{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T20:44:40Z","timestamp":1789764280109,"version":"4.0.1"},"reference-count":41,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2021,2,8]],"date-time":"2021-02-08T00:00:00Z","timestamp":1612742400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003196","name":"Ministero della Salute","doi-asserted-by":"publisher","award":["RF-2016-02364123"],"award-info":[{"award-number":["RF-2016-02364123"]}],"id":[{"id":"10.13039\/501100003196","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The expanded CAG repeat number in HTT gene causes Huntington disease (HD), which is a severe, dominant neurodegenerative illness. The accurate determination of the expanded allele size is crucial to confirm the genetic status in symptomatic and presymptomatic at-risk subjects and avoid genetic polymorphism-related false-negative diagnoses. Precise CAG repeat number determination is critical to discriminate the cutoff between unexpanded and intermediate mutable alleles (IAs, 27\u201335 CAG) as well as between IAs and pathological, low-penetrance alleles (i.e., 36\u201339 CAG repeats), and it is also critical to detect large repeat expansions causing pediatric HD variants. We analyzed the HTT-CAG repeat number of 14 DNA reference materials and of a DNA collection of 43 additional samples carrying unexpanded, IAs, low and complete penetrance alleles, including large (&gt;60 repeats) and very large (&gt;100 repeats) expansions using a novel triplet-primed PCR-based assay, the AmplideX PCR\/CE HTT Kit. The results demonstrate that the method accurately genotypes both normal and expanded HTT-CAG repeat numbers and reveals previously undisclosed and very large CAG expansions &gt;200 repeats. We also show that this technique can improve genetic test reliability and accuracy by detecting CAG expansions in samples with sequence variations within or adjacent to the repeat tract that cause allele drop-outs or inaccuracies using other PCR methods.<\/jats:p>","DOI":"10.3390\/ijms22041689","type":"journal-article","created":{"date-parts":[[2021,2,9]],"date-time":"2021-02-09T23:43:16Z","timestamp":1612914196000},"page":"1689","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["A Novel Triplet-Primed PCR Assay to Detect the Full Range of Trinucleotide CAG Repeats in the Huntingtin Gene (HTT)"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4408-8062","authenticated-orcid":false,"given":"Alessandro","family":"De Luca","sequence":"first","affiliation":[{"name":"Medical Genetics Division, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Annunziata","family":"Morella","sequence":"additional","affiliation":[{"name":"Medical Genetics Division, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Federica","family":"Consoli","sequence":"additional","affiliation":[{"name":"Medical Genetics Division, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5832-8381","authenticated-orcid":false,"given":"Sergio","family":"Fanelli","sequence":"additional","affiliation":[{"name":"Huntington and Rare Diseases Unit, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Julie R.","family":"Thibert","sequence":"additional","affiliation":[{"name":"Asuragen, Inc., Austin, TX 78744, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarah","family":"Statt","sequence":"additional","affiliation":[{"name":"Asuragen, Inc., Austin, TX 78744, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9263-3475","authenticated-orcid":false,"given":"Gary J.","family":"Latham","sequence":"additional","affiliation":[{"name":"Asuragen, Inc., Austin, TX 78744, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7397-1727","authenticated-orcid":false,"given":"Ferdinando","family":"Squitieri","sequence":"additional","affiliation":[{"name":"Huntington and Rare Diseases Unit, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"The Huntington\u2019s Disease Collaborative Research Group (1993). 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