U (17.1%), W (1.8%), M (24.9%), G (0.5%), A (2.3%), N (6.0%), J (0.9%), I (1.4%), T (2.8%), R (3.2%), D (0.9%), C (0.5%), K (0.9%),\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      (3.2%), and S (2.3%). AO was significantly different at the same expanded CAG repeats in SCA2 patients, showing the role of other genetic factors in the AO modifiers. The ANCOVA model revealed a significant effect of mtDNA haplogroup on AO (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = 0.005), with variations in haplogroups adjusted for CAG repeat length. Post-hoc analyses further confirmed that haplogroup T (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = 0.004) and haplogroup M (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = 0.01) were significantly associated with AO compared to other haplogroups. Specifically, haplogroup M was linked to an early AO, while haplogroup T was associated with a late AO.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions:<\/jats:title>\n                    <jats:p>The study suggests an association between mt-halogroups and AO in SCA2, independent of CAG repeat length, with haplogroups T and M emerging as potential modifiers that may modulate disease progression. Further research is needed to explore the mechanisms behind these associations and validate the findings in larger cohorts.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.4103\/aian.aian_426_25","type":"journal-article","created":{"date-parts":[[2026,2,16]],"date-time":"2026-02-16T12:00:07Z","timestamp":1771243207000},"page":"21-27","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":0,"title":["Mitochondrial DNA Haplogroups and Age at Onset of Spinocerebellar Ataxia Type 2: A Study in Indian Patients"],"prefix":"10.4103","volume":"29","author":[{"given":"Akhilesh Kumar","family":"Sonakar","sequence":"first","affiliation":[{"name":"Department of Neurology, Neuroscience Centre, All India Institute of Medical Sciences, New Delhi, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chhavi","family":"Sharma","sequence":"additional","affiliation":[{"name":"Department of Neurology, Neuroscience Centre, All 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