Severe ataxia with neuropathy in hereditary gelsolin amyloidosis: a case report

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.

Familial amyloidosis of the Finnish type: clinical and neurophysiological features of two index cases

Familial amyloidosis of the Finnish type (FAF) is a rare multisystemic disorder caused by mutations in the gelsolin gene. The clinical presentation is typically characterised by a triad of ophthalmic, neurological and dermatological findings. FAF has been reported in several countries, primarily in Finland and recently in Portugal. We report the first genetically confirmed cases of FAF from two unrelated families in our neuromuscular outpatient clinic. Gelsolin gene sequencing revealed the heterozygous gelsolin mutation (c.640G>A). The clinical features and the neurophysiological studies of two index patients and their relatives are presented. Obtaining an early diagnosis can be challenging, but FAF should be considered in the differential diagnosis of progressive bilateral facial neuropathy, even if there is no known Finnish ancestor.

Review of proteomics approach to eye diseases affecting the anterior segment

Visual impairment and blindness is a major health burden worldwide, and major ocular diseases causing visual impairment pertain to the anterior segment of the eye. Anterior segment ocular diseases are common, yet complex entities. Although many treatment options and surgical techniques are available for these ailments, the underlying cause and pathogenesis is still unclear. Finding ways to fundamentally treat these patients and rectify the underlying dysregulations leading to the disease may help cure patients completely without major complications. Proteomics approaches are a novel way to distinguish dysregulated proteins in a variety of biological tissues in a hypothesis-free manner, thus helping to find the responsible pathways leading to a certain disease. The aim of the current study is to review the available knowledge in scientific literature regarding the proteomics studies done on anterior segment eye diseases and suggest potential clinical implications to exploit the results of these studies. SIGNIFICANCE: Anterior segment ocular diseases are responsible for a major proportion of visual impairment and blindness worldwide. Although ophthalmologists have several treatment options that can alleviate or control the progression of these diseases, no definite cure is available for most of them. Moreover, because these diseases are progressive, prompt diagnosis is of utmost important. Proteomics studies enable us to identify and quantify the dysregulated proteins in a biological specimen in a hypothesis-free manner. Understanding the dysregulated protein pathways shines a light on the pathogenesis of the disease. Moreover, these dysregulated proteins may act as biomarkers to help in diagnosis and treatment follow-up. Hence, in this article we sought out to review the available scientific literature regarding the proteomics studies of anterior segment ocular diseases and to identify potential applications of proteomic studies in clinic.

The First Korean Family With Hereditary Gelsolin Amyloidosis Caused by p.D214Y Mutation in the GSN Gene

Hereditary gelsolin amyloidosis (HGA) is an autosomal dominant hereditary disease characterized by corneal lattice dystrophy, peripheral neuropathy, and cutis laxa. So far, no Korean patients with HGA have been reported. A 58-yr-old man presented with involuntary facial twitching, progressive bilateral facial weakness, and tongue atrophy. His mother, maternal uncle, two sisters, and son suffered from the same symptoms. Electrophysiological studies revealed signs of chronic denervation in the cervical and lumbar regions, mild sympathetic autonomic dysfunction, and bilateral facial nerve dysfunction. Diagnostic whole-exome sequencing (WES) revealed a p.D214Y heterozygous mutation in the gelsolin gene in affected members. We present the first report of a Korean family with HGA diagnosed by WES. WES facilitated a clinical diagnosis of HGA in patients with undiagnosed neuropathies.

Increasing amount of amyloid are associated with the severity of clinical features in hereditary gelsolin (AGel) amyloidosis

BACKGROUND

Patients with hereditary gelsolin (AGel) amyloidosis (HGA) present with hanging skin (cutis laxa) and bilateral cranial neuropathy, and require symptomatic plastic surgery. Our clinical observation of tissue fragility prompted us to design a prospective study.

METHODS

Twenty-nine patients with HGA undergoing surgery were interviewed and clinically examined. The height and thickness of skin folds in standard anatomical localizations were measured. The presence and distribution of amyloid in skin samples were analyzed using Congo red staining and immunohistochemistry using antibodies against gelsolin amyloid (AGel) subunit.

RESULTS

The measured skin folds stretched more in patients with HGA (e.g. skin over olecranon, p < 0.001). The skin folds were thinner in patients with HGA (e.g. forehead skin, p < 0.001). The skin and subcutaneous fat were abnormally fragile during surgery. The total amount of AGel amyloid, and its presence in the deep layers of the skin and subcutaneous fat correlated with the measurements of skin folds, age and extent of cranial neuropathy.

CONCLUSIONS

The AGel amyloid in the skin and subcutis, together with morphologic changes in the dermal stroma and skin adnexa contribute to the atrophied and fragile structure of HGA skin. This is the first study to demonstrate the correlation between AGel amyloid accumulation and clinical disease severity.

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.

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.

Relation of gelsolin amyloidosis and periodontal health

OBJECTIVE

Hereditary gelsolin amyloidosis (AGel amyloidosis) is a rare, dominantly inherited systemic disease with worldwide distribution, caused by a gelsolin gene mutation. We studied the periodontal conditions and microbiological plaque composition of AGel amyloidosis patients.

MATERIAL AND METHODS

A voluntary study group of 36 AGel amyloidosis patients (mean age 61) filled in a questionnaire. A thorough periodontal examination included periodontal pocket depth and attachment level measurements, registrations of visible plaque, bleeding on probing and panoramic radiographs. The presence of oral Candida was studied by fungal culture method. Bacterial samples from deepened pockets (≥4 mm) were analyzed with checkerboard DNA-DNA hybridization method.

RESULTS

VPI (15.3 %) and BOP (11.2 %) of the patients were modest reflecting relatively adequate oral self-care. Still 89 % of the patients had at least one PPD of ≥4 mm; 78.5 % of the PPDs ≥6 mm were found in molars. Patients had lost one third of the molars due to periodontitis and/or tooth decay. Half of the patients (53 %) were Candida carriers. Bacterial analysis of subgingival plaque samples revealed bacterial species common to chronic periodontitis.

CONCLUSION

AGel amyloidosis may increase the risk for periodontitis even when the oral self-care is adequate. Molar teeth appear to be mostly affected, leading to tooth loss.

CLINICAL RELEVANCE

AGel amyloidosis as a systemic disease is related with a vast variety of symptoms with variable severity. Even though a causal relationship of the systemic disease and periodontitis has not yet been proven, increased risk for periodontal problems should be considered when examining AGel amyloidosis patients.

Xerostomia in hereditary gelsolin amyloidosis

Hereditary gelsolin amyloidosis (AGel amyloidosis) is a rare, dominantly inherited systemic disease with worldwide distribution, caused by c.654G > A or c.654G > T gelsolin gene mutation. The disease mainly manifests with late-onset dystrophy of the cornea, laxity of the skin and dysfunction of the cranial nerves whereas the oral manifestations have remained less-studied. To examine if AGel amyloidosis also affects salivary gland function, we studied 27 patients. In a questionnaire, 89% of them reported oral dryness, and 74% oral and ocular dryness. Unstimulated (UWS) and stimulated whole salivary flow (SWS) rates were measured, and salivary proteins were analyzed in the patients and controls. Hyposalivation according to UWS was detected in 67% of the patients, while decreased SWS occurred in 63% of the patients and 19% of the controls (p = 0.001). The secretion rates of salivary total protein and IgA were significantly lower in patients than controls. Histopathological analyses of labial salivary gland biopsies showed deposition of gelsolin amyloid, atrophy and inflammation. This study showed that AGel amyloidosis belongs to the differential diagnostic choices to be kept in mind in the patients presenting with xerostomia, low secretion rates of salivary total protein and IgA and/or deposition of amyloid in the minor salivary glands. AGel amyloidosis patients should be advised for efficient dental care.

Hereditary gelsolin amyloidosis

Hereditary gelsolin amyloidosis (HGA) is an autosomally dominantly inherited form of systemic amyloidosis, characterized mainly by cranial and sensory peripheral neuropathy, corneal lattice dystrophy, and cutis laxa. HGA, originally reported from Finland and now increasingly from other countries in Europe, North and South America, and Asia, may still be underdiagnosed worldwide. It is the first and so-far only known disorder caused by a gelsolin gene defect, namely a G654A or G654T mutation. Gelsolin is a principal actin-modulating protein, implicated in multiple biological processes, also in the nervous system, e.g. axonal transport, myelination, neurite outgrowth, and neuroprotection. The gelsolin gene defect causes expression of variant gelsolin, followed by systemic deposition of gelsolin amyloid (AGel) in HGA patients and even other consequences on the metabolism and function of gelsolin. In HGA, specific therapy is not yet available but correct diagnosis enables adequate symptomatic treatment which decisively improves the quality of life in these patients. A transgenic murine model of HGA expressing AGel is available, in anticipation of new treatment options targeted toward this slowly progressive but devastating amyloidosis. Present and future lessons learned from HGA may be applicable even in diagnosis and treatment of other hereditary and sporadic amyloidoses.

Familial amyloidotic polyneuropathy type IV--gelsolin amyloidosis

Familial amyloidotic polyneuropathy type IV, or Gelsolin amyloidosis (GA), is a rare condition caused by G654A or G654T mutation in gelsolin gene at 9q32-34. Gelsolin seems essential in many processes, including inflammation, cell motility, neural recovery, apoptosis and even carcinogenesis. So far reported from many European countries, USA, Japan, Iran and Brazil, GA is probably still underdiagnosed. The typical diagnostic triad includes corneal lattice dystrophy, progressive bilateral facial paralysis and cutis laxa. Patients present with progressive cranial and peripheral neuropathy, eye symptoms, usually mild proteinuria, and cardiac conductive disturbances with age. Central nervous system symptoms are rare. Gelsolin amyloid collection in tissues is widespread. To date, treatment is symptomatic. Regular check-ups with ophthalmologist are recommended. Plastic surgery relieves the functional symptoms caused by facial paralysis and loose, hanging facial skin.

Clinical features and haplotype analysis of newly identified Japanese patients with gelsolin-related familial amyloidosis of Finnish type

Familial amyloidosis of the Finnish type (FAF) is an autosomal dominant form of systematic amyloidosis characterized by lattice corneal dystrophy, cranial neuropathy, and cutis laxa. Although FAF has been frequently found in the Finnish population, FAF is a considerably rare disorder in other regions. In this study, we examined the clinical characteristics as well as the haplotypes of six Japanese patients with FAF from five families. They showed the typical clinical presentations of FAF, but we found a broad range of ages at onset of neurological symptoms. All members had the c.654G>A mutation in GSN. To evaluate the disease haplotypes, high-density single-nucleotide polymorphism (SNP) arrays were used and disease-relevant haplotypes were reconstructed. Haplotype analysis in the four apparently unrelated families suggested a common founder haplotype. In a sporadic FAF patient, however, the haplotype was dissimilar to the founder haplotype. The present study demonstrated that a founder mutation in most of the Japanese families with FAF, except for a sporadic patient in whom a de novo mutation event was suggested as the origin of the mutation.

Gelsolin amyloidosis: genetics, biochemistry, pathology and possible strategies for therapeutic intervention

Protein misassembly into aggregate structures, including cross-β-sheet amyloid fibrils, is linked to diseases characterized by the degeneration of post-mitotic tissue. While amyloid fibril deposition in the extracellular space certainly disrupts cellular and tissue architecture late in the course of amyloid diseases, strong genetic, pathological and pharmacologic evidence suggests that the process of amyloid fibril formation itself, known as amyloidogenesis, likely causes these maladies. It seems that the formation of oligomeric aggregates during the amyloidogenesis process causes the proteotoxicity and cytotoxicity characteristic of these disorders. Herein, we review what is known about the genetics, biochemistry and pathology of familial amyloidosis of Finnish type (FAF) or gelsolin amyloidosis. Briefly, autosomal dominant D187N or D187Y mutations compromise Ca(2+) binding in domain 2 of gelsolin, allowing domain 2 to sample unfolded conformations. When domain 2 is unfolded, gelsolin is subject to aberrant furin endoproteolysis as it passes through the Golgi on its way to the extracellular space. The resulting C-terminal 68 kDa fragment (C68) is susceptible to extracellular endoproteolytic events, possibly mediated by a matrix metalloprotease, affording 8 and 5 kDa amyloidogenic fragments of gelsolin. These amyloidogenic fragments deposit systemically, causing a variety of symptoms including corneal lattice dystrophy and neurodegeneration. The first murine model of the disease recapitulates the aberrant processing of mutant plasma gelsolin, amyloid deposition, and the degenerative phenotype. We use what we have learned from our biochemical studies, as well as insight from mouse and human pathology to propose therapeutic strategies that may halt the progression of FAF.

Familial amyloid polyneuropathy

Familial amyloid polyneuropathies (FAPs) are a group of life-threatening multisystem disorders transmitted as an autosomal dominant trait. Nerve lesions are induced by deposits of amyloid fibrils, most commonly due to mutated transthyretin (TTR). Less often the precursor of amyloidosis is mutant apolipoprotein A-1 or gelsolin. The first identified cause of FAP-the TTR Val30Met mutation-is still the most common of more than 100 amyloidogenic point mutations identified worldwide. The penetrance and age at onset of FAP among people carrying the same mutation vary between countries. The symptomatology and clinical course of FAP can be highly variable. TTR FAP typically causes a nerve length-dependent polyneuropathy that starts in the feet with loss of temperature and pain sensations, along with life-threatening autonomic dysfunction leading to cachexia and death within 10 years on average. TTR is synthesised mainly in the liver, and liver transplantation seems to have a favourable effect on the course of neuropathy, but not on cardiac or eye lesions. Oral administration of tafamidis meglumine, which prevents misfolding and deposition of mutated TTR, is under evaluation in patients with TTR FAP. In future, patients with FAP might benefit from gene therapy; however, genetic counselling is recommended for the prevention of all types of FAP.

The neuromuscular manifestations of amyloidosis

Amyloidosis is a systemic disease that may be acquired or hereditary and which results in the deposition of amyloid fibrils in a variety of tissues causing their progressive dysfunction. Although the clinical presentation often is dominated by cardiac or renal failure, peripheral neuropathy may be a significant or the initial manifestation, resulting in presentation to the neurologist. Diagnosis often is challenging and may require multiple diagnostic procedures, including more than one biopsy. Acquired and hereditary amyloidosis can be definitively distinguished from one another only by immunohistochemical staining or molecular genetic testing. Treatment remains a challenge, although chemotherapy and autologous stem cell transplantation offer hope for those with primary systemic amyloidosis, whereas liver transplantation is effective for some forms of hereditary amyloid neuropathy. Much less commonly, myopathy may be a clinically significant manifestation of amyloidosis.

Lattice corneal dystrophy, gelsolin type (Meretoja's syndrome)

PURPOSE

This paper reviews current knowledge about the pathogenesis, clinical manifestations and treatment of lattice corneal dystrophy, gelsolin type (LCD2, Meretoja's syndrome).

METHODS

Material is derived from literature searches, a case study of a Finnish patient living in Sweden, and interviews in Helsinki with Professor Ahti Tarkkanen and Dr Sari Kiuru-Enari, both of whom have extensive first-hand experience in treating patients with the disease.

RESULTS

The disease is now reported from several countries in Europe, as well as Japan, the USA and Iran. Treatment is symptomatic and is based on eye lubrication combined with rigorous monitoring of intraocular pressure to reduce corneal haze and postpone the need for keratoplasty. When systemic symptoms occur, the ophthalmologist should consult other specialists.

CONCLUSIONS

The disease is probably under-reported and is almost certainly to be found in more countries, including Sweden. Every ophthalmologist should be vigilant and consider this diagnosis when discovering a corneal lattice dystrophy, especially because the disease is an inherited, lifelong chronic condition with systemic symptoms.

Probing mechanisms of axonopathy. Part I: Protein targets of 1,2-diacetylbenzene, the neurotoxic metabolite of aromatic solvent 1,2-diethylbenzene

Motor neuron axonopathy in diseases such as amyotrophic lateral sclerosis can be modeled and probed with neurotoxic chemicals that induce similar patterns of pathology, such as axonal spheroids that represent focal accumulation of anterogradely transported neurofilaments (NFs). The aromatic gamma-diketone-like 1,2-diacetylbenzene (1,2-DAB), but not its 1,3-DAB isomer, reacts with epsilon-amino- or sulfyhydryl groups of (neuro)proteins, forms adducts, and causes NFs to accumulate at proximal sites of elongate motor axons. We exploit the protein-reactive properties of neurotoxic 1,2-DAB versus the nonprotein-reactive properties of non-neurotoxic 1,3-DAB to unveil proteomic changes associated with this type of pathology. We used two-dimensional differential in-gel electrophoresis (2D-DIGE), matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry to analyze the lumbosacral spinal cord proteome of adult Sprague-Dawley rats treated systemically with 20 mg/kg/day 1,2-DAB, equimolar dose of 1,3-DAB, or equivalent volume of vehicle (saline containing 2% acetone), 5 days a week, for 2 weeks. 1,2-DAB significantly altered the expression of protein disulfide isomerase, an enzyme involved in protein folding, and gelsolin, an actin-capping and -severing protein. Modifications of these two proteins have been incriminated in the pathogenesis of nerve fiber degeneration. Protein-reactive and neurotoxic 1,2-DAB appears to be excellent tool to dissect mechanisms of nerve fiber (axon) degeneration.