@article{HofrichterDollHabibietal.2019,
  author    = {Hofrichter, Michaela A. H. and Doll, Julia and Habibi, Haleh and Enayati, Samaneh and Mehrjardi, Mohammad Yahya Vahidi and M{\"u}ller, Tobias and Dittrich, Marcus and Haaf, Thomas and Vona, Barbara},
  title     = {Exome-wide copy number variation analysis identifies a COL9A1 in frame deletion that is associated with hearing loss},
  series = {European Journal of Medical Genetics},
  volume    = {62},
  journal   = {European Journal of Medical Genetics},
  doi       = {10.1016/j.ejmg.2019.103724},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-322008},
  year      = {2019},
  abstract  = {Pathogenic variants in COL9A1 are primarily associated with autosomal recessive Stickler syndrome. Patients with COL9A1-associated Stickler syndrome (STL) present hearing loss (HL), ophthalmic manifestations and skeletal abnormalities. However, the clinical spectrum of patients with COL9A1 variants can also include multiple epiphyseal dysplasia, as well as non-syndromic HL that was observed in one previously reported proband. Exome sequencing was performed on the genomic DNA of an Iranian patient and his affected brother who both report non-syndromic HL. A 44.6 kb homozygous in-frame deletion spanning exons 6 to 33 of COL9A1 was detected via exome-based copy number variation analysis. The deleted exons were confirmed by PCR in the patient and his affected brother, who both have non-syndromic HL. Segregation analysis via qPCR confirmed the parents as heterozygous deletion carriers. Breakpoint analysis mapped the homozygous deletion spanning introns 5 to 33 (g.70,948,188_70,997,277del, NM_001851.4(COL9A1):c.697-3754_2112+769del, p.(Phe233_Ser704del), with an additional 67 bp of inserted intronic sequence that may have originated due to a fork stalling and template switching/microhomology-mediated break-induced replication (FoSTeS/MMBIR) mechanism. This mechanism has not been previously implicated in HL or STL. This is also the first reported copy number variation in COL9A1 that was identified through an exome data set in an Iranian family with apparent non-syndromic HL. The present study emphasizes the importance of exome-wide copy number variation analysis in molecular diagnosis and provides supporting evidence to associate COL9A1 with autosomal recessive non-syndromic HL.},
  language  = {en}
}
@article{LekszasNandaVonaetal.2019,
  author    = {Lekszas, Caroline and Nanda, Indrajit and Vona, Barbara and B{\"o}ck, Julia and Ashrafzadeh, Farah and Donyadideh, Nahid and Ebrahimzadeh, Farnoosh and Ahangari, Najmeh and Maroofian, Reza and Karimiani, Ehsan Ghayoor and Haaf, Thomas},
  title     = {Unbalanced segregation of a paternal t(9;11)(p24.3;p15.4) translocation causing familial Beckwith-Wiedemann syndrome: a case report},
  series = {BMC Medical Genomics},
  volume    = {12},
  journal   = {BMC Medical Genomics},
  doi       = {10.1186/s12920-019-0539-y},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200422},
  pages     = {83},
  year      = {2019},
  abstract  = {Background The vast majority of cases with Beckwith-Wiedemann syndrome (BWS) are caused by a molecular defect in the imprinted chromosome region 11p15.5. The underlying mechanisms include epimutations, uniparental disomy, copy number variations, and structural rearrangements. In addition, maternal loss-of-function mutations in CDKN1C are found. Despite growing knowledge on BWS pathogenesis, up to 20\% of patients with BWS phenotype remain without molecular diagnosis. Case presentation Herein, we report an Iranian family with two females affected with BWS in different generations. Bisulfite pyrosequencing revealed hypermethylation of the H19/IGF2: intergenic differentially methylated region (IG DMR), also known as imprinting center 1 (IC1) and hypomethylation of the KCNQ1OT1: transcriptional start site (TSS) DMR (IC2). Array CGH demonstrated an 8 Mb duplication on chromosome 11p15.5p15.4 (205,827-8,150,933) and a 1 Mb deletion on chromosome 9p24.3 (209,020-1,288,114). Chromosome painting revealed that this duplication-deficiency in both patients is due to unbalanced segregation of a paternal reciprocal t(9;11)(p24.3;p15.4) translocation. Conclusions This is the first report of a paternally inherited unbalanced translocation between the chromosome 9 and 11 short arms underlying familial BWS. Copy number variations involving the 11p15.5 region are detected by the consensus diagnostic algorithm. However, in complex cases which do not only affect the BWS region itself, characterization of submicroscopic chromosome rearrangements can assist to estimate the recurrence risk and possible phenotypic outcomes.},
  language  = {en}
}