Not at all sure that this abstract is of any actual use - at present. Fascinating though it is. The fact that it is independent of thyroid hormone levels is, I feel, important.
Is there any possibility of looking at this in reverse and using eye tests at least to help confirm resistance to thyroid hormone (reduced sensitivity to thyroid hormone)? Better check that it is common across everyone who suffers this before making any assumptions.
J Clin Endocrinol Metab. 2017 Mar 31. doi: 10.1210/jc.2016-3671. [Epub ahead of print]
Retinal photoreceptor functions are compromised in patients with resistance to thyroid hormone syndrome (RTHβ).
Campi I1,2, Cammarata G3, Bianchi Marzoli S3, Beck-Peccoz P4, Santarsiero D3, Dazzi D5, Bottari de Castello A6, Taroni EG6, Viola F4,6, Mian C7, Watuntantrige-Fernando S7, Pelusi C8, Muzza M9, Maffini MA9, Persani L1,4.
1 Division of Endocrine and Metabolic Diseases & Lab. of Endocrine and Metabolic Research, IRCCS Istituto Auxologico Italiano, Piazzale Brescia 20, 20149 Milano, Italy.
2 Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy.
3 Neuro-Ophthalmology Service and Electrophysiology Laboratory, Department of Ophthalmology, IRCCS Istituto Auxologico Italiano Milan, Italy.
4 Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza 35, 20122 Milano.
5 Division of Internal Medicine, Ospedale Vaio Via Don Enrico Tincati n. 5 43036 Fidenza (PR), Italy.
6 Ophtalmology Unit, Fondazione IRCCS Ca' Granda, Via Francesco Sforza 35, 20122 Milan, Italy.
7 Department of Medicine (DIMED), Endocrinology Unit- University of Padua, Via Ospedale Civile n. 105, 35128 Padova.
8 Division of Endocrinology, Department of Medical & Surgical Sciences (DIMEC), University of Bologna, S. Orsola-Malpighi Hospital, Bologna, Italy.
9 Endocrine Unit, Fondazione IRCCS Ca' Granda, Via Francesco Sforza 35, 20122 Milan, Italy.
In animal models, disruption of thyroid hormone receptor-beta (TRβ) reduces the medium-wavelength (L/M) and increases the short-wavelength (S)-cones. The retinal photoreceptors (RPs) functions are unknown in patients with resistance to thyroid hormone syndrome with dominant-negative TRβ mutations (RTHβ).
to investigate RPs function in RTHβ.
DESIGN, SETTING AND PARTICIPANTS:
case-control study involving 27 RTHβ patients and 31 age-gender-matched controls, conducted in two tertiary referral centers in Italy.
MAIN OUTCOME MEASURES:
colour vision sensitivity assessed by Farnsworth with calculation of Total Score Error (TES); central macular thickness (CMT) of the outer retinal layer measured by Spectral Domain-Optical Coherence Tomography (SD-OCT); retinal function tested by full-field electroretinogram (ERG) and S-cone ERG.
mean TES was worse in RTHβ than controls (p 0.002). CMT was overlapping between the study groups, but directly correlated with SHBG levels in RTHβ. We found a statistically significant reduction in amplitude of the cone (P=0.024) and also of the rod response (p=0.006) in the ERG of RTHβ compared to controls. The response of the L/M-cones measured by a specialized ERG test was lower in RTHβ than controls (P=0.027), while no differences were found in the S-cone response. No correlations were found between serum thyroid hormones (TH) levels, TES or electrophysiological results. Furthermore, no differences were found between patients with maternal or de-novo/paternal inheritance.
We report the first in vivo evidence of functional defects of RPs in RTHβ. These changes occur independently of endogenous TH levels or the prenatal exposure to high or normal maternal TH.