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This abstract is assigned to session SBO-BOG Free papers: Genetica/Génétique

Title

A common NYX mutation in Flemish patients with X-linked CSNB

Purpose	The Schubert-Bornschein type of complete congenital stationary night blindness (CSNB) is a genetically heterogeneous retinal disorder. So far mutations in two genes, NYX and GRM6 have been associated with this type of CSNB. The purpose of this study was to identify the genetic defect in affected male patients from Flemish families with complete CSNB and X-linked inheritance.
Methods	Probands with CSNB from 3 large Flemish families underwent an extensive ophthalmologic examination. DNA was extracted from peripheral blood and the coding region of NYX along with parts of the 5`UTR and 3`UTR and intronic regions covering the splice sites were PCR amplified and sequenced.
Results	In affected individuals with the complete form of CSNB a novel NYX mutation, c.855delG was identified. This deletion is predicted to lead to a frameshift mutation, p.Asp286ThrfsX62, resulting in a premature stop codon.
Conclusion	The c.855delG deletion in NYX seems to be a common mutation associated with CSNB in the Flemish population from Belgium. Hence, we suggest performing diagnostic testing for CSNB in the Flemish population initially directed towards the identification of this mutation. Subsequent screening for other mutations in NYX or GRM6 can then be performed as a second step.

Author 1

Last name	LEROY
Initials	BP
Department	Dept of Ophthalmology & Ctr for Med Genetics, Ghent University Hospital
City	Ghent

Author 2

Last name	BUDDE
Initials	BS
Department	Cologne Ctr of Genomics & Inst for Genetics, University of Cologne
City	Köln

Author 3

Last name	WITTMER
Initials	M
Department	Div of Med Molec Genetics & Gene Diagnostics, Inst of Med Genetics, University of Zurich
City	Schwerzenbach

Author 4

Last name	DE BAERE
Initials	E
Department	Ctr for Med Genetics, Ghent University Hospital
City	Ghent

Author 5

Last name	BERGER
Initials	W
Department	Div of Med Molec Genetics & Gene Diagnostics, Inst of Med Genetics, University of Zurich
City	Schwerzenbach

Author 6

Last name	ZEITZ
Initials	C
Department	Dept of Genetics, Inst de la Vision, Université Pierre et Marie Curie Paris 6
City	Paris