{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T22:19:31Z","timestamp":1782771571132,"version":"3.54.5"},"reference-count":47,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2022,8,8]],"date-time":"2022-08-08T00:00:00Z","timestamp":1659916800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background: Prader-Willi syndrome (PWS) is a rare genetic disorder resulting from the lack of expression of the PWS region (locus q11-q13) on the paternally derived chromosome 15, as a result of a type I or II paternal deletion (50%), maternal uniparental disomy (43%), imprinting defect (4%) or translocation (&lt;1%). In very rare cases, atypical deletions, smaller or larger than the typical deletion, are identified. These patients may have distinct phenotypical features and provide further information regarding the genotype\u2013phenotype correlation in PWS. Methods: A prospective study in eight patients (six males and two females) with an atypical deletion in the PWS region accompanies an overview of reported cases. Results: All patients had hypotonia (100%) and many had typical PWS facial characteristics (75%), social and emotional developmental delays (75%), intellectual disabilities (50%), neonatal feeding problems and tube feeding (63%), history of obesity (50%), hyperphagia (50%) and scoliosis (50%). All males had cryptorchidism. Two patients had two separate deletions in the PWS critical region. Conclusions: Our findings provide further insight into PWS genotype\u2013phenotype correlations; our results imply that inclusion of both SNURF-SNPRN and SNORD-116 genes in the deletion leads to a more complete PWS phenotype. A larger deletion, extending further upstream and downstream from these genes, does not cause a more severe phenotype. Conventional PWS methylation testing may miss small deletions, which can be identified using targeted next generation sequencing. PWS\u2019s phenotypic diversity might be caused by differentially methylated regions outside the 15q11.2 locus.<\/jats:p>","DOI":"10.3390\/jcm11154636","type":"journal-article","created":{"date-parts":[[2022,8,8]],"date-time":"2022-08-08T22:33:11Z","timestamp":1659997991000},"page":"4636","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Atypical 15q11.2-q13 Deletions and the Prader-Willi Phenotype"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2410-9978","authenticated-orcid":false,"given":"Lionne N.","family":"Grootjen","sequence":"first","affiliation":[{"name":"Dutch Reference Center for Prader-Willi Syndrome, 3015 CN Rotterdam, The Netherlands"},{"name":"Department of Pediatrics, Subdivision of Endocrinology, Erasmus University Medical Center-Sophia Children\u2019s Hospital, 3015 CN Rotterdam, The Netherlands"},{"name":"Dutch Growth Research Foundation, 3016 AH Rotterdam, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alicia F.","family":"Juriaans","sequence":"additional","affiliation":[{"name":"Dutch Reference Center for Prader-Willi Syndrome, 3015 CN Rotterdam, The Netherlands"},{"name":"Department of Pediatrics, Subdivision of Endocrinology, Erasmus University Medical Center-Sophia Children\u2019s Hospital, 3015 CN Rotterdam, The Netherlands"},{"name":"Dutch Growth Research Foundation, 3016 AH Rotterdam, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gerthe F.","family":"Kerkhof","sequence":"additional","affiliation":[{"name":"Dutch Reference Center for Prader-Willi Syndrome, 3015 CN Rotterdam, The Netherlands"},{"name":"Department of Pediatrics, Subdivision of Endocrinology, Erasmus University Medical Center-Sophia Children\u2019s Hospital, 3015 CN Rotterdam, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anita C. S.","family":"Hokken-Koelega","sequence":"additional","affiliation":[{"name":"Dutch Reference Center for Prader-Willi Syndrome, 3015 CN Rotterdam, The Netherlands"},{"name":"Department of Pediatrics, Subdivision of Endocrinology, Erasmus University Medical Center-Sophia Children\u2019s Hospital, 3015 CN Rotterdam, The Netherlands"},{"name":"Dutch Growth Research Foundation, 3016 AH Rotterdam, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1038\/gim.0b013e31822bead0","article-title":"Prader-Willi syndrome","volume":"14","author":"Cassidy","year":"2012","journal-title":"Genet. 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