Penetrating Keratoplasty for Corneal Amyloidosis in Familial Amyloidosis, Finnish Type

Exploring clinical variability in gelsolin amyloidosis: Brazilian family case study with confocal microscopy

INTRODUCTION

Genetic mutations or inflammatory, degenerative, or neoplastic conditions can trigger amyloidosis. Hereditary gelsolin amyloidosis is a genetic disorder primarily marked by amyloid fibrils composed of misfolded gelsolin fragments.

CASE REPORT

We present three sisters with AGel amyloidosis, illustrating its clinical diversity. Patient 1, a 51-year-old, had bilateral ptosis, ocular discomfort, and dry eye syndrome due to cranial nerve involvement. Patient 2, a 53-year-old, experienced progressive bilateral visual impairment. Patient 3, a 50-year-old, exhibited right eye ectropion. Genetic analysis, with the identical mutation, heterozygous c.640G > A (p.Asp214Asn) mutation, confirmed AGel amyloidosis diagnoses, with common findings including lattice corneal amyloidosis, reduced corneal sensitivity, and recurrent corneal erosions. Neurological manifestations included ataxia and peripheral neuropathy, with skin abnormalities observed in patient 1. Ocular involvement severity and distribution varied among patients.

DISCUSSION

Common ocular and neurological manifestations validated AGel amyloidosis diagnoses, reinforcing its hereditary basis. Neurological symptoms highlighted the disorder's impact on various organ systems, while skin abnormalities contributed to ocular discomfort. Variable ocular involvement emphasized the disorder's heterogeneity. These patients emphasize hereditary gelsolin amyloidosis's clinical diversity and suggest potential environmental influences on disease expression. Genetic confirmation and confocal microscopy findings reaffirm the genetic basis while raising questions about assessing systemic disease severity, necessitating further investigation in larger cohorts. Ophthalmologists' specialized care is crucial for managing ocular symptoms, given the absence of a universal cure.

IC3D Classification of Corneal Dystrophies-Edition 3

PURPOSE

The International Committee for the Classification of Corneal Dystrophies (IC3D) was created in 2005 to develop a new classification system integrating current information on phenotype, histopathology, and genetic analysis. This update is the third edition of the IC3D nomenclature.

METHODS

Peer-reviewed publications from 2014 to 2023 were evaluated. The new information was used to update the anatomic classification and each of the 22 standardized templates including the level of evidence for being a corneal dystrophy [from category 1 (most evidence) to category 4 (least evidence)].

RESULTS

Epithelial recurrent erosion dystrophies now include epithelial recurrent erosion dystrophy, category 1 ( COL17A1 mutations, chromosome 10). Signs and symptoms are similar to Franceschetti corneal dystrophy, dystrophia Smolandiensis, and dystrophia Helsinglandica, category 4. Lisch epithelial corneal dystrophy, previously reported as X-linked, has been discovered to be autosomal dominant ( MCOLN1 mutations, chromosome 19). Classic lattice corneal dystrophy (LCD) results from TGFBI R124C mutation. The LCD variant group has over 80 dystrophies with non-R124C TGFBI mutations, amyloid deposition, and often similar phenotypes to classic LCD. We propose a new nomenclature for specific LCD pathogenic variants by appending the mutation using 1-letter amino acid abbreviations to LCD. Pre-Descemet corneal dystrophies include category 1, autosomal dominant, punctiform and polychromatic pre-Descemet corneal dystrophy (PPPCD) ( PRDX3 mutations, chromosome 10). Typically asymptomatic, it can be distinguished phenotypically from pre-Descemet corneal dystrophy, category 4. We include a corneal dystrophy management table.

CONCLUSIONS

The IC3D third edition provides a current summary of corneal dystrophy information. The article is available online at https://corneasociety.org/publications/ic3d .

Clinical and Histopathologic Characteristics and Template of the TGFBI p.(His626Arg) Missense Variant Lattice Corneal Dystrophy

PURPOSE

The aim of this study was to define, following the IC3D template format, the clinical and histopathologic phenotype of the p.(His626Arg) missense variant lattice corneal dystrophy (LCDV-H626R), the most common variant lattice dystrophy, and to record long-term outcome of corneal transplantation in this dystrophy.

METHODS

A database search and a meta-analysis of published data on LCDV-H626R were conducted. A patient diagnosed with LCDV-H626R who underwent bilateral lamellar keratoplasty followed by rekeratoplasty of 1 eye is described, including histopathologic examination of the 3 keratoplasty specimens.

RESULTS

One hundred forty-five patients from at least 61 families and 11 countries diagnosed with LCDV-H626R were found. This dystrophy is characterized by recurrent erosions, asymmetric progression, and thick lattice lines that extend to corneal periphery. The median age is 37 (range, 25-59) years at the onset of symptoms, 45 (range, 26-62) years at the time of diagnosis, and 50 (range, 41-78) years at the time of the first keratoplasty, suggesting a median interval from the first symptoms to diagnosis and to keratoplasty of 7 and 12 years, respectively. Clinically unaffected carriers have been of age 6 to 45 years. Central anterior stromal haze and centrally thick, peripherally thinner branching lattice lines in the anterior to midstroma of the cornea were noted preoperatively. Histopathology of the host anterior corneal lamella showed a subepithelial fibrous pannus, a destroyed Bowman layer, and amyloid deposits extending to the deep stroma. In the rekeratoplasty specimen, amyloid localized to scarring along the Bowman membrane and to the margins of the graft.

CONCLUSIONS

The IC3D-type template for LCDV-H626R should help diagnose and manage variant carriers. The histopathologic spectrum of findings is broader and more nuanced than what has been reported.

Update on the Corneal Dystrophies-Genetic Testing and Therapy

ABSTRACT

One major purpose of the IC3D Corneal Dystrophy Nomenclature Revision was to include genetic information with a goal of facilitating investigation into the pathogenesis, treatment, and perhaps even prevention of the corneal dystrophies, an ambitious goal. Over a decade has passed since the first publication of the IC3D Corneal Dystrophy Nomenclature Revision. Gene therapy is available for an early-onset form of inherited retinal degeneration called Leber congenital amaurosis, but not yet for corneal degenerations. We review the current state of affairs regarding our original ambitious goal. We discuss genetic testing, gene therapy [RNA interference (RNAi) and genome editing], and ocular delivery of corneal gene therapy for the corneal dystrophies. Why have gene therapy techniques not yet been introduced for the corneal dystrophies?

A novel missense TGFBI variant p.(Ser591Phe) in a Finnish family with variant lattice corneal dystrophy

INTRODUCTION

We describe the phenotype of a variant lattice corneal dystrophy (LCD) potentially caused by a novel variant c.1772C>T p.(Ser591Phe) in exon 13 of the transforming growth factor beta-induced (TGFBI) gene.

CASE REPORT

The proband, a 71-year-old woman referred because of bilateral LCD, first seen at the age of 65 years, with recent progressive symptoms, underwent a clinical ophthalmological examination, anterior segment optical coherence tomography and confocal microscopy. Additionally, three siblings and three children were examined. The identified TGFBI variant was screened in six family members using Sanger sequencing. A corneal dystrophy gene screen was performed for the proband. Translucent subepithelial irregularities and central to midperipheral stubby branching corneal stromal lattice lines, asymmetric between the right and the left eye, were visible and resulted in mild deterioration of vision in one eye. Genetic testing revealed a novel variant c.1772C>T in TGFBI, leading to the amino acid change p.(Ser591Phe). One daughter carried the same variant but had only thick stromal nerve fibres at the age of 49 years. The other family members neither had corneal abnormalities nor carried the variant. No keratoplasty is yet planned for the proband.

CONCLUSIONS

We classify the novel variant in TGFBI as possibly pathogenic, potentially causing the late-onset, asymmetric variant LCD. Our findings add to the growing number of TGFBI variants associated with a spectrum of phenotypes of variant LCD.

Contact lens induced bacterial keratitis in LCD II: Management and multimodal imaging: a case report and review of literature

PURPOSE

To describe the management and multimodal imaging of lattice corneal dystrophy type II (LCD-II) complicated by an infectious keratitis due to a bandage contact lens and to review current literature.

OBSERVATION

A 50-year-old female was diagnosed with Meretoja's Syndrome by the triad of facial palsy, loose skin (cutix laxa), and stromal corneal dystrophy. At slit lamp, bilateral lattice corneal dystrophy (LCD) was characterized by multiple linear refractile lines and subepithelial fibrosis along with Neurotrophic keratitis Mackie grade I. Findings of anterior segment optical coherence tomography (AS-OCT) were epithelial irregularity, subepithelial fibrosis, hyperreflectivity on anterior stromal layer, lobulated stromal surface. In vivo confocal microscopy (IVCM) showed hyperreflected deposits on the basal and Bowman layers, visible keratocytes; fine lines and streaks between corneal lamella. The sub-basal nerve plexus and the stromal nerves were no longer visible. She presented in emergency with a left red eye. A severe bacterial keratitis was diagnosed as a complication of a bandage contact lens used to treat recurrent epithelial erosion. Corneal anesthesia was complete. Corneal neovascularization was evident 10 weeks later and topical bevacizumab (5 mg/ml) was introduced twice daily. Partial regression of deep stromal vessels was noticed at 3 months.

CONCLUSION

In Meretoja's syndrome, neurotrophic keratopathy secondary to polyneuropathy due to systemic amyloid deposits is present in the advanced stages, promotes recurrent corneal erosions. Corneal sensitivity test, AS-OCT and IVCM are crucial in the diagnosis behind any recurrent corneal erosion. The use of bandage contact lens should be avoided in Meretoja's syndrome to prevent a possible infectious keratitis.

Amyloidosis and Ocular Involvement: an Overview

Purpose: To describe the ophthalmic manifestations of amyloidosis and the corresponding therapeutic measures.Methods: The 178 patients included in the study had different types of amyloidosis, diagnosed at a single internal medicine institution (Bari, Italy). To provide a comprehensive review of the types of amyloidosis that can be associated with ocular involvement, the images and clinical descriptions of patients with amyloidosis structurally related to gelsolin, keratoepithelin and lactoferrin were obtained in collaborations with the ophthalmology departments of hospitals in Mainz (Germany) and Helsinki (Finland).Results: Overall, ocular morbidity was detected in 41 of the 178 patients with amyloidosis (23%). AL amyloidosis was diagnosed in 18 patients with systemic disease, 3 with multiple myeloma, and 11 with localized amyloidosis. AA amyloidosis was detected in 2 patients with rheumatoid arthritis and 3 with Behçet syndrome, and transthyretin amyloidosis in 4 patients. The treatment of AL amyloidosis is based on chemotherapy to suppress the production of amyloidogenic L-chains and on surgical excision of orbital or conjunctival masses. AA amyloidosis is managed by targeting the underlying condition. Vitreous opacities and additional findings of ocular involvement in patients with transthyretin amyloidosis indicate the need for pars plana vitrectomy. Gelsolin amyloidosis, characterized by lattice corneal amyloidosis and polyneuropathy, results in recurrent keratitis and corneal scarring, such that keratoplasty is inevitable. In patients with lattice corneal dystrophies associated with amyloid deposits of keratoepithelin fragments, corneal transparency is compromised by deposits of congophilic material in the subepithelial layer and deep corneal stroma. Patients with established corneal opacities are treated by corneal transplantation, but the prognosis is poor because recurrent corneal deposits are possible after surgery. In patients with gelatinous drop-like dystrophy, the amyloid fibrils that accumulate beneath the corneal epithelium consist of lactoferrin and can severely impair visual acuity. Keratoplasty and its variants are performed for visual rehabilitation.Conclusion: A routine ophthalmic follow-up is recommended for all patients with established or suspected amyloidosis, independent of the biochemical type of the amyloid. Close collaboration between the ophthalmologist and the internist will facilitate a more precise diagnosis of ocular involvement in amyloidosis and allow the multidisciplinary management of these patients.Abbreviations: CD: corneal dystrophy; CLA: corneal lattice amyloidosis; CNS: central nervous system; CT: computed tomography; FAP: familial amyloidotic polyneuropathy; GDLCD: gelatinous drop-like corneal dystrophy; GLN: gelsolin; LCD: lattice corneal dystrophy; MRI: magnetic resonance imaging; OLT: orthotopic liver transplantation; TEM: transmission electron microscopy; TGFBI: transforming growth factor β induced; TTR: transthyretin.

Deep Learning Algorithms for Corneal Amyloid Deposition Quantitation in Familial Amyloidosis

Objectives

The aim of this study was to train and validate deep learning algorithms to quantitate relative amyloid deposition (RAD; mean amyloid deposited area per stromal area) in corneal sections from patients with familial amyloidosis, Finnish (FAF), and assess its relationship with visual acuity.

Methods

Corneal specimens were obtained from 42 patients undergoing penetrating keratoplasty, stained with Congo red, and digitally scanned. Areas of amyloid deposits and areas of stromal tissue were labeled on a pixel level for training and validation. The algorithms were used to quantify RAD in each cornea, and the association of RAD with visual acuity was assessed.

Results

In the validation of the amyloid area classification, sensitivity was 86%, specificity 92%, and F-score 81. For corneal stromal area classification, sensitivity was 74%, specificity 82%, and F-score 73. There was insufficient evidence to demonstrate correlation (Spearman's rank correlation, -0.264, p = 0.091) between RAD and visual acuity (logMAR).

Conclusions

Deep learning algorithms can achieve a high sensitivity and specificity in pixel-level classification of amyloid and corneal stromal area. Further modeling and development of algorithms to assess earlier stages of deposition from clinical images is necessary to better assess the correlation between amyloid deposition and visual acuity. The method might be applied to corneal dystrophies as well.

The First Argentinian Family with Familial Amyloidosis of the Finnish Type

Familial amyloidosis of the Finnish type or Meretoja syndrome is a rare autosomic dominant inherited systemic condition. It was first described by Meretoja in Finland in 1969. It is a disease produced by a single mutation in the gene coding for gelsolin, which generates an abnormal protein that cumulates in tissues and leads to various signs. Obtaining an early diagnosis can be challenging, as the first manifestations of the disease are ophthalmological and may only be seen with slit-lamp biomicroscopy. We present the first 3 cases diagnosed in Argentina, confirmed by genetic molecular testing.

Gelsolin amyloid angiopathy causes severe disruption of the arterial wall

Hereditary gelsolin amyloidosis (HGA) is a dominantly inherited systemic disease reported worldwide. HGA is characterized by ophthalmological, neurological, and dermatological manifestations. AGel amyloid accumulates at basal lamina of epithelial and muscle cells, thus amyloid angiopathy is encountered in nearly every organ. HGA patients have cardiovascular, hemorrhagic, and potentially vascularly induced neurological problems. To clarify pathomechanisms of AGel angiopathy, we performed histological, immunohistochemical, and electron microscopic analyses on facial temporal artery branches from 8 HGA patients and 13 control subjects. We demonstrate major pathological changes in arteries: disruption of the tunica media, disorganization of vascular smooth muscle cells, and accumulation of AGel fibrils in arterial walls, where they associate with the lamina elastica interna, which becomes fragmented and diminished. We also provide evidence of abnormal accumulation and localization of collagen types I and III and an increase of collagen type I degradation product in the tunica media. Vascular smooth muscle cells appear to be morphologically and semi-quantitatively normal, only their basal lamina is often thickened. In conclusion, angiopathy in HGA results in severe disruption of arterial walls, characterized by prominent AGel deposition, collagen derangement and severe elastolysis, and it may be responsible for several, particularly hemorrhagic, disease manifestations in HGA.

Gender differences in the clinical course of Finnish gelsolin amyloidosis

PURPOSE

To investigate gender differences in Finnish gelsolin amyloidosis (AGel amyloidosis).

PATIENTS AND METHODS

AGel amyloidosis patients, who were members of Finnish Amyloidosis Association (SAMY), filled in a questionnaire compiling known and suspected aspects of their disease. Telephone interviews and hospital medical records, when available, complemented the questionnaire. The data were entered to the database in order to create a national AGel amyloidosis patient registry (FIN-GAR).

RESULTS

A total of 227 patients, 156 women and 71 men, participated in the study. The women in our registry noticed their first symptoms at the median age of 39 years versus 43 years for men (p = 0.01). At the age in which the diagnosis was made there was a trend to be observed between men and women (women: 39 years versus men: 43 years, p = 0.053). Corneal lattice dystrophy was diagnosed in significantly younger women than men (median ages 41 versus 49 years, respectively, p = 0.01). Of other ophthalmological manifestations, corneal ulcer, impaired vision and glaucoma were all diagnosed at least 5 years earlier in women, although differences were not statistically significant. Ophthalmological manifestations, such as dry eyes and corneal ulcer; dermatological signs, such as blepharochalasis, and also neurological symptoms, such as myokymia and carpal tunnel syndrome, were more prevalent among women.

CONCLUSIONS

In the largest so far available study on AGel amyloidosis we show that women developed symptoms and signs of AGel amyloidosis at younger age. Especially eye-related problems occurred earlier and together with nerve and skin manifestations, the characteristic clinical triad in AGel amyloidosis, were more common in women. However, a clear limitation of our study was a selection bias caused by a significant underrepresentation of men in the study population.

Secondary corneal amyloidosis after perforating corneal trauma: A series of 5 cases and review of the literature

We retrospectively reviewed the clinical and surgical histories of 5 patients with traumatic secondary corneal amyloidosis, a relatively rare sequela of nonsurgical and surgical perforating corneal trauma. Four had history of nonsurgical trauma, and 1 had surgical trauma to the cornea. Three specimens were obtained by penetrating keratoplasties and 2 by excision of the cornea during evisceration of the ocular contents. All the corneal specimens showed full-thickness scars of a prior perforating wound with congophilic amyloid deposits that exhibited apple-green birefringence under polarized light and dichroism. All cases had variable degrees of predominantly chronic nongranulomatous inflammation. Ultrastructural examination in 1 patient disclosed 8-nm diameter fibrils in disarray, consistent with amyloid. Amyloid P immunostaining was positive in all 3 patients tested for this protein.

Natural course of Finnish gelsolin amyloidosis

BACKGROUND

Finnish type of hereditary gelsolin amyloidosis (FGA) is one of the most common diseases of Finnish disease heritage. Existing FGA knowledge is based only on smaller patient series, so our aim was to elucidate the natural course of the disease in a comprehensive sample of patients and to build up a national FGA patient registry.

METHODS

An inquiry about the known and suspected signs of FGA, sent to the members of Finnish Amyloidosis Association, telephone contacts, and hospital records were utilized to create the registry.

RESULTS

A total of 227 patients were entered to the database. The first symptom was ophthalmological for 167 patients (73.6%) at the mean age of 39 years. Corneal lattice dystrophy (CLD) was reported at the mean age of 43 years. Impaired vision, polyneuropathy, facial nerve paresis, and cutis laxa appeared on average between 52 and 57 years. Carpal tunnel syndrome (CTS) was reported by 86 patients (37.9%). Nine patients (4.0%) had a pacemaker, and 12 (6.1%) had cardiomyopathy.

CONCLUSIONS

The first symptom was ophthalmological in most cases. Except for CLD no prominent difference in the age of appearance was found between the major symptoms. CTS, cardiac pacemakers, and cardiomyopathy were remarkably more common compared to the general population.