{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,6]],"date-time":"2026-01-06T18:24:46Z","timestamp":1767723886073,"version":"3.48.0"},"reference-count":13,"publisher":"BMJ","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["Pract Neurol"],"accepted":{"date-parts":[[2025,12,19]]},"abstract":"<jats:p>\n                    Opticospinal syndrome (concurrent involvement of the optic nerve and spinal cord) in young adults is usually caused by an immune-mediated disease, such as multiple sclerosis, neuromyelitis optica spectrum disorder or myelin oligodendrocyte glycoprotein antibody-associated disease. These conditions typically respond to corticosteroids and follow a relapsing-remitting course. We report a man with opticospinal syndrome, who initially appeared steroid-responsive, but was subsequently found to have a pathogenic mutation in the methylenetetrahydrofolate reductase (\n                    <jats:italic>MTHFR<\/jats:italic>\n                    ) gene, causing folate deficiency and associated neurological complications. Skin hyperpigmentation had suggested a metabolic cause, such as adrenoleukodystrophy or a disorder of cobalamin metabolism. Importantly, steroid responsiveness alone is not diagnostic for inflammatory and demyelinating disorders.\n                  <\/jats:p>","DOI":"10.1136\/pn-2025-004704","type":"journal-article","created":{"date-parts":[[2026,1,6]],"date-time":"2026-01-06T18:20:38Z","timestamp":1767723638000},"page":"pn-2025-004704","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Folate metabolism disorder presenting as an opticospinal syndrome"],"prefix":"10.1136","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-1054-2836","authenticated-orcid":false,"given":"Sidharth Rao","family":"Errabelly","sequence":"first","affiliation":[{"name":"All India Institute of Medical Sciences, New Delhi, Delhi, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eeshaan","family":"Agrawal","sequence":"additional","affiliation":[{"name":"All India Institute of Medical Sciences, New Delhi, Delhi, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0418-0152","authenticated-orcid":false,"given":"Prachi","family":"Mohapatra","sequence":"additional","affiliation":[{"name":"Department of Neurology, All India Institute of Medical Sciences, New Delhi, Delhi, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ajay","family":"Garg","sequence":"additional","affiliation":[{"name":"Department of Neuroimaging and Interventional Neuroradiology, All India Institute of Medical Sciences, New Delhi, Delhi, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0128-7037","authenticated-orcid":false,"given":"Arunmozhimaran","family":"Elavarasi","sequence":"additional","affiliation":[{"name":"Department of Neurology, All India Institute of Medical Sciences, New Delhi, Delhi, India"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2026,1,6]]},"reference":[{"key":"2026010610202463000_pn-2025-004704v1.1","doi-asserted-by":"publisher","DOI":"10.1136\/jnnp-2014-308984"},{"key":"2026010610202463000_pn-2025-004704v1.2","doi-asserted-by":"publisher","DOI":"10.1016\/s1474-4422(21)00218-0"},{"key":"2026010610202463000_pn-2025-004704v1.3","doi-asserted-by":"publisher","DOI":"10.3988\/jcn.2014.10.4.281"},{"key":"2026010610202463000_pn-2025-004704v1.4","doi-asserted-by":"publisher","DOI":"10.1007\/s10545-016-9991-4"},{"key":"2026010610202463000_pn-2025-004704v1.5","doi-asserted-by":"crossref","unstructured":"Aliyar A , Endrakanti M , Singh RK , et al . Late-onset cobalamin C disease: rare but treatable. Pract Neurol 2022. doi:10.1136\/practneurol-2022-003447","DOI":"10.1136\/practneurol-2022-003447"},{"key":"2026010610202463000_pn-2025-004704v1.6","doi-asserted-by":"publisher","DOI":"10.1136\/jnnp-2018-319481"},{"key":"2026010610202463000_pn-2025-004704v1.7","first-page":"1363","article-title":"Severe hyperhomocysteinemia due to MTHFR deficiency caused by a new mutation: A case report and literature review","volume":"49","author":"Yin","year":"2024","journal-title":"Zhong Nan Da Xue Xue Bao Yi Xue Ban"},{"key":"2026010610202463000_pn-2025-004704v1.8","doi-asserted-by":"crossref","first-page":"2206","DOI":"10.1007\/s00415-021-10841-x","article-title":"Phoenix from the ashes: dramatic improvement in severe late-onset methylenetetrahydrofolate reductase (MTHFR) deficiency with a complete loss of vision","volume":"269","author":"Biesalski","year":"2022","journal-title":"J Neurol"},{"key":"2026010610202463000_pn-2025-004704v1.9","doi-asserted-by":"crossref","first-page":"33","DOI":"10.4103\/IJO.IJO_910_24","article-title":"Vision loss as an initial clinical manifestation in a case of adolescent-onset MTHFR enzyme deficiency with a rare genetic mutation","volume":"5","author":"Jha","year":"2025","journal-title":"J Ophthalmol Case Rep"},{"key":"2026010610202463000_pn-2025-004704v1.10","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1007\/s10545-015-9860-6","article-title":"Clinical pattern, mutations and in vitro residual activity in 33 patients with severe 5, 10 methylenetetrahydrofolate reductase (MTHFR) deficiency","volume":"39","author":"Huemer","year":"2016","journal-title":"J Inherit Metab Dis"},{"key":"2026010610202463000_pn-2025-004704v1.11","first-page":"1688","article-title":"Acute methotrexate neurotoxicity: findings on diffusion-weighted imaging and correlation with clinical outcome","volume":"25","author":"Rollins","year":"2004","journal-title":"AJNR Am J Neuroradiol"},{"key":"2026010610202463000_pn-2025-004704v1.12","doi-asserted-by":"crossref","first-page":"28","DOI":"10.4103\/CRST.CRST_22_19","article-title":"Clinical\u2013radiological features of methotrexate-induced subacute leukoencephalopathy in patients with acute lymphoblastic leukemia: \u201cPanda eye sign\u201d on diffusion weighted-magnetic resonance imaging","volume":"2","author":"Mahajan","year":"2019","journal-title":"Cancer Res Stat Treat"},{"key":"2026010610202463000_pn-2025-004704v1.13","doi-asserted-by":"crossref","first-page":"188","DOI":"10.1001\/jamaneurol.2013.4915","article-title":"Survival and psychomotor development with early betaine treatment in patients with severe methylenetetrahydrofolate reductase deficiency","volume":"71","author":"Diekman","year":"2014","journal-title":"JAMA Neurol"}],"container-title":["Practical Neurology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/pn-2025-004704","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,6]],"date-time":"2026-01-06T18:20:40Z","timestamp":1767723640000},"score":1,"resource":{"primary":{"URL":"https:\/\/pn.bmj.com\/lookup\/doi\/10.1136\/pn-2025-004704"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,6]]},"references-count":13,"alternative-id":["10.1136\/pn-2025-004704"],"URL":"https:\/\/doi.org\/10.1136\/pn-2025-004704","relation":{},"ISSN":["1474-7758","1474-7766"],"issn-type":[{"value":"1474-7758","type":"print"},{"value":"1474-7766","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,6]]}}}