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We were interested to read the letter by Patel et al reporting the unusual and striking fundus appearance of retinal arteriolar calcification in association with chronic renal failure.1 However, we feel that two important conditions have been omitted from the comment, which merit further discussion.
Firstly, Monckeberg’s sclerosis, which in its classic form is characterised by “pipe stem” calcific deposition in the medial coat of muscular arteries in middle aged and elderly individuals,2 and is described with widespread systemic distribution.3,4 Interestingly though, a juvenile form is seen, particularly in association with chronic renal failure and diabetes.5 The pathological mechanism of Monckeberg’s sclerosis is uncertain, but is thought to encompass elements both of dystrophic and metastatic calcification.6 In the reported case, it would be of interest to know if there was any evidence of vascular calcification elsewhere in this individual, or whether it was localised to the retinal arterioles only.
Secondly, Senior-Loken syndrome (renal-retinal syndrome, nephronophthisis associated with retinitis pigmentosa, or retinal aplasia) is also germane to this discussion.7 Nephronophthisis is a major cause of progressive medullary cystic renal disease leading to chronic renal failure in adolescents.8 It is associated with a variable retinal phenotype, a reflection of both clinical and genetic heterogeneity. When associated with retinitis pigmentosa, there is an absence of the classic bone spicule pigmentation, but optic nerve head pallor and attenuation of the blood vessels is seen. Also, electroretinographic alterations have been reported in nephronophthisis despite normal a normal fundus examination.9 In view of the phenotypic overlap seen with the reported case, results of electroretinography would be pertinent to the discussion. We would also advocate a molecular genetic analysis at the known loci associated with Senior-Loken syndrome, which could potentially reveal an interesting new allelic variant.
Finally, while the fundus photograph elegantly demonstrates the stark changes seen in the retinal vasculature; this evidence could be further augmented by the addition of an ultrasound B-scan image demonstrating the pathognomonic echogenic features of intraocular calcification.