Mapping X-linked ophthalmic diseases. III. Provisional assignment of the locus for blue cone monochromacy to Xq28
R. A. Lewis, J. D. Holcomb, W. C. Bromley, M. C. Wilson, T. H. Roderick and J. F. Hejtmancik
Blue cone monochromacy (BCM) is an infrequent X-linked retinal disorder
typified by poor central visual acuity and color discrimination, early
onset of nystagmus, variable degrees of myopia and astigmatism, and a
nearly normal retinal appearance. The physiologic functions of rods and
blue cones are preserved. The regional location of the genetic mutation
causing BCM has been unknown. We have applied the modern molecular
techniques of analysis of restriction fragment length polymorphisms to
three multigenerational kindreds in which BCM is segregating. Significant
linkage is established to two DNA markers, DXS15 and DXS52, each of which
maps to the vicinity of Xq28. Regional localization of the locus for BCM
has the potential to improve carrier detection and to provide antenatal
diagnosis in families at risk for the disease.
