{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,14]],"date-time":"2026-01-14T18:32:51Z","timestamp":1768415571714,"version":"3.49.0"},"reference-count":45,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2022,4,23]],"date-time":"2022-04-23T00:00:00Z","timestamp":1650672000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004329","name":"Slovenian Research Agency","doi-asserted-by":"publisher","award":["P3-0343"],"award-info":[{"award-number":["P3-0343"]}],"id":[{"id":"10.13039\/501100004329","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Genes"],"abstract":"<jats:p>Klinefelter syndrome is the most commonly reported sex chromosome abnormality. It is heavily underdiagnosed due to the substantial variability of clinical presentations but is generally characterized by small, firm testes, hypergonadotropic hypogonadism, and the absence of spermatogenesis. Most patients with Klinefelter syndrome have a 47,XXY genotype. If they present with mosaicism, two different cell lines are usually identified, an aneuploid 47,XXY cell line and a normal male 46,XY cell line. There are very few cases of 47,XXY mosaicism with the additional female cell line 46,XX described in the literature. We report a case of an adolescent with the male phenotype and a rare variant mosaic 47,XXY\/46,XX karyotype who presented with painless bilateral gynaecomastia. 47,XXY and 46,XX mosaic cell lines were identified with GTG-banding and further characterized using fluorescent in situ hybridization. We summarized the available clinical presentations of reported male patients with 47,XXY\/46,XX mosaicism. To improve the clinical management and quality of life in individuals with rare and cryptic genomic imbalances, the genetic diagnosis would need to be extended to atypical cases.<\/jats:p>","DOI":"10.3390\/genes13050744","type":"journal-article","created":{"date-parts":[[2022,4,23]],"date-time":"2022-04-23T08:14:06Z","timestamp":1650701646000},"page":"744","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["An Adolescent Boy with Klinefelter Syndrome and 47,XXY\/46,XX Mosaicism: Case Report and Review of Literature"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5330-3983","authenticated-orcid":false,"given":"Tinka","family":"Hovnik","sequence":"first","affiliation":[{"name":"Clinical Institute for Special Laboratory Diagnostics, University Children\u2019s Hospital, UMC, 1000 Ljubljana, Slovenia"},{"name":"Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eva","family":"Zitnik","sequence":"additional","affiliation":[{"name":"Department of Pediatric Endocrinology, Diabetes and Metabolic Diseases, University Children\u2019s Hospital, UMC, 1000 Ljubljana, Slovenia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0836-5114","authenticated-orcid":false,"given":"Magdalena","family":"Avbelj Stefanija","sequence":"additional","affiliation":[{"name":"Department of Pediatric Endocrinology, Diabetes and Metabolic Diseases, University Children\u2019s Hospital, UMC, 1000 Ljubljana, Slovenia"},{"name":"Department of Pediatrics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sara","family":"Bertok","sequence":"additional","affiliation":[{"name":"Department of Pediatric Endocrinology, Diabetes and Metabolic Diseases, University Children\u2019s Hospital, UMC, 1000 Ljubljana, Slovenia"},{"name":"Department of Pediatrics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Katarina","family":"Sedej","sequence":"additional","affiliation":[{"name":"Department of Pediatric Endocrinology, Diabetes and Metabolic Diseases, University Children\u2019s Hospital, UMC, 1000 Ljubljana, Slovenia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Vesna","family":"Bancic Silva","sequence":"additional","affiliation":[{"name":"Department of Pediatric Endocrinology, Diabetes and Metabolic Diseases, University Children\u2019s Hospital, UMC, 1000 Ljubljana, Slovenia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0273-4732","authenticated-orcid":false,"given":"Tadej","family":"Battelino","sequence":"additional","affiliation":[{"name":"Department of Pediatric Endocrinology, Diabetes and Metabolic Diseases, University Children\u2019s Hospital, UMC, 1000 Ljubljana, Slovenia"},{"name":"Department of Pediatrics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5246-9869","authenticated-orcid":false,"given":"Urh","family":"Groselj","sequence":"additional","affiliation":[{"name":"Department of Pediatric Endocrinology, Diabetes and Metabolic Diseases, University Children\u2019s Hospital, UMC, 1000 Ljubljana, Slovenia"},{"name":"Department of Pediatrics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,23]]},"reference":[{"key":"ref_1","first-page":"209","article-title":"Sex chromosome abnormalities found among 34,910 newborn children: Results from a 13-year incidence study in Arhus, Denmark","volume":"26","author":"Nielsen","year":"1990","journal-title":"Birth Defects Orig. 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