Study Of TGFBI Gene Mutations In The Patients With Two Types Of Corneal Dystrophy In Northeast In China

Background:Corneal dystrophy refer to a group of primary, inherted, bilateral corneal diseases with pathological change. There are different form deposits in the corneal tissue. Prior to 1997, diagnosis of corneal dystrophy rely on the clinical features and pathological features. However, for many atypical cases often are difficult to diagnosis, even after a stereomicroscope, causing difficulty classify or misdiagnosed.with the development of molecular biology study, corneal dystrophy genetic research and gene therapy has become the hotspot. Currently, the chromosomes are associated with corneal dystrophy include: 1,5,9,10,12,16,17,20,21 and the X chromosome; corneal dystrophy gene has been identified include :TGFBI ( TGFBI) CHST6, K3, K12, M1SI, GSN and so on. TGFBI gene mutations lead to the most common corneal dystrophy, The gene mutation would lead to different sites in different clinical phenotypes of corneal dystrophy. For the common lattice corneal dystrophy (Lattice corneal dystrophy. CDL) and Avellino corneal dystrophy (Avellino corneal dystr ophy, CDA). At present, there are few research in China and the northeastern region has not this kind of research.Objective:To identify mutations in the TGFBI gene in the patients with lattice corneal dystrophy (CDL) or Avellino corneal dystrophy (CDA) in the Northeast of China ,to investigate the relation of the genotype and the clinical type.Methods:Molecular genetic analysis was performed on DNA extracted from periphera leukocytes from fifteen patients with corneal dystrophy in He Eye Hospital from July 2005 to July 2006. Including 6patiens with Lattice corneal dystrophy (CDLⅠ)and 9 Avellino corneal dystrophy(CDA). Exons4,12,14of the TGFBI gene were amplified by polymerase chain reaction and were sequenced directly. The cornea of these patients were examined with slit-lamp biomicroscope and photographed. At the same time,30 normal subjects were recruited in the molecular genetic analysis as the controls.Results: Mutations in TGFBI gene were detected in all the patients with corneal dystrophies. TGFBI gene mutations were not found in normal subjects.6 CDLⅠpatients had R124C mutation (one missense mutation at position 417C→G of exon4) in the TGFBI gene, 9 Avellino patients had R124H mutation (one missense mutation at position 418G→A of exon4) in the TGFBI gene all of them were heterozygous.Conclusion: R124C and R124H mutations in TGFBI gene were found in the patients with lattic and Avellino corneal dystrophies.Condons 124 may be the hot spots for the mutations in the TGFBI gene in the Northeast of Chinese patients with corneal dystrophies.