{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,22]],"date-time":"2026-06-22T17:47:40Z","timestamp":1782150460413,"version":"3.54.5"},"reference-count":29,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"1","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>Introduction and Objective<\/jats:title>\n                    <jats:p>Complete monosomy 21 is a rare and lethal chromosomal disorder, with fewer than 50 cases reported. Its mosaic form is the only viable presentation, yet the full phenotypic spectrum remains poorly understood, prompting this work to expand clinical and cytogenetic insights.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We report the first genetically confirmed African case in a female infant referred for genetic testing because of distinctive dysmorphic features. Blood karyotype revealed 45,XX,-21[2]\/46,XX[28] mosaicism, and fluorescence in-situ hybridization showed 15 and 25% mosaicism in blood and buccal cells, respectively. A systematic literature review identified 23 previously reported cases, including nine isolated and 14 with additional chromosomal abnormalities.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The average maternal age was 27.5 years, unlike trisomy 21, where advanced maternal age is a major risk factor. Clinical manifestations include microcephaly, craniofacial dysmorphism, and congenital heart defects, with more severe phenotypes in complex cases. Hematological anomalies vary, with anemia in isolated and thrombocytopenia in complex cases. Notably, our patient displayed previously unreported peripheral hypothyroidism. The correlation between mosaicism levels and clinical severity remains unclear, highlighting the need for multi-tissue analyses.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>TThis study expands current knowledge of mosaic monosomy 21 and emphasizes the value of detailed cytogenetic assessment and phenotypic characterization to better define its clinical spectrum.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1097\/mcd.0000000000000545","type":"journal-article","created":{"date-parts":[[2025,11,7]],"date-time":"2025-11-07T02:03:44Z","timestamp":1762481024000},"page":"15-27","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":0,"title":["A rare case of mosaic monosomy 21 in a Moroccan patient: clinical findings and insights from a systematic review"],"prefix":"10.1097","volume":"35","author":[{"given":"Amal","family":"Ouskri","sequence":"first","affiliation":[{"name":"Hassan II University Hospital, Fez"},{"name":"Sidi Mohamed Ben Abdellah University, Fez"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abdelhamid","family":"Bouramtane","sequence":"additional","affiliation":[{"name":"Hassan II University Hospital, Fez"},{"name":"Sidi Mohamed Ben Abdellah University, Fez"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rania","family":"Bouchikhi","sequence":"additional","affiliation":[{"name":"Hassan II University Hospital, Fez"},{"name":"Sidi Mohamed Ben Abdellah University, Fez"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yasser Ali","family":"El Asri","sequence":"additional","affiliation":[{"name":"Hassan II University Hospital, Fez"},{"name":"Sidi Mohamed Ben Abdellah University, Fez"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Saadia","family":"Amasdl","sequence":"additional","affiliation":[{"name":"Hassan II University Hospital, Fez"},{"name":"Sidi Mohamed Ben Abdellah University, Fez"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Laila","family":"Smaili","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Pagnon Hospital, Meknes, Morocco"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Laila","family":"Bouguenouch","sequence":"additional","affiliation":[{"name":"Hassan II University Hospital, Fez"},{"name":"Sidi Mohamed Ben Abdellah University, Fez"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karim","family":"Ouldim","sequence":"additional","affiliation":[{"name":"Hassan II University Hospital, Fez"},{"name":"Sidi Mohamed Ben Abdellah University, Fez"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2025,9,25]]},"reference":[{"key":"R1-20260622","doi-asserted-by":"crossref","first-page":"279","DOI":"10.1002\/ajmg.1320040311","article-title":"Monosomy 21: a possible stepwise evolution of the karyotype.","volume":"4","author":"Abeliovich","year":"1979","journal-title":"Am J Med Genet"},{"key":"R2-20260622","doi-asserted-by":"crossref","first-page":"501","DOI":"10.1002\/(SICI)1096-8628(19960823)64:3<501::AID-AJMG11>3.0.CO;2-P","article-title":"Deletion of chromosome 21 in a girl with congenital hypothyroidism and mild mental retardation.","volume":"64","author":"Ahlbom","year":"1996","journal-title":"Am J Med Genet"},{"key":"R3-20260622","first-page":"265","article-title":"Linkage analysis excludes familial congenital hypothyroidism from chromosome 21.","volume":"9","author":"Ahlbom","year":"1998","journal-title":"Genet Couns"},{"key":"R4-20260622","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1186\/s13039-020-00513-2","article-title":"De novo mosaic and partial monosomy of chromosome 21 in a case with superior vena cava duplication.","volume":"13","author":"Azad","year":"2020","journal-title":"Mol. 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