title: Expanding the clinical spectrum of COL1A1 mutations in different forms of glaucoma.
abstract: Primary congenital glaucoma (PCG) and early onset glaucomas are one of the major causes of children and young adult blindness worldwide. Both autosomal recessive and dominant inheritance have been described with involvement of several genes including CYP1B1, FOXC1, PITX2, MYOC and PAX6. However, mutations in these genes explain only a small fraction of cases suggesting the presence of further candidate genes.
  
  
  
  To elucidate further genetic causes of these conditions whole exome sequencing (WES) was performed in an Italian patient, diagnosed with PCG and retinal detachment, and his unaffected parents. Sanger sequencing of the complete coding region of COL1A1 was performed in a total of 26 further patients diagnosed with PCG or early onset glaucoma. Exclusion of pathogenic variations in known glaucoma genes as CYP1B1, MYOC, FOXC1, PITX2 and PAX6 was additionally done per Sanger sequencing and Multiple Ligation-dependent Probe Amplification (MLPA) analysis.
  
  
  
  In the patient diagnosed with PCG and retinal detachment, analysis of WES data identified compound heterozygous variants in COL1A1 (p.Met264Leu; p.Ala1083Thr). Targeted COL1A1 screening of 26 additional patients detected three further heterozygous variants (p.Arg253*, p.Gly767Ser and p.Gly154Val) in three distinct subjects: two of them diagnosed with early onset glaucoma and mild form of osteogenesis imperfecta (OI), one patient with a diagnosis of PCG at age 4 years. All five variants affected evolutionary, highly conserved amino acids indicating important functional restrictions. Molecular modeling predicted that the heterozygous variants are dominant in effect and affect protein stability and thus the amount of available protein, while the compound heterozygous variants act as recessive alleles and impair binding affinity to two main COL1A1 binding proteins: Hsp47 and fibronectin.
  
  
  
  Dominant inherited mutations in COL1A1 are known causes of connective tissues disorders such as OI. These disorders are also associated with different ocular abnormalities, although recognition of the common pathology for both features is seldom being recognized. Our results expand the role of COL1A1 mutations in different forms of early-onset glaucoma with and without signs of OI. Thus, we suggest including COL1A1 mutation screening in the genetic work-up of glaucoma cases and detailed ophthalmic examinations with fundus analysis in patients with OI.
authors.affiliation: Medical Genetics, A.O. Niguarda Ca'Granda Hospital, Milan, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Mauri
authors.affiliation: Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Uebe
authors.affiliation: Bioinformatics, Institute of Biochemistry, FAU Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Sticht
authors.affiliation: Augenklinik und Poliklinik, Joahnnes Gutenberg-Universität Mainz, Mainz, Germany.
authors.forename: Urs
authors.initials: U
authors.lastname: Vossmerbaeumer
authors.affiliation: Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Weisschuh
authors.affiliation: Medical Genetics, A.O. Niguarda Ca'Granda Hospital, Milan, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Manfredini
authors.affiliation: Clinica Zucchi, Monza, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Maselli
authors.affiliation: Medical Genetics, A.O. Niguarda Ca'Granda Hospital, Milan, Italy.
authors.forename: Mariacristina
authors.initials: M
authors.lastname: Patrosso
authors.affiliation: Shiley Eye Institute, UC San Diego, San Diego, CA, USA.
authors.forename: Robert N
authors.initials: RN
authors.lastname: Weinreb
authors.affiliation: Medical Genetics, A.O. Niguarda Ca'Granda Hospital, Milan, Italy.
authors.forename: Silvana
authors.initials: S
authors.lastname: Penco
authors.affiliation: Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Reis
authors.affiliation: Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany. francesca.pasutto@uk-erlangen.de.
authors.forename: Francesca
authors.identifier: 0000-0002-0026-5362
authors.initials: F
authors.lastname: Pasutto
mesh_terms: D000293:Adolescent; D024042:Collagen Type I / Q000235:genetics*; D000090602:Collagen Type I, alpha 1 Chain; D065633:Cytochrome P-450 CYP1B1 / Q000235:genetics; D003598:Cytoskeletal Proteins / Q000235:genetics; D059472:Exome / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics; D051858:Forkhead Transcription Factors / Q000235:genetics; D005901:Glaucoma / Q000235:genetics*; D006023:Glycoproteins / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics*; D010013:Osteogenesis Imperfecta / Q000235:genetics; D000071841:PAX6 Transcription Factor / Q000235:genetics; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics; D000097577:Homeobox Protein PITX2; D000099179:Myocilin
chemical_list: D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D065633:Cytochrome P-450 CYP1B1; D003598:Cytoskeletal Proteins; D005136:Eye Proteins; D051858:Forkhead Transcription Factors; D006023:Glycoproteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D014157:Transcription Factors; D000097577:Homeobox Protein PITX2; D000099179:Myocilin; C112743:FOXC1 protein, human; C000605730:PAX6 protein, human; C585496:CYP1B1 protein, human
keywords: COL1A1; Congenital glaucoma; Early onset glaucoma; Osteogenesis imperfecta; Whole exome sequencing