Optic Disc Hypoplasia Assessment in PAX6 -Related Aniridia.

BACKGROUND: This study aims to characterize optic disc hypoplasia in congenital aniridia using ultra-wide-field imaging (UWFI) and nonmydriatic retinal photography (NMRP). We also investigated the relation between optic disc hypoplasia and foveal hypoplasia. METHODS: This is a retrospective case series of patients diagnosed with PAX6 -related aniridia in a National Referral Center, who underwent UWFI, NMRP, and spectral-domain optical coherence tomography (SD-OCT) . The disc diameter (DD) and the disc-to-fovea distance (DF) were measured. The DD:DF ratio was used to assess the relative size of the optic disc. The analyses were carried with respect to paired age- and sex-matched healthy controls. SD-OCT was used for foveal hypoplasia grading (from 1 to 4) and retinal nerve fiber layer (RNFL) analysis. RESULTS: Mean manual DD:DF ratio was 0.33 (95% CI: 0.31-0.35) in aniridia patients versus 0.37 (95% CI: 0.36-0.39) in control patients (n = 20, P = 0.005) measured on NMRP and 0.32 (95% CI: 0.30-0.35) in aniridia patients versus 0.37 (95% CI: 0.37-0.39) in control patients (n = 26, P < 0.0001) when assessed on UWFI. Mean semiautomated DD:DF ratio measured on UWFI in aniridia patients was 0.31 (95% CI: 0.29-0.33) versus 0.37 (95% CI: 0.36-0.38) in control patients ( P < 0.0001). Also, a negative correlation was found significant between the grade of foveal hypoplasia and the mean semiautomated DD:DF ratio (r = -0.52, 95% CI: -0.76 to -0.15, P = 0.0067). Finally, a significant negative correlation was found between the peripapillary temporal RNFL thickness and the grade of foveal hypoplasia ( P = 0.0034). CONCLUSIONS: The DD:DF ratio is significantly reduced in PAX6 -related aniridia patients and correlates with the severity of foveal hypoplasia. This ratio is a valuable tool for optic disc hypoplasia assessment in congenital aniridia, especially when provided semiautomatically by UWFI.

Reduction of lens size in PAX6-related aniridia.

Heterozygous mutation of PAX6 in humans leads to congenital aniridia (OMIM 106210) which is typified by congenital iris and foveal defects, and later onset glaucoma, aniridic keratopathy, and cataract. Mice heterozygous for Pax6 mutations phenocopy many aspects of aniridia including the iris defects, keratopathy and cataract, although Pax6 mutant mice have small lenses, a phenotype which is not typically reported in human aniridia, perhaps due to difficulties in measuring lens diameter during typical ophthalmic examinations as the lens periphery is shielded by the iris. In order to overcome this, records of patients diagnosed with congenital aniridia between April 2015 and May 2021 at the Necker-Enfants Malades Hospital, and genetically confirmed with a disease-causing PAX6 variant, were retrospectively reviewed for those with normal axial length whose iris defects allowed visualization of the lens margins and corneal diameter to allow calculation of a lens/corneal diameter ratio. This value was compared with values obtained from a cohort of patients with Sjödell grade IV oculocutaneous albinism type 1 (OCA1; OMIM 203100) which allowed visualization of the lens periphery via iris transillumination. This analysis revealed that patients with congenital aniridia had a significantly lower lens/corneal ratio when compared to those with albinism, suggesting that humans haploinsufficient for PAX6, like mice, rats, frogs, and zebrafish, exhibit reductions in lens size.

Optical Coherence Tomography Angiography Assessment in Congenital Aniridia.

PURPOSE: This study aims to characterize foveal vasculature assessed by optical coherence tomography angiography (OCT-A) in congenital aniridia which is hallmarked by foveal hypoplasia (FH). DESIGN: Cross-sectional case-control analysis. METHODS: At the National Referral Center for congenital aniridia, patients with confirmed PAX6-related aniridia and FH diagnosed on spectral-domain OCT (SD-OCT) with available OCT-A and matched control subjects were included. OCT-A was performed in patients with aniridia and control subjects. Foveal avascular zone (FAZ) and vessel density (VD) were collected. VD in the foveal and parafoveal areas at the level of the superficial and deep capillary plexi (SCP and DCP, respectively) were compared between the 2 groups. In patients with congenital aniridia, correlation between VD and the grading of FH was assessed. RESULTS: Among 230 patients with confirmed PAX6-related aniridia, high-quality macular B-scans and OCT-A were available in 10 patients. On the foveal area, mean VD was higher in aniridia patients (41.10%, n = 10) than in control subjects (22.65%, n = 10) at the level of the SCP and the DCP (P = .0020 and P = .0273, respectively). On the parafoveal area, mean VD was lower in patients with aniridia (42.34%, n = 10) than in healthy subjects (49.24%, n = 10) at the level of both plexi (P = .0098 and P = .0371, respectively). In patients with congenital aniridia, a positive correlation was found between the grading of FH and the foveal VD at the SCP (r = 0.77, P = .0106). CONCLUSIONS: Vasculature is altered in PAX6-related congenital aniridia, higher in foveal and lower in parafoveal areas, especially when FH is severe, which is consistent with the concept that the absence of retinal blood vessels is essential for foveal pit development.

Congenital aniridia beyond black eyes: From phenotype and novel genetic mechanisms to innovative therapeutic approaches.

Congenital PAX6-aniridia, initially characterized by the absence of the iris, has progressively been shown to be associated with other developmental ocular abnormalities and systemic features making congenital aniridia a complex syndromic disorder rather than a simple isolated disease of the iris. Moreover, foveal hypoplasia is now recognized as a more frequent feature than complete iris hypoplasia and a major visual prognosis determinant, reversing the classical clinical picture of this disease. Conversely, iris malformation is also a feature of various anterior segment dysgenesis disorders caused by PAX6-related developmental genes, adding a level of genetic complexity for accurate molecular diagnosis of aniridia. Therefore, the clinical recognition and differential genetic diagnosis of PAX6-related aniridia has been revealed to be much more challenging than initially thought, and still remains under-investigated. Here, we update specific clinical features of aniridia, with emphasis on their genotype correlations, as well as provide new knowledge regarding the PAX6 gene and its mutational spectrum, and highlight the beneficial utility of clinically implementing targeted Next-Generation Sequencing combined with Whole-Genome Sequencing to increase the genetic diagnostic yield of aniridia. We also present new molecular mechanisms underlying aniridia and aniridia-like phenotypes. Finally, we discuss the appropriate medical and surgical management of aniridic eyes, as well as innovative therapeutic options. Altogether, these combined clinical-genetic approaches will help to accelerate time to diagnosis, provide better determination of the disease prognosis and management, and confirm eligibility for future clinical trials or genetic-specific therapies.

Foveal Hypoplasia Grading in 95 Cases of Congenital Aniridia: Correlation to Phenotype and PAX6 Genotype.

PURPOSE: To correlate the degree of foveal hypoplasia in congenital aniridia with visual acuity, iris phenotype, and PAX6 mutations. DESIGN: Retrospective case series. METHODS: Ninety-five consecutive patients with high-quality spectral-domain optical coherence tomography records and available genotype were included in a single referral center. Iris hypoplasia was classified as complete, presence of iris root or remnants, and mild atypical aniridia. Spectral-domain optical coherence tomography images were assessed to classify foveal hypoplasia as grade 1 to 4 and to determine mean thicknesses for retinal layers. For statistical analysis 1 eye for each patient was used and 1 member of the same family has been included (n = 76 eyes). RESULTS: Most eyes (n= 158/169, 93.5%) showed variable degree of foveal hypoplasia. PAX6-positive patients presented higher degree of foveal hypoplasia than patients negative for PAX6 (P < .0001). PAX6 deletions, PAX6 variants subjected to nonsense-mediated decay and C-terminal extension variants were mostly associated with grade 3 or 4 foveal hypoplasia. Deletions restricted to the 3' flanking regulatory regions of PAX6 were associated with grade 1 or 2 foveal hypoplasia (P < .0001). Best-corrected visual acuity was higher and foveal outer retinal layers were thicker in patients with deletions in the 3' regulatory region of PAX6 (P = .001 and P < .0001). Patients with missense mutations presented with variable degree of foveal hypoplasia. The degree of foveal hypoplasia was most frequently correlated with the severity of iris defects, with 95% of eyes with complete aniridia presenting grade 3 or 4 foveal hypoplasia (P = .005). However, among eyes with mild iris phenotype, 70% (n=9/13) showed severe foveal hypoplasia. CONCLUSIONS: All types of PAX6 variants, even those associated with mild iris defects, may be at risk for severe foveal hypoplasia with poor visual prognosis, except for deletions restricted to the 3' regulatory PAX6 regions.

A new mouse mutant with cleavage-resistant versican and isoform-specific versican mutants demonstrate that proteolysis at the Glu441-Ala442 peptide bond in the V1 isoform is essential for interdigital web regression.

Two inherent challenges in the mechanistic interpretation of protease-deficient phenotypes are defining the specific substrate cleavages whose reduction generates the phenotypes and determining whether the phenotypes result from loss of substrate function, substrate accumulation, or loss of a function(s) embodied in the substrate fragments. Hence, recapitulation of a protease-deficient phenotype by a cleavage-resistant substrate would stringently validate the importance of a proteolytic event and clarify the underlying mechanisms. Versican is a large proteoglycan required for development of the circulatory system and proper limb development, and is cleaved by ADAMTS proteases at the Glu441-Ala442 peptide bond located in its alternatively spliced GAGß domain. Specific ADAMTS protease mutants have impaired interdigit web regression leading to soft tissue syndactyly that is associated with reduced versican proteolysis. Versikine, the N-terminal proteolytic fragment generated by this cleavage, restores interdigit apoptosis in ADAMTS mutant webs. Here, we report a new mouse transgene, Vcan AA, with validated mutations in the GAGß domain that specifically abolish this proteolytic event. Vcan AA/AA mice have partially penetrant hindlimb soft tissue syndactyly. However, Adamts20 inactivation in Vcan AA/AA mice leads to fully penetrant, more severe syndactyly affecting all limbs, suggesting that ADAMTS20 cleavage of versican at other sites or of other substrates is an additional requirement for web regression. Indeed, immunostaining with a neoepitope antibody against a cleavage site in the versican GAGα domain demonstrated reduced staining in the absence of ADAMTS20. Significantly, mice with deletion of Vcan exon 8, encoding the GAGß domain, consistently developed soft tissue syndactyly, whereas mice unable to include exon 7, encoding the GAGα domain in Vcan transcripts, consistently had fully separated digits. These findings suggest that versican is cleaved within each GAG-bearing domain during web regression, and affirms that proteolysis in the GAGß domain, via generation of versikine, has an essential role in interdigital web regression.

Mass spectrometry-based proteomic analysis of parathyroid adenomas reveals PTH as a new human hormone-derived amyloid fibril protein.

BACKGROUND: Congo red-positive material was described in normal and diseased parathyroids (adenoma and hyperplasia) 50 years ago. However, the incidence and the clinical significance of such observation are unknown, and the causal fibril protein has never been convincingly demonstrated. METHODS: We conducted the present study including an exceptional case report accompanied with a retrospective study of 105 parathyroid adenomas. We used histopathological, immunohistochemical, ultrastructural, mass spectrometry-based proteomic analysis of parathyroid adenoma tissue samples, and genetic analysis. RESULTS: We describe a 57-year-old man with mild hypercalcemia and elevated parathyroid hormone (PTH) level for whom histopathological analysis revealed a parathyroid adenoma associated with nodular typical amyloid deposits. Tandem mass spectrometry after laser microdissection (LMD-MS) of amyloid adenoma identified PTH as the fibril protein, and no germline mutation in the PTH gene was detected. Congo red-positive PTH-deposits were further observed in 6.6% of the parathyroid adenomas analyzed, and were associated with complete/incomplete or absent universal amyloid signature, but with fibrillar morphology at ultrastructural level. CONCLUSIONS: Inappropriate PTH production leads to progressive disease-amyloid aggregation of PTH in a subset of parathyroid adenomas, providing new insights into the pathophysiology of this condition and adding PTH to the list of amyloid protein derived from hormones.

Choroidal and peripapillary changes in high myopic eyes with Stickler syndrome.

BACKGROUND: To compare different clinical and Spectral-Domain Optical Coherence Tomography (SD-OCT) features of high myopic eyes with Stickler syndrome (STL) with matched controls. METHODS: Patients with genetically confirmed STL with axial length ≥ 26 mm and controls matched for axial length were included. The following data were obtained from SD-OCT scans and fundus photography: choroidal and retinal thickness (respectively, CT and RT), peripapillary atrophy area (PAA), presence of posterior staphyloma (PS). RESULTS: Twenty-six eyes of 17 patients with STL and 25 eyes of 19 controls were evaluated. Compared with controls, patients with STL showed a greater CT subfoveally, at 1000 µm from the fovea at both nasal and temporal location, and at 2000 and 3000 µm from the fovea in nasal location (respectively, 188.7±72.8 vs 126.0±88.7 µm, 172.5±77.7 vs 119.3±80.6 µm, 190.1±71.9 vs 134.9±79.7 µm, 141.3±56.0 vs 98.1±68.5 µm, and 110.9±51.0 vs 67.6±50.7 µm, always P< 0.05). Furthermore, patients with STL showed a lower prevalence of PS (11.5% vs 68%, P< 0.001) and a lower PAA (2.2±2.1 vs 5.4±5.8 mm2, P=0.03), compared with controls. CONCLUSIONS: This study shows that high myopic patients with STL show a greater CT, a lower PAA and a lower prevalence of PS, compared with controls matched for axial length. These findings could be relevant for the development and progression of myopic maculopathy in patients with STL.

Recent developments in the management of congenital cataract.

Congenital cataract is a rare eye disease, one of the leading treatable causes of low vision in children worldwide. Hereditary cataracts can be divided in syndromic and non-syndromic cataracts. Early diagnosis in congenital cataracts is key to reach good visual function. Current surgical techniques, that combine microincision cataract extraction and primary intraocular lens (IOL) implantation, have improved childhood cataract outcome. Complications include posterior capsule opacification (PCO), aphakic or pseudophakic glaucoma, uveitis, pupil displacement and IOL decentration. A recent study using a modified Delphi approach identified areas of consensus and disagreement in the management of pediatric cataract. A consensus or near consensus was achieved for 79% of the questions, however 21% of the questions remained controversial, as for IOL implantation strategy. Congenital cataracts show a highly variable phenotype and genotype, and can be related to different mutations, genetic variance, and other risk factors. Congenital cataracts can be associated with other ocular developmental abnormalities, including microphthalmia, microcornea, or aniridia and with systemic findings. Next-generation sequencing (NGS) and forthcoming new ultra-high-throughput sequencing represent excellent tools to investigate the genetic causes of congenital cataracts. A better recognition of different clinical presentations and underlying etiologies of congenital cataracts may lead to the development of new approaches to improve visual outcome after cataract surgery and promote early detection of systemic associated syndromes.

Organ Transplantation in Hereditary Fibrinogen A α-Chain Amyloidosis: A Case Series of French Patients.

RATIONALE & OBJECTIVE: Fibrinogen A α-chain amyloidosis (AFib amyloidosis) is a form of amyloidosis resulting from mutations in the fibrinogen A α-chain gene (FGA), causing progressive kidney disease leading to kidney failure. Treatment may include kidney transplantation (KT) or liver-kidney transplantation (LKT), but it is not clear what factors should guide this decision. The aim of this study was to characterize the natural history and long-term outcomes of this disease, with and without organ transplantation, among patients with AFib amyloidosis and various FGA variants. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: 32 patients with AFib amyloidosis diagnosed by genetic testing in France between 1983 and 2014, with a median follow-up of 93 (range, 4-192) months, were included. RESULTS: Median age at diagnosis was 51.5 (range, 12-77) years. Clinical presentation consisted of proteinuria (93%), hypertension (83%), and kidney failure (68%). Manifestations of kidney disease appeared on average at age 57 (range, 36-77) years in patients with the E526V variant, at age 45 (range, 12-59) years in those with the R554L variant (P<0.001), and at age 24.5 (range, 12-31) years in those with frameshift variants (P<0.001). KT was performed in 15 patients and LKT was performed in 4. In KT patients with the E526V variant, recurrence of AFib amyloidosis in the kidney graft was less common than with a non-E526V (R554L or frameshift) variant (22% vs 83%; P=0.03) and led to graft loss less frequently (33% vs 100%). Amyloid recurrence was not observed in patients after LKT. LIMITATIONS: Analyses were based on clinically available historical data. Small number of patients with non-E526V and frameshift variants. CONCLUSIONS: Our study suggests phenotypic variability in the natural history of AFib amyloidosis, depending on the FGA mutation type. KT appears to be a viable option for patients with the most common E526V variant, whereas LKT may be a preferred option for patients with frameshift variants.

New clinical forms of hereditary apoA-I amyloidosis entail both glomerular and retinal amyloidosis.

Apolipoprotein A1 amyloidosis (ApoAI) results from specific mutations in the APOA1 gene causing abnormal accumulation of amyloid fibrils in diverse tissues. The kidney is a prominent target tissue in ApoAI amyloidosis with a remarkable selectivity for the renal medulla. Here, we investigated six French families with ApoAI Glu34Lys, p.His179Profs∗47, and a novel p.Thr185Alafs∗41 variant revealing unprecedented clinical association of a glomerular with a retinal disease. Comprehensive clinicopathological, molecular and proteomics studies of numerous affected tissues ensured the correlation between clinical manifestations, including novel unrecognized phenotypes, and apoA-I amyloid deposition. These ophthalmic manifestations stemmed from apoA-I amyloid deposition, highlighting that the retina is a previously unrecognized tissue affected by ApoAI amyloidosis. Our study provides the first molecular evidence that a significant fraction of ApoAI amyloidosis cases with no family history result from spontaneous neomutations rather than variable disease penetrance. Finally, successful hepatorenal transplantation resulted in a life- and vision-saving measure for a 32-year-old man with a hitherto unreported severe ApoAI amyloidosis caused by the very rare Glu34Lys variant. Our findings reveal new modes of occurrence and expand the clinical spectrum of ApoAI amyloidosis. The awareness of glomerular and ocular manifestations in ApoAI amyloidosis should enable earlier diagnosis and avoid misdiagnosis with other forms of renal amyloidosis. Thus, documented apoA-I amyloid deposition in the retina offers new biological information about this disease and may change organ transplantation practice to reduce retinal damage in patients with ApoAI amyloidosis.

Angiographic Signatures of the Predominant Form of Familial Transthyretin Amyloidosis (Val30Met Mutation).

PURPOSE: To describe abnormalities in choroidal and retinal vasculature associated with Val30Met familial transthyretin amyloidosis (V30M-FTA) using fluorescein and indocyanine green (ICG) angiography. DESIGN: Prospective, cross-sectional study. METHODS: This study was conducted at the French National Reference Center for FTA. We included 18 consecutive genetically confirmed V30M-FTA patients (36 eyes) who underwent complete neurologic examination, including staging with polyneuropathy disability (PND) score, and complete ophthalmic evaluation, including staging of intraocular amyloid deposits and fluorescein and ICG angiograms (ICG-A). The grading of choroidal and retinal angiopathy, and their association with neurologic functional impairment, were the main outcome measures. RESULTS: Eleven men and 7 women, mean age 61.6 ± 12.1 years, were included. Retinal amyloid angiopathy (RAA) was detected in 24 eyes (92%) of 13 patients, with microaneurysms, retinal hemorrhages, and retinal ischemia of variable extent. Three patients (5 eyes) had neovascular glaucoma and 2 (2 eyes) had preretinal neovascularization. ICG-A indicated choroidal amyloid angiopathy (CAA) in all patients, with 3 distinct patterns-diffuse (9/18 patients), focal (5/18 patients), or punctiform (4/18 patients)-based on the extent of late hypercyanescence along the choroidal arteries. PND scores were significantly higher in patients with diffuse CAA (firework pattern) compared to those with limited CAA (focal and punctiform patterns) (2.89 vs 1.78, P = .045). CONCLUSION: RAA is a frequent and severe complication of V30M-FTA that may lead to anterior and posterior segment neovascularization. CAA was detected in all patients, with a late hypercyanescent delineation of the choroidal arterial vasculature, which was more extensive with increased disease severity.

VLITL is a major cross-ß-sheet signal for fibrinogen Aα-chain frameshift variants.

The first case of hereditary fibrinogen Aα-chain amyloidosis was recognized >20 years ago, but disease mechanisms still remain unknown. Here we report detailed clinical and proteomics studies of a French kindred with a novel amyloidogenic fibrinogen Aα-chain frameshift variant, Phe521Leufs, causing a severe familial form of renal amyloidosis. Next, we focused our investigations to elucidate the molecular basis that render this Aα-chain variant amyloidogenic. We show that a 49-mer peptide derived from the C-terminal part of the Phe521Leufs chain is deposited as fibrils in the patient's kidneys, establishing that only a small portion of Phe521Leufs directly contributes to amyloid formation in vivo. In silico analysis indicated that this 49-mer Aα-chain peptide contained a motif (VLITL), with a high intrinsic propensity for ß-aggregation at residues 44 to 48 of human renal fibrils. To experimentally verify the amyloid propensity of VLITL, we generated synthetic Phe521Leufs-derived peptides and compared their capacity for fibril formation in vitro with that of their VLITL-deleted counterparts. We show that VLITL forms typical amyloid fibrils in vitro and is a major signal for cross-ß-sheet self-association of the 49-mer Phe521Leufs peptide identified in vivo, whereas its absence abrogates fibril formation. This study provides compelling evidence that VLITL confers amyloidogenic properties to Aα-chain frameshift variants, yielding a previously unknown molecular basis for the pathogenesis of Aα-chain amyloidosis.

Hereditary lysozyme amyloidosis with sicca syndrome, digestive, arterial, and tracheobronchial involvement: case-based review.

Lysozyme amyloidosis (ALys) is a rare autosomal dominant hereditary systemic amyloidosis associated with a large spectrum of clinical manifestations. ALys phenotype mainly involves the digestive tract, liver and spleen, kidneys, lymph nodes, skin, and lachrymal and salivary glands. Very recently, cardiac involvement and peripheral neuropathy associated with a new p.Leu102Ser variant of lysozyme have been documented. In the present observation, we extend the phenotypic heterogeneity of ALys to the tracheobronchial tree with histologically proven bronchial ALys-amyloid deposits. We report the case of a 62-year-old man of Italian origin (Piedmont) diagnosed with ALys associated with the p.Trp82Arg variant. The patient complained of upper digestive symptoms, sicca syndrome, and lately recurrent pulmonary infections. Thoracic endoscopy revealed a fragile, inflammatory, and granulomatous aspect of the bronchi. Amyloid deposits were observed in the upper digestive tract, salivary glands, temporal artery, and tracheobronchial tree. Symptomatic treatment was offered. Recurrent pulmonary infections occurred during the follow-up. Lung involvement in hereditary ALys has only been exceptionally described. Although vascular involvement has already been reported in ALys in many organs, it never concerned cranial arteries. This case highlights the systemic nature of the amyloid protein variant deposits and expands the spectrum of clinical manifestations to chest involvement. The literature review highlights that hereditary ALys with the p.Trp82Arg variant is frequent in patients coming from Piedmont (Italy). Due to diffuse organs involvement related to ALys, it is important not to misdiagnose ALys for AL amyloidosis, the most frequent form of amyloidosis.

Vitreous amyloidosis with autonomic neuropathy of the digestive tract associated with a novel transthyretin p.Gly87Arg variant in a Bangladeshi patient: a case report.

BACKGROUND: Hereditary transthyretin amyloidosis is an autosomal dominant inherited disorder, first described in families with sensorimotor and autonomic neuropathy. Since its first description, more than 120 amyloidogenic transthyretin mutations have been reported with various geographic distributions and associated with a wide range of phenotypes involving the peripheral nerve, the heart, the gastrointestinal tract, the eyes, the central nervous system, or the kidneys. In some cases of transthyretin amyloidosis, the first clinical manifestation is vitreous opacity. CASE PRESENTATION: A 46-year-old Bangladeshi woman presented with vitreous amyloidosis and progressive autonomic neuropathy of the digestive tract as initial clinical manifestations, with no clinical evidence of cardiac, renal, central nervous system, or peripheral nerve dysfunction. A novel transthyretin mutation, p.Gly87Arg, was identified in the heterozygous state in this proband of Bangladeshi origin. Histological examination of accessory salivary glands and gastric biopsies revealed Congo-red-positive deposits. Laser microdissection of salivary gland Congo-red deposits and tandem mass spectrometry-based proteomic analysis identified the mutated transthyretin peptide containing the arginine residue at position 87 of the mature protein. CONCLUSIONS: Vitreous amyloidosis should be considered a differential diagnosis of uveitis, in particular transthyretin amyloidosis. Proteomics data from our case, consistent with the genetic findings, highly suggests that this new p.Gly87Arg variant is amyloidogenic. Here, we described the second case of transthyretin amyloidosis reported in a Bangladeshi patient.

Deletions Overlapping VCAN Exon 8 Are New Molecular Defects for Wagner Disease.

Wagner disease is a rare nonsyndromic autosomal-dominant vitreoretinopathy, associated with splice mutations specifically targeting VCAN exon 8. We report the extensive genetic analysis of two Wagner probands, previously found negative for disease-associated splice mutations. Next-generation sequencing (NGS), quantitative real-time PCR, and long-range PCR identified two deletions (3.4 and 10.5 kb) removing at least one exon-intron boundary of exon 8, and both correlating with an imbalance of VCAN mRNA isoforms. We showed that the 10.5-kb deletion occurred de novo, causing somatic mosaicism in the proband's mother who had an unusually mild asymmetrical phenotype. Therefore, exon 8 deletions are novel VCAN genetic defects responsible for Wagner disease, and VCAN mosaic mutations may be involved in the pathogenesis of Wagner disease with attenuated phenotype. NGS is then an effective screening tool for genetic diagnosis of Wagner disease, improving the chance of identifying all disease-causative variants as well as mosaic mutations in VCAN.

D25V apolipoprotein C-III variant causes dominant hereditary systemic amyloidosis and confers cardiovascular protective lipoprotein profile.

Apolipoprotein C-III deficiency provides cardiovascular protection, but apolipoprotein C-III is not known to be associated with human amyloidosis. Here we report a form of amyloidosis characterized by renal insufficiency caused by a new apolipoprotein C-III variant, D25V. Despite their uremic state, the D25V-carriers exhibit low triglyceride (TG) and apolipoprotein C-III levels, and low very-low-density lipoprotein (VLDL)/high high-density lipoprotein (HDL) profile. Amyloid fibrils comprise the D25V-variant only, showing that wild-type apolipoprotein C-III does not contribute to amyloid deposition in vivo. The mutation profoundly impacts helical structure stability of D25V-variant, which is remarkably fibrillogenic under physiological conditions in vitro producing typical amyloid fibrils in its lipid-free form. D25V apolipoprotein C-III is a new human amyloidogenic protein and the first conferring cardioprotection even in the unfavourable context of renal failure, extending the evidence for an important cardiovascular protective role of apolipoprotein C-III deficiency. Thus, fibrate therapy, which reduces hepatic APOC3 transcription, may delay amyloid deposition in affected patients.

Spectral-Domain Optical Coherence Tomography in Wagner Syndrome: Characterization of Vitreoretinal Interface and Foveal Changes.

PURPOSE: To evaluate the spectrum of morphologic abnormalities in patients with Wagner syndrome by spectral-domain optical coherence tomography (SD OCT). DESIGN: Retrospective comparative case study. METHODS: Institutional study of patients entered into the French Vitreoretinopathy Study Group database. Twelve eyes of 9 patients from 3 unrelated families with genetically confirmed Wagner syndrome and 28 eyes from 15 age- and sex-matched healthy family controls were scanned by SD OCT. Morphology and layer thickness of the total retina, inner retinal layers, outer retinal layers, and photoreceptor layer at different degrees of eccentricity from the fovea were compared between the 2 groups. RESULTS: A thick multilayered membrane adherent to the perifovea but completely detached from the fovea, thus forming a bridge over the foveal pit, was observed in 84% of eyes from patients with Wagner syndrome. At the equatorial area, SD OCT imaging allowed visualization of the architecture of an avascular vitreous veil with localized retinal traction. Most retinal layers were significantly thinner in patients with Wagner syndrome compared to the control group, except at the foveal center where abnormal persistence of 1 or more inner retinal layers could be observed. CONCLUSION: SD OCT provides better structural insight into the range of retinal defects at the vitreoretinal interface and fovea, which is not only useful for improving diagnosis and management, but also for understanding the pathogenesis of Wagner syndrome.

Distinctive Patterns of Transthyretin Amyloid in Salivary Tissue: A Clinicopathologic Study of 92 Patients With Amyloid-containing Minor Salivary Gland Biopsies.

Accurate typing of amyloidosis is still a major issue for pathologists and clinicians. Besides clinical data and immunohistochemistry, the histologic distribution of amyloid could represent a useful tool to prevent typing errors, such as the misdiagnosis of hereditary and senile amyloidosis as light chain-related amyloidosis (AL). Minor salivary gland biopsy (MSGB) is a widely performed procedure for amyloidosis diagnosis and typing. In the largest clinicopathologic series of amyloid-containing MSGB specimens to date, we investigated for the first time whether amyloidosis subtypes can be distinguished according to their pattern of salivary amyloid deposition. The histologic distribution and semiquantification of amyloid within salivary tissue were thoroughly reassessed for each case using Congo red-fluorescence. Clinical data were retrospectively collected. The cohort included 92 patients with amyloid-containing minor salivary gland biopsies. The type of amyloidosis was AL in 51 patients (55.4%), non-V30M mutant ATTR in 10 (10.9%), V30M mutant ATTR in 8 (8.7%), serum amyloid A-derived amyloidosis (AA) in 6 (6.5%), wild-type ATTR in 4 (4.3%), gelsolin in 3 (3.3%), and unclassified in 10 (10.9%). Amyloid was more abundant in AL and AA compared with ATTR amyloidosis, because of more extensive basement membranes and vascular deposits. Conversely, non-V30M mutant ATTR and wt-ATTR were strongly associated with peculiar amyloid nodules located in close contact with salivary excretory ducts, with a specificity of 91.7%. In conclusion, our study suggests for the first time that MSGB, in addition to its high sensitivity for amyloidosis diagnosis, is a simple and effective tool for the recognition of ATTR amyloidosis.