{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,26]],"date-time":"2026-10-26T16:04:22Z","timestamp":1793030662083,"version":"4.5.0"},"reference-count":96,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2023,5,24]],"date-time":"2023-05-24T00:00:00Z","timestamp":1684886400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The diagnosis and management of fragile X syndrome (FXS) have significantly improved in the last three decades, although the current diagnostic techniques are not yet able to precisely identify the number of repeats, methylation status, level of mosaicism, and\/or the presence of AGG interruptions. A high number of repeats (&gt;200) in the fragile X messenger ribonucleoprotein 1 gene (FMR1) results in hypermethylation of promoter and gene silencing. The actual molecular diagnosis is performed using a Southern blot, TP-PCR (Triplet-Repeat PCR), MS-PCR (Methylation-Specific PCR), and MS-MLPA (Methylation-Specific MLPA) with some limitations, with multiple assays being necessary to completely characterise a patient with FXS. The actual gold standard diagnosis uses Southern blot; however, it cannot accurately characterise all cases. Optical genome mapping is a new technology that has also been developed to approach the diagnosis of fragile X syndrome. Long-range sequencing represented by PacBio and Oxford Nanopore has the potential to replace the actual diagnosis and offers a complete characterization of molecular profiles in a single test. The new technologies have improved the diagnosis of fragile X syndrome and revealed unknown aberrations, but they are a long way from being used routinely in clinical practice.<\/jats:p>","DOI":"10.3390\/ijms24119206","type":"journal-article","created":{"date-parts":[[2023,5,25]],"date-time":"2023-05-25T02:58:48Z","timestamp":1684983528000},"page":"9206","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["Narrative Review: Update on the Molecular Diagnosis of Fragile X Syndrome"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-9885-642X","authenticated-orcid":false,"given":"Cristian-Gabriel","family":"Ciobanu","sequence":"first","affiliation":[{"name":"Medical Genetics Department, Faculty of Medicine, \u201cGrigore T. Popa\u201d University of Medicine and Pharmacy, University Street No 16, 700115 Iasi, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7518-4049","authenticated-orcid":false,"given":"Irina","family":"Nuc\u0103","sequence":"additional","affiliation":[{"name":"Medical Genetics Department, Faculty of Medicine, \u201cGrigore T. Popa\u201d University of Medicine and Pharmacy, University Street No 16, 700115 Iasi, Romania"},{"name":"Investigatii Medicale Praxis, St. Moara de Vant No 35, 700376 Iasi, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2183-0690","authenticated-orcid":false,"given":"Roxana","family":"Popescu","sequence":"additional","affiliation":[{"name":"Medical Genetics Department, Faculty of Medicine, \u201cGrigore T. Popa\u201d University of Medicine and Pharmacy, University Street No 16, 700115 Iasi, Romania"},{"name":"Medical Genetics Department, \u201cSaint Mary\u201d Emergency Children\u2019s Hospital, St. Vasile Lupu No 62, 700309 Iasi, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lucian-Mihai","family":"Antoci","sequence":"additional","affiliation":[{"name":"Medical Genetics Department, Faculty of Medicine, \u201cGrigore T. Popa\u201d University of Medicine and Pharmacy, University Street No 16, 700115 Iasi, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lavinia","family":"Caba","sequence":"additional","affiliation":[{"name":"Medical Genetics Department, Faculty of Medicine, \u201cGrigore T. 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Popa\u201d University of Medicine and Pharmacy, University Street No 16, 700115 Iasi, Romania"},{"name":"Medical Genetics Department, \u201cSaint Mary\u201d Emergency Children\u2019s Hospital, St. Vasile Lupu No 62, 700309 Iasi, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cosmin-Teodor","family":"Mihai","sequence":"additional","affiliation":[{"name":"Investigatii Medicale Praxis, St. Moara de Vant No 35, 700376 Iasi, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6762-4067","authenticated-orcid":false,"given":"Monica-Cristina","family":"P\u00e2nzaru","sequence":"additional","affiliation":[{"name":"Medical Genetics Department, Faculty of Medicine, \u201cGrigore T. Popa\u201d University of Medicine and Pharmacy, University Street No 16, 700115 Iasi, Romania"},{"name":"Medical Genetics Department, \u201cSaint Mary\u201d Emergency Children\u2019s Hospital, St. Vasile Lupu No 62, 700309 Iasi, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,5,24]]},"reference":[{"key":"ref_1","unstructured":"Stone, W.L., Basit, H., Shah, M., and Los, E. (2023). 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