OCULAR MANIFESTATIONS OF ASP38ALA AND THR59LYS FAMILIAL TRANSTHYRETIN AMYLOIDOSIS.

PURPOSE: To describe the ophthalmic manifestations of familial transthyretin amyloidosis (FTA) mutations, including Asp38Ala and Thr59Lys, which have not been previously reported to have ocular involvement. METHODS: This is an observational case series of prospectively collected data of 16 patients with FTA who were taking tafamidis for mild peripheral neuropathy and underwent a comprehensive ophthalmic examination at a single tertiary center, between January 2013 and March 2020. The ocular involvement of each FTA mutation type and the specific manifestations were the main outcome measures. RESULTS: Six of 16 patients with FTA manifested ocular involvement. Ocular involvement was noted in two of three patients with Glu89Lys mutations having retinal deposits, retinal hemorrhages, and corneal opacity. Three of nine patients with Asp38Ala mutations and one of two patients with Thr59Lys mutations showed ocular involvement that had not been previously described. The ophthalmic findings included glaucoma, anterior lens capsule opacity, vitreous opacity, and retinal deposits. The decrease in vascular flow due to perivascular cuffing of the amyloid deposits was detected by optical coherence tomography angiography. CONCLUSION: The current study newly described that two transthyretin mutation types of FTA, Asp38Ala and Thr59Lys, may manifest with ocular findings such as anterior lens capsule opacity and retinal deposits.

Alport syndrome with bilateral simultaneous anterior and posterior lenticonus with severe temporal macular thinning.

Alport syndrome (AS) is a hereditary disease with various modes of inheritance, X-linked being the the most common. Anterior lenticonus is the characteristic abnormality along with perimacular and peripheral fleck retinopathy. Our two cases of AS had simultaneous anterior and posterior lenticonus with severe temporal macular thinning on optical coherence tomography with no specific renal symptomatology and were diagnosed as AS without any invasive renal biopsy. First patient was a 19-year-old man who presented with compound myopia due to bilateral anterior and posterior lenticonus with perimacular fleck retinopathy and lozenge sign and bilateral moderate sensorineural hearing loss (SNHL). Second patient was a 24-year-old man who presented with difficulty in vision due to bilateral anterior and posterior lenticonus with bilateral severe SNHL. Our cases emphasise the crucial role of an ophthalmologist in diagnosing AS before the onset of renal symptoms and prompting further nephrological work-up in the patient or the carrier.

Mutation in the mouse histone gene Hist2h3c1 leads to degeneration of the lens vesicle and severe microphthalmia.

During an ENU (N-ethyl-N-nitrosourea) mutagenesis screen, we observed a dominant small-eye mutant mouse with viable homozygotes. A corresponding mutant line was established and referred to as Aey69 (abnormality of the eye #69). Comprehensive phenotyping of the homozygous Aey69 mutants in the German Mouse Clinic revealed only a subset of statistically significant alterations between wild types and homozygous mutants. The mutation causes microphthalmia without a lens but with retinal hyperproliferation. Linkage was demonstrated to mouse chromosome 3 between the markers D3Mit188 and D3Mit11. Sequencing revealed a 358 A-> C mutation (Ile120Leu) in the Hist2h3c1 gene and a 71 T-> C (Val24Ala) mutation in the Gja8 gene. Detailed analysis of eye development in the homozygous mutant mice documented a perturbed lens development starting from the lens vesicle stage including decreasing expression of crystallins as well as of lens-specific transcription factors like PITX3 and FOXE3. In contrast, we observed an early expression of retinal progenitor cells characterized by several markers including BRN3 (retinal ganglion cells) and OTX2 (cone photoreceptors). The changes in the retina at the early embryonic stages of E11.5-E15.5 happen in parallel with apoptotic processes in the lens at the respective stages. The excessive retinal hyperproliferation is characterized by an increased level of Ki67. The hyperproliferation, however, does not disrupt the differentiation and appearance of the principal retinal cell types at postnatal stages, even if the overgrowing retina covers finally the entire bulbus of the eye. Morpholino-mediated knock-down of the hist2h3ca1 gene in zebrafish leads to a specific perturbation of lens development. When injected into zebrafish zygotes, only the mutant mouse mRNA leads to severe malformations, ranging from cyclopia to severe microphthalmia. The wild-type Hist2h3c1 mRNA can rescue the morpholino-induced defects corroborating its specific function in lens development. Based upon these data, it is concluded that the ocular function of the Hist2h3c1 gene (encoding a canonical H3.2 variant) is conserved throughout evolution. Moreover, the data highlight also the importance of Hist2h3c1 in the coordinated formation of lens and retina during eye development.

The Function of Thioredoxin-Binding Protein-2 (TBP-2) in Different Diseases.

Thioredoxin-binding protein-2 (TBP-2) has an important role in the redox system, but it plays a different role in many different diseases (e.g., various cancers, diabetes mellitus (DM), cardiovascular disease, and cataracts) by influencing cell proliferation, differentiation, apoptosis, autophagy, and metabolism. Distinct transcription factors (TFs) stimulated by different factors combine with binding sites or proteins to upregulate or downregulate TBP-2 expression, in order to respond to the change in the internal environment. Most research disclosed that the main function of TBP-2 is associating with thioredoxin (Trx) to inhibit the antioxidant capacity of Trx. Furthermore, the TBP-2 located in tissues, whether normal or abnormal, has the ability to cause the dysfunctioning of cells and even death through different pathways, such as shortening the cell cycle and inducing apoptosis or autophagy. Through these studies, we found that TBP-2 promoted the development of diseases which are involved in inflammatory and oxidative damage. To a certain extent, we believe that there is some hidden connection between the biological functions which TBP-2 participates in and some distinct diseases. This review presents only a summary of the roles that TBP-2 plays in cancer, DM, cataracts, and so on, as well as its universal mechanisms. Further investigations are needed for the cell signaling pathways of the effects caused by TBP-2. A greater understanding of the mechanisms of TBP-2 could produce potential new targets for the treatment of diseases, including cancer and diabetes, cardiovascular disease, and cataracts.

Identification and Functional Characterization of a GSH Conjugate Efflux Pathway in the Rat Lens.

PURPOSE: To identify and functionally characterize transporters involved in the release of glutathione (GSH) conjugates from the rat lens. METHODS: Polymerase chain reaction and Western blotting were used to screen for the presence of multidrug resistance-associated protein (Mrp) and organic anion transporting polypeptide (Oatp) isoforms, and immunohistochemistry used to localize Mrp isoforms. To test for Mrp function, lenses were loaded with 5-chloromethylfluorescein diacetate and monochlorobimane to form the fluorescent GSH conjugates glutathione methylfluorescein (GS-MF) and glutathione bimane (GS-B), respectively, and cultured in artificial aqueous humour (AAH) in the presence or absence of MK571, an Mrp-specific inhibitor, or benzbromarone, a nonspecific organic anion transporter inhibitor. Glutathione-MF and GS-B fluorescence were measured in the AAH media and lenses. RESULTS: Multidrug resistance-associated proteins 1, 4, 5, and Oatp1a4 were present at the transcript level, but only Mrp1, 4, and 5 were detected at the protein level. Multidrug resistance-associated proteins 1 and 5 localized to the epithelium and peripheral fiber cells, whereas Mrp4 strongly labeled the nuclei. Glutathione-MF and GS-B efflux was significantly decreased and accumulation in the lens significantly increased in the presence of MK571, indicating that the Mrps are the predominant transporters involved in GSH conjugate release from the lens. Glutathione-B conjugate efflux was further inhibited in the presence of benzbromarone, suggesting that alternative organic anion pathways were involved in mediating GS-B efflux. CONCLUSIONS: Multidrug resistance-associated proteins are present in the lens and may be used to remove endogenous and exogenous compounds from the lens via GSH conjugation. This may represent an important pathway of detoxification required to minimize oxidative stress and maintain lens homeostasis.

FE65 and FE65L1 amyloid precursor protein-binding protein compound null mice display adult-onset cataract and muscle weakness.

FE65 and FE65L1 are cytoplasmic adaptor proteins that bind a variety of proteins, including the amyloid precursor protein, and that mediate the assembly of multimolecular complexes. We previously reported that FE65/FE65L1 double knockout (DKO) mice display disorganized laminin in meningeal fibroblasts and a cobblestone lissencephaly-like phenotype in the developing cortex. Here, we examined whether loss of FE65 and FE65L1 causes ocular and muscular deficits, 2 phenotypes that frequently accompany cobblestone lissencephaly. Eyes of FE65/FE65L1 DKO mice develop normally, but lens degeneration becomes apparent in young adult mice. Abnormal lens epithelial cell migration, widespread small vacuole formation, and increased laminin expression underneath lens capsules suggest impaired interaction between epithelial cells and capsular extracellular matrix in DKO lenses. Cortical cataracts develop in FE65L1 knockout (KO) mice aged 16 months or more but are absent in wild-type or FE65 KO mice. FE65 family KO mice show attenuated grip strength, and the nuclei of DKO muscle cells frequently locate in the middle of muscle fibers. These findings reveal that FE65 and FE65L1 are essential for the maintenance of lens transparency, and their loss produce phenotypes in brain, eye, and muscle that are comparable to the clinical features of congenital muscular dystrophies in humans.

Anterior lentiplane associated with posterior lenticonus and microcornea.

We report a 12-year-old boy with a rare condition consisting of familial bilateral anterior lentiplane (a flat anterior lens capsule) posterior lenticonus, and microcornea.

MAPK1 is required for establishing the pattern of cell proliferation and for cell survival during lens development.

The mitogen-activated protein kinases (MAPKs; also known as ERKs) are key intracellular signaling molecules that are ubiquitously expressed in tissues and were assumed to be functionally equivalent. Here, we use the mouse lens as a model system to investigate whether MAPK1 plays a specific role during development. MAPK3 is known to be dispensable for lens development. We demonstrate that, although MAPK1 is uniformly expressed in the lens epithelium, its deletion significantly reduces cell proliferation in the peripheral region, an area referred to as the lens germinative zone in which most active cell division occurs during normal lens development. By contrast, cell proliferation in the central region is minimally affected by MAPK1 deletion. Cell cycle regulators, including cyclin D1 and survivin, are downregulated in the germinative zone of the MAPK1-deficient lens. Interestingly, loss of MAPK1 subsequently induces upregulation of phosphorylated MAPK3 (pMAPK3) levels in the lens epithelium; however, this increase in pMAPK3 is not sufficient to restore cell proliferation in the germinative zone. Additionally, MAPK1 plays an essential role in epithelial cell survival but is dispensable for fiber cell differentiation during lens development. Our data indicate that MAPK1/3 control cell proliferation in the lens epithelium in a spatially defined manner; MAPK1 plays a unique role in establishing the highly mitotic zone in the peripheral region, whereas the two MAPKs share a redundant role in controlling cell proliferation in the central region of the lens epithelium.

Retinal ganglion cell survival and axon regeneration in WldS transgenic rats after optic nerve crush and lens injury.

BACKGROUND: We have previously shown that the slow Wallerian degeneration mutation, whilst delaying axonal degeneration after optic nerve crush, does not protect retinal ganglion cell (RGC) bodies in adult rats. To test the effects of a combination approach protecting both axons and cell bodies we performed combined optic nerve crush and lens injury, which results in both enhanced RGC survival as well as axon regeneration past the lesion site in wildtype animals. RESULTS: As previously reported we found that the Wld(S) mutation does not protect RGC bodies after optic nerve crush alone. Surprisingly, we found that Wld(S) transgenic rats did not exhibit the enhanced RGC survival response after combined optic nerve crush and lens injury that was observed in wildtype rats. RGC axon regeneration past the optic nerve lesion site was, however, similar in Wld(S) and wildtypes. Furthermore, activation of retinal glia, previously shown to be associated with enhanced RGC survival and axon regeneration after optic nerve crush and lens injury, was unaffected in Wld(S) transgenic rats. CONCLUSIONS: RGC axon regeneration is similar between Wld(S) transgenic and wildtype rats, but Wld(S) transgenic rats do not exhibit enhanced RGC survival after combined optic nerve crush and lens injury suggesting that the neuroprotective effects of lens injury on RGC survival may be limited by the Wld(S) protein.

Crystal deposits on the lens capsules in Bietti crystalline corneoretinal dystrophy associated with a mutation in the CYP4V2 gene.

PURPOSE: We report a patient (Case 1) with Bietti crystalline corneoretinal dystrophy (BCD) associated with previously unknown findings of crystal-like deposits on the anterior and posterior lens capsules. This patient is one of four (Cases 1-4) in whom we have found BCD associated with the same mutation in the CYP4V2 gene. METHODS: We present a case report with molecular diagnosis. A 45-year-old man (Case 1) was referred to our clinic with complaints of gradual progression of visual disturbances and night blindness. His visual acuity was limited to hand movement bilaterally. Slit-lamp biomicroscopy disclosed glistening, crystal-like deposits on the anterior and posterior lens capsules, as well as on the corneal stroma near the corneoscleral limbus. No such deposit was found in the lens stroma. Fundus examination disclosed profound chorioretinal atrophy with scarce crystal deposits. Full-field electroretinography showed extinguished responses of isolated rods, isolated cones, and mixed rods and cones. RESULTS: Molecular genetic analysis revealed that the subject had a homozygous mutation in the CYP4V2 gene (IVS6-8delTCATACAGGTCATCGCG/insGC), which is most commonly found in Japanese patients with BCD. Three other cases (Cases 2-4) of BCD associated with the same mutation did not show such crystal-like deposits on the lens surface. CONCLUSIONS: Although their exact origin remains unknown, crystal-like deposits may appear on the lens capsule of patients with BCD associated with a mutation in the CYP4V2 gene.

[Ocular findings in Alport syndrome: 32 case studies]. / Atteinte oculaire au cours du syndrome d'Alport. A propos de 32 cas.

BACKGROUND: Alport syndrome is an inherited disease resulting in kidney failure, hearing loss, and ocular abnormalities. The purpose of this study was to describe the incidence and type of ocular abnormalities and to determine inheritance of this syndrome in our population. PATIENTS AND METHODS: A total of 32 patients, from ten different families in South Tunisia, underwent a complete ocular examination. Inheritance was determined using pedigrees and genotyping. RESULTS: The best corrected visual acuity was 7.6/10. Biomicroscopy showed polymorphous dystrophy in 3%, anterior lenticonus in 28%, lens opacities in 3%, cataract in 19%, and retinal flecks in 37%. The genetic survey found five families with X-linked Alport syndrome, four families with recessive autosomal disease, and one family with dominant autosomal disease. DISCUSSION: Ocular abnormalities have been reported in 9%-82% of Alport syndrome patients. They are rare in childhood and increase in frequency and severity with age. The types of ocular defects described mostly involve the lens, the retina and more rarely the cornea. The most common changes are anterior lenticonus and perimacular retinal flecks. In approximately 85%, Alport syndrome is X-linked. In the remaining 15%, the transmission is autosomal recessive and exceptionally autosomal dominant. CONCLUSION: Ocular examination is a precious help for Alport syndrome diagnosis. It can also determine the prognosis of nephropathy.

The use of ocular abnormalities to diagnose X-linked Alport syndrome in children.

The diagnosis of X-linked Alport syndrome is often difficult, but the demonstration of lenticonus and retinopathy may facilitate the diagnosis in adult patients. The aim of this study was to determine the diagnostic usefulness of ocular examination in children. Fourteen families with at least one affected child were studied clinically, and COL4A5 mutations were determined. The families included 15 affected boys (median age 11 years, range 4-19 years). Two boys (13%) had renal failure, nine (60%) had a known hearing loss, one (7%) had lenticonus and five (33%) had a central (4/15, 27%) or peripheral (4/14, 29%) retinopathy. Lenticonus and retinopathy were first noted in 14 and 11 year olds, respectively. All boys with retinopathy had a hearing loss. The early onset retinopathy was associated with a severe mutation (Q1383X). Eight families (8/14, 57%) comprised only sons and mothers, and two mothers (2/12, 17%) had the retinopathy. Six boys (40%) would have been diagnosed with Alport syndrome on the basis of their own or their mother's ocular examinations. None of the six girls (median age 8 years, range 7-14 years) had ocular abnormalities. Hearing loss is usually highly sensitive for the diagnosis of Alport syndrome, but ocular examination of boys and their mothers at the initial consultation is a non-invasive test that is helpful in up to 40% cases.

CTRP5 is a membrane-associated and secretory protein in the RPE and ciliary body and the S163R mutation of CTRP5 impairs its secretion.

PURPOSE: In a prior study, a S163R mutation in the complement-1q tumor necrosis factor-related protein 5 (CTRP5/ C1QTNF5) was reported to be associated with early-onset long anterior zonules (LAZ) and late-onset retinal degeneration (L-ORD). The ocular tissues involved in the phenotype are the retinal pigment epithelium (RPE) in the posterior segment and ciliary epithelium (CE) and lens in the anterior segment. The purpose of this study was to characterize the spatial and temporal expression of the mouse Ctrp5 gene, determine tissue and subcellular localization, and study the effect of the S163R mutation. METHODS: The expression of the Ctrp5 gene in the mouse was studied by quantitative (q)RT-PCR and in situ hybridization. CTRP5 protein expression and distribution were studied by Western blot analysis, immunohistochemistry, and immunoelectron microscopy. Cellular location of wild-type and mutant CTRP5 in MDCK and COS-7 cells was determined by immunofluorescence and immunoblot analysis. RESULTS: A significant level of Ctrp5 expression was detected in the adult mouse in the ciliary body (CB) and RPE, and expression started at a very early stage of embryogenesis. Immunohistochemical analysis showed CTRP5 protein in the apical processes of the RPE and forming a hexagonal lattice associated with the RPE lateral membranes. In the ciliary body, CTRP5 was localized to the apical aspects of the CE, the region between the bilayered ciliary epithelial cells. The membrane association of CTRP5 in the RPE and CE was further confirmed by immunoelectron microscopy. Furthermore, cultured cells were used to show that the CTRP5 is a secretory protein and that its secretion is impaired by the S163R mutation. CONCLUSIONS: CTRP5, a secretory and membrane-associated protein, is localized to the lateral and apical membranes of the RPE and CB. Impaired secretion of the mutant protein may underlie the pathophysiology of L-ORD and LAZ.

Diagnosis and management of bilateral posterior lenticonus in 7 members of the same family.

PURPOSE: To report on the occurrence of monosymptomatic bilateral posterior lenticonus in 7 members of the same family and discuss the diagnoses and methods of management. SETTING: Eye Clinic, Cantonal Hospital, Lucerne, Switzerland. METHODS: Two sisters were found to suffer from bilateral posterior lenticonus. The 3 sons of the elder sister and the 2 daughters of the younger sister all presented with bilateral posterior lenticonus. A cataract operation or a clear lens extraction with intraocular lens implantation was performed in 4 of the 7 patients. RESULTS: The disorder was found to be inherited and to follow a pattern of autosomal dominance. Visual acuity improved to 20/20 in all operated eyes. CONCLUSION: This may be the largest group in 1 family presenting with bilateral posterior lenticonus described to date. Treatment of posterior lenticonus, if necessary, can be successfully managed as an ordinary cataract.

Long anterior lens zonules in late-onset retinal degeneration (L-ORD).

PURPOSE: We report new findings of peripupillary iris atrophy and long anteriorly-inserted zonules in a family with late-onset retinal degeneration (L-ORD). DESIGN: The proband was noted to have anterior segment findings not previously described in L-ORD, an autosomal dominant condition resulting in severe visual impairment. A mutation in the C1QTNF5 (CTRP5) gene is causal. We identified family members with anterior segment findings. METHODS: Family members were examined with slit-lamp biomicroscopy and psychophysical tests including dark adaptation and visual fields. Genetic testing for the C1QTNF5 mutation was carried out. RESULTS: In this family with a proven mutation in this gene, peripupillary iris atrophy and abnormally long anterior zonular insertions were present before retinal changes and visual loss. CONCLUSIONS: Anterior segment findings have not previously been reported and along with impaired dark adaptation may serve as an early marker for this condition thus facilitating counseling and possible therapeutic intervention.

Late-onset macular degeneration and long anterior lens zonules result from a CTRP5 gene mutation.

PURPOSE: To identify the gene responsible for a complex ocular phenotype of late-onset macular degeneration, long anterior zonules (LAZ), and elevated intraocular pressure (IOP) and to study its expression. METHODS: Ocular examination, visual field, fluorescein angiography, and electrophysiology testing were performed. One affected individual was treated with vitamin A. DNA from 55 family members (UM:H389) was used for linkage, mapping, and mutation analysis. Linkage analysis of macular degeneration and LAZ phenotypes was performed independently. Mutations in candidate genes were screened by sequencing. mRNA expression of CTRP5 and MFRP, which are bicistronic genes, was studied by semiquantitative RT-PCR (qRT-PCR) in various human tissues. CTRP5 expression was also evaluated by in situ hybridization. RESULTS: Affected members had LAZ detectable by the third decade and/or macular degeneration by the fourth to fifth decade. A six-month treatment with vitamin A shortened dark adaptation considerably in one affected member. Both conditions mapped independently with zero recombination to 11q23, with maximum lod scores of 3.31 for macular degeneration and 5.41 for LAZ. The same CTRP5 missense mutation was identified in all affected individuals. Retinal pigment epithelium (RPE) and ciliary epithelium (CE) showed highest CTRP5 transcript expression, which was also true for MFRP. CTRP5 tissue expression was confirmed by in situ hybridization. CONCLUSIONS: A single locus at 11q23 is implicated in a complex ocular phenotype involving RPE and CE, tissues of neuroectodermal origin. All individuals with either LAZ and/or macular degeneration carry the same CTRP5 S163R mutation, which is transmitted in autosomal dominant manner.

Anterior lens capsule abnormalities in Alport syndrome.

Alport syndrome is a hereditary, progressive disease characterized by progressive nephritis, sensorineural deafness, and ocular abnormalities, including anterior lenticonus. The ultrastructure of the lens capsule abnormalities in Alport syndrome is reported. Four anterior lens capsules from 31-year-old patient and 26-year-old patient with lenticonus who were affected by the Alport syndrome were obtained at capsulectomy. And all four anterior lens capsules were examined by transmission electron microscopy. The histopathologic findings showed that the thickness of the anterior lens capsules was decreased (4-13 microm) and that there were many vascular dehiscences localized at the inner part of the lens capsule. There were large numbers of capsular dehiscences containing fibrillar materials and vacuoles. The anterior capsules were clearly fragile in this disease, forming the basis for the progressive lenticonus and anterior polar cataract.