![]() ![]() 2021 compared induced pluripotent stem cells (iPSC)-derived RPEs from individuals with DHRD to their controls. Their research also showed that R345W knock in mice demonstrated evidence of alterations in RPE cell ultrastructure, and that basal deposits and alterations in RPE cell ultrastructure were associated with increased with increased levels of C3 compliment activation. They stated that the deposits may contain increased amounts of mutated EFEMP1 proteins as well as TIMP3 protein, and that this may lead to basal deposit formation. 2007 proved the EFEMP1 mutation to be pathological by showing EFEMP1 R345W knock in mice develop deposits between Bruch's membrane and retinal pigment epithelium (RPE). Normally, EFEMP1 is widely expressed in the extracellular matrix, however, its exact function is unknown.įu et al. Since Doyne Honeycomb Retinal Dystrophy results from an autosomal dominant mutation in the EFEMP1 gene, having an affected family member is the only identifiable risk factorĭoyne Honeycomb Retinal Dystrophy is characterized by an autosomal dominant mutation in the EFEMP1 gene, specifically a single missense Arg345Trp (R345W) mutation in exon 10.ĮFEMP1 stands for EGF-containing fibulin-like extracellular matrix protein 1, and the gene coding for it lies on chromosome 2p16. identified a single mutation in the EFEMP1 gene on chromosome 2 in both families with DHRD and MLVT, confirming that the two represented slight phenotypic variances of the same disease, and thus we now consider them to be the same clinical entity. Even in light of this discovery in 1996, it was still thought that the two diseases may represent separate entities. Ophthalmologists did suspect for a period of time that the two separately described entities likely referenced the same disease given their similarities, and in 1996 both DHRD and MLVT were mapped to abnormalities in chromosome 2, first by Heon in patients with MLVT, then by Gregory shortly after for patients with DHRD. Vogt in 1925 then described a similar phenotypic picture in a cluster of likely related individuals in the Leventine Valley of Switzerland, thus spawning the name Malattia Leventinese (MLVT). He found that each had an early onset retinal dystrophy with closely grouped white lesions in the macula and disc area which he termed "Honeycomb" pattern. H35.54 - Dystrophies primarily involving the retinal pigment epitheliumĭoyne Honeycomb Retinal Dystrophy (DHRD) was first described phenotypically by Doyne in 1899 in four sisters in England.H35.53 - Other dystrophies primarily involving the sensory retina.H35.50 - Unspecified hereditary retinal dystrophy.Doyne Honeycomb Retinal Dystrophy (DHRD) or Malattia Leventinese (MLVT) or Dominant Drusen can be coded under the header H35.5 for Hereditary Retinal Dystrophy. ![]()
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