Purchase this article with an account.
Avery H. Weiss, John P. Kelly, Samir Deeb; Blue-cone Monochromacy In A Patient With Compound Heterozygosity For Mutations In Thyroid Hormone Receptor Beta 2 Gene. Invest. Ophthalmol. Vis. Sci. 2011;52(14):4894.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To describe the first case of blue-cone monochromatism (BCM) in an infant with severe thyroid hormone resistance due to mutations in the gene (THRβ2) encoding thyroid hormone receptor beta 2 (Trβ2).
We PCR-amplified and directly sequenced exons 8-10 of the THRβ2 gene in a child with blue cone monochromacy documented by electroretinogram (ERG) testing including spectral stimuli.
Molecular analysis revealed that the child is a compound heterozygote for p.R338W and p.R429W mutations in the THRβ2 gene. These two mutations lie within the ligand-binding domain but are known to selectively inhibit Trβ2 binding as homodimers to the thyroid hormone receptor response elements (TREs). ERG testing showed a reduced photopic response. Spectral testing on a white background showed a small amplitude b-wave (11 µV) to the red flash and a larger amplitude b-wave (31 µV) to the blue flash.
This report is the first to document BCM caused by deleterious mutations in the THRβ2 gene. Therefore, thyroid hormone, via TRβ2, is critical for middle-wave-sensitive (MWS) and long-wave-sensitive (LWS) cone development in the fovea and peripheral retina in humans.
This PDF is available to Subscribers Only