title: Hidden mutations in Cornelia de Lange syndrome limitations of sanger sequencing in molecular diagnostics.
abstract: Cornelia de Lange syndrome (CdLS) is a well-characterized developmental disorder. The genetic cause of CdLS is a mutation in one of five associated genes (NIPBL, SMC1A, SMC3, RAD21, and HDAC8) accounting for about 70% of cases. To improve our current molecular diagnostic and to analyze some of CdLS candidate genes, we developed and established a gene panel approach. Because recent data indicate a high frequency of mosaic NIPBL mutations that were not detected by conventional sequencing approaches of blood DNA, we started to collect buccal mucosa (BM) samples of our patients that were negative for mutations in the known CdLS genes. Here, we report the identification of three mosaic NIPBL mutations by our high-coverage gene panel sequencing approach that were undetected by classical Sanger sequencing analysis of BM DNA. All mutations were confirmed by the use of highly sensitive SNaPshot fragment analysis using DNA from BM, urine, and fibroblast samples. In blood samples, we could not detect the respective mutation. Finally, in fibroblast samples from all three patients, Sanger sequencing could identify all the mutations. Thus, our study highlights the need for highly sensitive technologies in molecular diagnostic of CdLS to improve genetic diagnosis and counseling of patients and their families.
authors.affiliation: Sektion für Funktionelle Genetik am Institut für Humangenetik Lübeck, Universität zu Lübeck, Lübeck, Germany.
authors.forename: Diana
authors.initials: D
authors.lastname: Braunholz
authors.forename: Carolin
authors.initials: C
authors.lastname: Obieglo
authors.forename: Ilaria
authors.initials: I
authors.lastname: Parenti
authors.forename: Jelena
authors.initials: J
authors.lastname: Pozojevic
authors.forename: Juliane
authors.initials: J
authors.lastname: Eckhold
authors.forename: Benedikt
authors.initials: B
authors.lastname: Reiz
authors.forename: Ingrid
authors.initials: I
authors.lastname: Braenne
authors.forename: Kerstin S
authors.initials: KS
authors.lastname: Wendt
authors.forename: Erwan
authors.initials: E
authors.lastname: Watrin
authors.forename: Julia
authors.initials: J
authors.lastname: Vodopiutz
authors.forename: Harald
authors.initials: H
authors.lastname: Rieder
authors.forename: Gabriele
authors.initials: G
authors.lastname: Gillessen-Kaesbach
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Kaiser
mesh_terms: D018797:Cell Cycle Proteins; D002648:Child; D002675:Child, Preschool; D003635:De Lange Syndrome / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods*; D006801:Humans; D009154:Mutation; D011506:Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA / Q000379:methods*; D055815:Young Adult
chemical_list: D018797:Cell Cycle Proteins; C487465:NIPBL protein, human; D011506:Proteins
keywords: CdLS; NIPBL; cohesin; mosaic; panel sequencing