Genetic heterogeneity in Cornelia de Lange syndrome (CdLS) and CdLS-like phenotypes with observed and predicted levels of mosaicism. Issue 10 (14th August 2014)

• Record Type: Journal Article
• Authors: Ansari, Morad; Poke, Gemma; Ferry, Quentin; Williamson, Kathleen; Aldridge, Roland; Meynert, Alison M; Bengani, Hemant; Chan, Cheng Yee; Kayserili, Hülya; Avci, Şahin; Hennekam, Raoul C M; Lampe, Anne K; Redeker, Egbert; Homfray, Tessa; Ross, Alison; Falkenberg Smeland, Marie; Mansour, Sahar; Parker, Michael J; Cook, Jacqueline A; Splitt, Miranda; Fisher, Richard B; Fryer, Alan; Magee, Alex C; Wilkie, Andrew; Barnicoat, Angela; Brady, Angela F; Cooper, Nicola S; Mercer, Catherine; Deshpande, Charu; Bennett, Christopher P; Pilz, Daniela T; Ruddy, Deborah; Cilliers, Deirdre; Johnson, Diana S; Josifova, Dragana; Rosser, Elisabeth; Thompson, Elizabeth M; Wakeling, Emma; Kinning, Esther; Stewart, Fiona; Flinter, Frances; Girisha, Katta M; Cox, Helen; Firth, Helen V; Kingston, Helen; Wee, Jamie S; Hurst, Jane A; Clayton-Smith, Jill; Tolmie, John; Vogt, Julie; Tatton–Brown, Katrina; Chandler, Kate; Prescott, Katrina; Wilson, Louise; Behnam, Mahdiyeh; McEntagart, Meriel; Davidson, Rosemarie; Lynch, Sally-Ann; Sisodiya, Sanjay; Mehta, Sarju G; McKee, Shane A; Mohammed, Shehla; Holden, Simon; Park, Soo-Mi; Holder, Susan E; Harrison, Victoria; McConnell, Vivienne; Lam, Wayne K; Green, Andrew J; Donnai, Dian; Bitner-Glindzicz, Maria; Donnelly, Deirdre E; Nellåker, Christoffer; Taylor, Martin S; FitzPatrick, David R;
• Is Part Of: Journal of medical genetics. Volume 51:Issue 10(2014)
• Page Start: 659
• Page End: 668
• Publication Date: 2014-08-14
• Subjects: Molecular genetics -- Copy-number -- Clinical genetics; Medical genetics -- Periodicals; 616.042
• DOI: 10.1136/jmedgenet-2014-102573
• Languages: English
• ISSNs: 1468-6244

Abstract

Abstract : Background: Cornelia de Lange syndrome (CdLS) is a multisystem disorder with distinctive facial appearance, intellectual disability and growth failure as prominent features. Most individuals with typical CdLS have de novo heterozygous loss-of-function mutations in NIPBL with mosaic individuals representing a significant proportion. Mutations in other cohesin components, SMC1A, SMC3, HDAC8 and RAD21 cause less typical CdLS. Methods: We screened 163 affected individuals for coding region mutations in the known genes, 90 for genomic rearrangements, 19 for deep intronic variants in NIPBL and 5 had whole-exome sequencing. Results: Pathogenic mutations [including mosaic changes] were identified in: NIPBL 46 [3] (28.2%); SMC1A 5 [1] (3.1%); SMC3 5 [1] (3.1%); HDAC8 6 [0] (3.6%) and RAD21 1 [0] (0.6%). One individual had a de novo 1.3 Mb deletion of 1p36.3. Another had a 520 kb duplication of 12q13.13 encompassing ESPL1, encoding separase, an enzyme that cleaves the cohesin ring. Three de novo mutations were identified in ANKRD11 demonstrating a phenotypic overlap with KBG syndrome. To estimate the number of undetected mosaic cases we used recursive partitioning to identify discriminating features in the NIPBL- positive subgroup. Filtering of the mutation-negative group on these features classified at least 18% as ' NIPBL- like'. A computer composition of the average face of this NIPBL -like subgroup was also more typical in appearance than that of all others in the mutation-negative group supporting the existence of undetected mosaic cases. Conclusions: Future diagnostic testing in 'mutation-negative' CdLS thus merits deeper sequencing of multiple DNA samples derived from different tissues.