Recommended panel testing at Breda Genetics for this condition:
Summary
The term fleck retina is used to describe fundus conditions characterized by multiple yellowish-white lesions of various size and configuration, without vascular or optic nerve abnormalities. Originally this group consisted of the following disorders: fundus albipunctatus, fundus flavimaculatus, basal laminar drusen (also known as familial drusen), familial benign fleck retina and fleck retina of Kandori. However, also some primary hereditary ocular diseases may be included such as retinitis punctata albescens or Bietti crystalline dystrophy, Kjellin syndrome, secundary retinal flecks due to metabolic disorders such as Alport syndrome, cystinosis, oxalosis or membrano-proliferative glomerulonephritis. Drug-related causes may include Tamoxifen or Canthaxanthin.
The demonstration of a dot-and-fleck retinopathy in any individual with a family history of Alport syndrome or with end-stage renal disease is diagnostic of Alport syndrome. In such instances, the molecular analysis of the Alport syndrome panel genes is recommended.
Molecular genetics
Fundus flavimaculatus (Stargardt disease type 1) can be caused by mutations in the ABCA4 gene.
RDH5 and RLBP1 mutations cause fundus albipunctatus. RDH5 mutations can also cause familial benign fleck retina with night blindness.
Drusen are extracellular deposits that accumulate below the retinal pigment epithelium on Bruch membrane. ‘Basal laminar drusen’ refers to an early adult-onset drusen phenotype that shows a pattern of uniform small, slightly raised yellow subretinal nodules randomly scattered in the macula. Of note, CFH mutations can cause membranoproliferative glomerulonephritis type II (MPGN II).
PLA2G5 mutations have been found to cause familial benign fleck retina.
Retinitis punctata albescens can be caused by mutation in PRPH2, RHO or RLBP1.
Bietti crystalline dystrophy is caused by homozygous or compound heterozygous mutation in the CYP4V2 gene. Bietti crystalline dystrophy is a form of corneoretinal dystrophy characterized by numerous tiny glistening yellow-white crystals at the posterior pole of the retina, associated with atrophy of the retinal pigment epithelium (RPE), pigment clumps, and choroidal sclerosis.
Kjellin syndrome, today better known as spastic paraplegia 15 (SPG15) is a neurodegenerative disorder characterized by progressive spasticity primarily affecting the lower limbs. It is a complex form of spastic paraplegia, associated with other neurologic dysfunction, including variable mental retardation, hearing and visual defects, and thin corpus callosum. It is caused by mutations in the ZFYVE26 gene and is transmitted in an autosomal recessive fashion.
Pigmentary changes with retinal pigment epithelial mottling may be seen in children with cystinosis, which is caused by mutations in the CTNS gene.
A crystalline retinopathy which may lead to slowly progressive visual loss can be seen in primary hyperoxaluria type 1 (AGXT gene mutations).
Fleck retina of Kandori is a very rare cases of congenital non-progressive night blindness characterized by irregular flecks, variable in size, distributed in the equatorial region or between the equatorial and macular regions with a tendency to confluence. No gene has been so far identified.
Recommended testing workflow
Recommended panel testing at Breda Genetics for this condition:
References:
Alport syndrome. A review of the ocular manifestations. Colville DJ, Savige J. Ophthalmic Genet. 1997 Dec;18(4):161-73. PMID: 9457747
Flecked retina disorders. De Laey JJ. Bull Soc Belge Ophtalmol. 1993;249:11-22. PMID: 7952338
Biallelic mutations in PLA2G5, encoding group V phospholipase A2, cause benign fleck retina. Sergouniotis PI, Davidson AE, Mackay DS, Lenassi E, Li Z, Robson AG, Yang X, Kam JH, Isaacs TW, Holder GE, Jeffery G, Beck JA, Moore AT, Plagnol V, Webster AR. Am J Hum Genet. 2011 Dec 9;89(6):782-91. PMID: 22137173
Compound heterozygous RDH5 mutations in familial fleck retina with night blindness. Hayashi T, Goto-Omoto S, Takeuchi T, Gekka T, Ueoka Y, Kitahara K. Acta Ophthalmol Scand. 2006 Apr;84(2):254-8. PMID: 16637847
