PURPOSE: Congenital stationary night blindness (CSNB) is a group of nonprogressive retinal disorders characterized by impaired night vision that occurs in autosomal dominant, autosomal recessive, or X-linked forms. Autosomal recessive (ar)CSNB seems to be very rare. Mice lacking the metabotropic glutamate receptor 6 (Grm6) have a defect in signal transmission from the photoreceptors to ON-bipolar cells. In the current study, the human orthologue (GRM6) was screened as a likely candidate for arCSNB. METHODS: arCSNB individuals of five families were screened for mutations in GRM6. Subsequently, they were examined with standard and 15-Hz flicker electroretinography (ERG). These recordings were compared with those of patients with X-linked CSNB1. RESULTS: Affected individuals in three of five families carried either compound heterozygous or homozygous mutations in GRM6. Strikingly, all of them displayed a distinctive abnormality of the rod pathway signals on scotopic 15-Hz flicker ERG. CONCLUSIONS: The novel profile identified in this study suggests the existence of more than two rod pathways. The distinctive ERG feature was not observed in patients with X-linked CSNB1 and additional affected individuals with unknown molecular defect. These observations will help to discriminate autosomal recessive from X-linked recessive cases by ERG and molecular genetic analysis.
PURPOSE:Congenital stationary night blindness (CSNB) is a group of nonprogressive retinal disorders characterized by impaired night vision that occurs in autosomal dominant, autosomal recessive, or X-linked forms. Autosomal recessive (ar)CSNB seems to be very rare. Mice lacking the metabotropic glutamate receptor 6 (Grm6) have a defect in signal transmission from the photoreceptors to ON-bipolar cells. In the current study, the human orthologue (GRM6) was screened as a likely candidate for arCSNB. METHODS:arCSNB individuals of five families were screened for mutations in GRM6. Subsequently, they were examined with standard and 15-Hz flicker electroretinography (ERG). These recordings were compared with those of patients with X-linked CSNB1. RESULTS: Affected individuals in three of five families carried either compound heterozygous or homozygous mutations in GRM6. Strikingly, all of them displayed a distinctive abnormality of the rod pathway signals on scotopic 15-Hz flicker ERG. CONCLUSIONS: The novel profile identified in this study suggests the existence of more than two rod pathways. The distinctive ERG feature was not observed in patients with X-linked CSNB1 and additional affected individuals with unknown molecular defect. These observations will help to discriminate autosomal recessive from X-linked recessive cases by ERG and molecular genetic analysis.
Authors: Mieke M C Bijveld; Frans C C Riemslag; Astrid M L Kappers; Frank P Hoeben; Maria M van Genderen Journal: Doc Ophthalmol Date: 2011-09-27 Impact factor: 2.379
Authors: Mieke M C Bijveld; Astrid M L Kappers; Frans C C Riemslag; Frank P Hoeben; Anne C L Vrijling; Maria M van Genderen Journal: Doc Ophthalmol Date: 2011-09-24 Impact factor: 2.379
Authors: Miranda L Scalabrino; Sanford L Boye; Kathryn M H Fransen; Jennifer M Noel; Frank M Dyka; Seok Hong Min; Qing Ruan; Charles N De Leeuw; Elizabeth M Simpson; Ronald G Gregg; Maureen A McCall; Neal S Peachey; Shannon E Boye Journal: Hum Mol Genet Date: 2015-08-26 Impact factor: 6.150