Clinical and Genetic Evaluation of People with or at Risk of Hereditary ATTR Amyloidosis: An Expert Opinion and Consensus on Best Practice in Ireland and the UK

AL type renal amyloidosis with cardiac involvement: A case report and literature review

RATIONALE

Systemic amyloidosis refers to a spectrum of diseases characterized by extracellular deposition of amyloids, with commonrenal involvement; however, simultaneous involvement of cardiac amyloidosis remains rare. The purpose of this report was to enhance the understanding of the diagnosis and treatment of light chain (AL)-type renal amyloidosis with cardiovascular involvement, reduce misdiagnosis and missed diagnosis, and enable timely and effective treatment for such patients.

PATIENT CONCERNS

A 74-year-old male patient was admitted to our hospital because of recurrent edema for over 1 year and aggravated recurrence with decreased urine for 1 month. Pathological examination of the renal biopsy specimen showed homogeneous nonstructural material deposition in the glomerular mesangial area.

DIAGNOSES

This patient was diagnosed with lightchain (AL)-type renal amyloidosis with cardiac involvement.

INTERVENTIONS

Treatment with daretomumab (DARA) 800mg plus cyclophosphamide 0.4g, bortezomib 1.6mg and dexamethasone 20mg (D-VCD regimen). Interventions, such as intermittent diuresis, anticoagulation, and electrolyte imbalance, were administered.

OUTCOMES

After 2 courses of chemotherapy, edema was relieved, urine protein was reduced, and symptoms improved. Chemotherapy was continued in accordance with the regimen described above.

LESSONS

Due to the rarity and nonspecific symptoms, missed diagnosis and misdiagnosis of AL-type renal amyloidosis remain common. Among patients with a confirmed diagnosis, in addition to considering the pathological changes in the kidney, consideration of the presence of amyloidosis in other organs, such as cardiac involvement, is also necessary.

Hereditary Transthyretin Amyloidosis in Patients Referred to a Genetic Testing Program

BACKGROUND

Diagnosis of hereditary amyloid transthyretin (hATTR) amyloidosis with cardiomyopathy is frequently delayed, in large part because of symptom overlap with other cardiovascular diseases and limited provider knowledge of this disease. The sponsored and provider referred hATTR Compass Genetic Testing Program (Ionis, Carlsbad, CA; Ambry Genetics, Aliso Viejo, CA) provided no-cost genetic testing to adults with a family history or clinical suspicion of hATTR amyloidosis. This study aims to characterize patients with hATTR amyloidosis and increase awareness of genetic testing for hATTR.

METHODS AND RESULTS

Patients were referred to the hATTR genetic testing program, and a cross-sectional post hoc analysis was performed. A pathogenic TTR variant was identified in 1503 (6.6%) of 22 886 patients referred for genetic testing between June 2018 and March 2022. Patients were identified in all US states, 3 US territories, and Canada. Median age at testing was 63 years, and 44% were female. The p.V142I TTR variant was the most common (n=1263, 84.0%). Only 32% of patients with a pathogenic TTR variant reported a known family history; a lower percentage of Black individuals reported a known family history compared with other racial and ethnic groups. Black patients accounted for 23.7% of all patients referred and 81.9% of patients with the p.V142I variant.

CONCLUSIONS

This sponsored genetic testing program identified a large number of patients with a pathogenic TTR variant, notably, in geographic regions not previously reported, and demographic groups that are historically underrepresented in the literature.

Exploring the Utility of Carpal Tunnel Biopsy in Amyloidosis: A Current Perspective

Recent literature has emphasized the role of hand surgeons in screening patients with carpal tunnel syndrome (CTS) for amyloidosis by performing a carpal tunnel synovial biopsy during open carpal tunnel release (CTR). This has led to misconceptions about the diagnostic utility of synovial biopsy and the clinical evaluation of suspected amyloidosis. Controversy over carpal tunnel biopsy is exacerbated by minimally invasive advances in CTR procedures. This current perspective aims to determine the role of carpal tunnel synovial biopsy in amyloidosis and provide an update for hand surgeons regarding the nuances of amyloidosis. We conclude that carpal tunnel synovial biopsy should not be performed without CTS symptoms but only in patients meeting criteria for open CTR such as in those with severe symptoms which have failed nonoperative treatment and minimally invasive procedures are contraindicated. A screening approach for amyloidosis is proposed in patients presenting with CTS symptoms. Despite advances in the understanding, treatment, and diagnosis of amyloidosis, there remains a need for accurate, specific, and sensitive diagnostic tests.

[Proposals for the early diagnosis of late-onset hereditary ATTR amyloidosis in ‍nonendemic areas in Japan]

Late-onset hereditary ATTR (ATTRv) amyloidosis in nonendemic areas takes long periods of time to diagnose in many cases because the clinical symptoms are varied and nonspecific with the family history often unidentifiable. In recent years, disease-modifying therapies have been available for ATTRv amyloidosis, and early diagnosis is increasingly needed. The diagnosis of ATTRv amyloidosis usually requires histological confirmation of the amyloid deposition, although the amyloid detection rate largely depends on the experience, knowledge, and skill of the physician who performs the biopsy. It is important to consider ATTRv amyloidosis as a differential disease in idiopathic polyneuropathy. If ATTRv amyloidosis is strongly suspected, it is acceptable to perform TTR genetic testing prior to histological examination after a thorough differential diagnosis has been made.

Genetic counselling for at-risk family members with hereditary transthyretin amyloidosis: data from a single-centre study

BACKGROUND

Hereditary transthyretin-related amyloidosis is an autosomal dominant disorder. Recently, disease-modifying therapies (DMTs) have been developed. For at-risk individuals, genetic analysis aids in the early administration of medical care; however, few studies have evaluated the current status of genetic counselling and management of presymptomatic carriers of amyloidogenic variants.

METHODS

We retrospectively evaluated the medical records of 202 consecutive participants.

RESULTS

A total of 103 clients who received genetic counselling for predictive testing were at-risk, and 83 underwent predictive testing. Genetic testing results were positive in 33 patients, 11 of whom had confirmed amyloid deposition and were administered DMTs. For presymptomatic V30M (p.V50M) carriers, 32.0 ± 2.4 years (median ± standard error) was the age when amyloid deposition was first identified (95% confidence interval 27.4-36.6). Serum transthyretin (TTR) levels decreased serially with an estimated slope of -1.2 mg/dL/year.

CONCLUSIONS

Our study suggests the clinical utility of management using a combination of predictive testing and monitoring methods. Psychosocial support should be considered with collaboration between geneticists/genetic counsellors and psychologists. For a more optimised protocol for monitoring and designing future interventional trials in presymptomatic carriers, prospective cohort studies are necessary to clarify the natural history, particularly in the early stages of the disease.

Value of multi-modality small fiber assessments in a genotypically diverse cohort of transthyretin-related amyloidosis in the early stages of disease

INTRODUCTION

Transthyretin-related amyloidosis (ATTRv) is a progressive multisystem disorder, predominantly involving the peripheral nerve system (PNS) and heart. Quantification of small fiber damage may help guide treatment decisions, as amyloid deposits frequently affect those fibers early in disease course. Corneal confocal microscopy (CCM) is a promising method to monitor patients with ATTRv, due to similarities between corneal nerves and PNS, as the cornea is innervated by Aδ and C fibers.

METHODS

We compared CCM measures from ATTRv patients to a group of healthy individuals, matched by age and gender. We then investigated the correlations between small fiber tests (SFT): CCM, LDI-Flare and CDT, COMPASS-31 and disability scales (RODS and ONLS) in patients.

RESULTS

Of 20 patients (6 with V30M), mean age 50.3±15.3Y, 7 female (35%), six (30%) had polyneuropathy and 10 (50%) carpal tunnel syndrome. CDT was abnormal in 9 and LDI-flare in 6 patients. CCM was abnormal in 19 tested patients and significantly reduced when compared to controls (CNFL: 6.31±0.31 vs. 15.21±1.02mm/mm2, p<0.001). Mean COMPASS-31-scores were 22.27±22.84; RODS and ONLS were 38.15±12.33 and 2.05±2.3, with no significant differences between sub-group scores. Disease duration was significantly correlated with ONLS (0.43, p=0.05) and RODS (0.46, p=0.03). There were no significant correlations between measures of disability and SFT.

CONCLUSIONS

In a diverse cohort of ATTRv patients, CCM was the most frequent abnormal measurement. CCM can be a useful test to triage patients in the early disease stages and with few or equivocal symptoms.

Early diagnosis in ATTRv amyloidosis, how early is enough? How early is possible?

Hereditary transthyretin amyloidosis (ATTRv amyloidosis) is a rare, progressive, and debilitating genetic disorder characterized by the deposition of abnormal transthyretin (TTR) protein aggregates in various tissues, leading to organ dysfunction. Early diagnosis of ATTRv amyloidosis is critical for starting timely interventions and improving patient outcomes. This review explores the concepts of "how early is enough" and "how early is possible" in the context of diagnosing ATTRv amyloidosis, highlighting the challenges and opportunities for early recognition.

Clinical suspicion, diagnosis and management of cardiac amyloidosis: update document and executive summary

In recent years, the interest in cardiac amyloidosis has grown exponentially. However, there is a need to improve our understanding of amyloidosis in order to optimise early detection systems. Therefore, it is crucial to incorporate solutions to improve the suspicion, diagnosis and follow-up of cardiac amyloidosis. In this sense, we designed a tool following the different phases to reach the diagnosis of cardiac amyloidosis, as well as an optimal follow-up: a) clinical suspicion, where the importance of the "red flags" to suspect it and activate the diagnostic process is highlighted; 2) diagnosis, where the diagnostic algorithm is mainly outlined; and 3) follow-up of confirmed patients. This is a practical resource that will be of great use to all professionals caring for patients with suspected or confirmed cardiac amyloidosis, to improve its early detection, as well as to optimise its accurate diagnosis and optimal follow-up.

2024 Australia-New Zealand Expert Consensus Statement on Cardiac Amyloidosis

Over the past 5 years, early diagnosis of and new treatments for cardiac amyloidosis (CA) have emerged that hold promise for early intervention. These include non-invasive diagnostic tests and disease modifying therapies. Recently, CA has been one of the first types of cardiomyopathy to be treated with gene editing techniques. Although these therapies are not yet widely available to patients in Australia and New Zealand, this may change in the near future. Given the rapid pace with which this field is evolving, it is important to view these advances within the Australian and New Zealand context. This Consensus Statement aims to update the Australian and New Zealand general physician and cardiologist with regards to the diagnosis, investigations, and management of CA.

Extending the reach of expert amyloidosis care: A feasibility study exploring the staged implementation of a UK amyloidosis network

There has been an exponential increase in the diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CA). In response, the Midlands Amyloidosis Service was launched with the aim of providing patients with a timely diagnosis, remote expertise from the National Amyloidosis Centre and access to emerging transthyretin (TTR)-directed therapies. This was a descriptive study of a pilot hub-and-spoke model of delivering specialist amyloidosis care. Patients with suspected amyloidosis were referred from the wider Midlands region, and seen in a consultant-led multidisciplinary clinic. The diagnosis of ATTR-CA was established according to either the validated non-biopsy criteria or histological confirmation of ATTR deposits with imaging evidence of amyloid. Study endpoints were the volume of service provision and the time to diagnosis from the receipt of referral. Patients (n=173, age 75±2 years; male 72 %) were referred between 2019 and 2021. Eighty patients (46 %) were found to have cardiac amyloidosis, of whom 68 (85 %) had ATTR-CA. The median time from referral to diagnosis was 43 days. By removing the need for patients to travel to London, an average of 187 patient-miles was saved. Fifteen (9 %) patients with wild-type ATTR-CA received tafamidis under the Early Access to Medicine scheme; 10 (6 %) were enrolled into phase 3 clinical trials of RNA interference or antisense oligonucleotide therapies. Our results suggest that implementing a UK amyloidosis network appears feasible and would enhance equity of access to specialised amyloidosis healthcare for the increasing numbers of older patients found to have ATTR-CA.

Hereditary transthyretin amyloid neuropathies: advances in pathophysiology, biomarkers, and treatment

Hereditary transthyretin (TTR) amyloid polyneuropathy is an autosomal dominant life-threatening disorder. TTR is produced mainly by the liver but also by the choroid plexus and retinal pigment epithelium. Detailed clinical characterisation, identification of clinical red flags for misdiagnosis, and use of biomarkers enable early diagnosis and treatment. In addition to liver transplantation and TTR stabilisers, three other disease-modifying therapies have regulatory approval: one antisense oligonucleotide (inotersen) and two small interfering RNAs (siRNAs; patisiran and vutrisiran). The siRNAs have been shown to stop progression of neuropathy and improve patients' quality of life. As none of the disease-modifying therapies can cross the blood-brain barrier, TTR deposition in the CNS, which can cause stroke and cognitive impairment, remains an important unaddressed issue. CRISPR-Cas9-based one-time TTR editing therapy is being investigated in a phase 1 clinical study. Identification of the earliest stages of pathogenesis in TTR variant carriers is a major challenge that needs addressing for optimal management.

Optimal practices for the management of hereditary transthyretin amyloidosis: real-world experience from Japan, Brazil, and Portugal

Hereditary transthyretin (ATTRv) amyloidosis is a rare and autosomal dominant disorder associated with mutations in the transthyretin gene. Patients present with diverse symptoms related to sensory, motor, and autonomic neuropathy, as well as gastrointestinal, ocular, cardiac, renal and orthopedic symptoms, resulting from the deposition of transthyretin amyloid fibrils in multiple organs. The progressive nature of ATTRv amyloidosis necessitates pre- and post-onset monitoring of the disease. This review article is primarily based on a collation of discussions from a medical advisory board meeting in August 2021. In this article, we summarize the best practices in amyloidosis centers in three major endemic countries for ATTRv amyloidosis (Japan, Brazil, and Portugal), where most patients carry the Val30Met mutation in the transthyretin gene and the patients' genetic background was proven to be the same. The discussions highlighted the similarities and differences in the management of asymptomatic gene mutation carriers among the three countries in terms of the use of noninvasive tests and tissue biopsies and timing of starting the investigations. In addition, this article discusses a set of practical tests and examinations for monitoring disease progression applicable to neurologists working in diverse medical settings and generalizable in non-endemic countries and areas. This set of assessments consists of periodic (every 6 to 12 months) evaluations of patients' nutritional status and autonomic, renal, cardiac, ophthalmologic, and neurological functions. Physical examinations and patient-reported outcome assessments should be also scheduled every 6 to 12 months. Programs for monitoring gene mutation carriers and robust referral networks can aid in appropriate patient management in pre- to post-onset stages. For pre- and post-symptom onset testing for ATTRv amyloidosis, various noninvasive techniques are available; however, their applicability differs depending on the medical setting in each country and region, and the optimal option should be selected in view of the clinical settings, medical environment, and available healthcare resources in each region.

A multicentric study of the disease risks and first manifestations in hereditary transthyretin amyloidosis (ATTRv): insights for an earlier diagnosis

BACKGROUND

In hereditary transthyretin amyloidosis (ATTRv), early manifestation and age at onset (AO) may vary strikingly. We assessed the disease'risk (penetrance), AO and initial features in ATTRv families to gain insights on the early disease presentation.

METHODS

Genealogical information, AO and first disease manifestations were collected in ATTRv families, from Sweden, Italy (Sicily), Spain (Mallorca), France, Turkey, Brazil. Penetrance was computed using a non-parametric survival method.

RESULTS

We analysed 258 TTRV30M kindreds and 84 carrying six other variants (TTRT49A, F64L, S77Y, S77F, E89Q, I107V). In ATTRV30M families, the earliest disease risk was found at age 20 years in the Portuguese and Mallorcan families and at age 30-35 years, in the French and Swedish groups. The risks were higher in men and in carriers of maternal descent. In families carrying TTR-nonV30M variants, the earliest disease risk ranged from 30 y-o in TTRT49A to 55 y-o in TTRI107V families. Peripheral neuropathy symptoms were the most frequent initial manifestations. Among patients carrying TTRnonV30M variants, about 25% had an initial cardiac phenotype, one third a mixed phenotype.

CONCLUSION

Our work provided solid data on the risks and early features of ATTRv in a spectrum of families to enhance an early diagnosis and treatment.

British Society of Echocardiography guideline for the transthoracic echocardiographic assessment of cardiac amyloidosis

These guidelines form an update of the BSE guideline protocol for the assessment of restrictive cardiomyopathy (Knight et al. in Echo Res Prac, 2013). Since the original recommendations were conceived in 2013, there has been an exponential rise in the diagnosis of cardiac amyloidosis fuelled by increased clinician awareness, improvements in cardiovascular imaging as well as the availability of new and effective disease modifying therapies. The initial diagnosis of cardiac amyloidosis can be challenging and is often not clear-cut on the basis of echocardiography, which for most patients presenting with heart failure symptoms remains the first-line imaging test. The role of a specialist echocardiographer will be to raise the suspicion of cardiac amyloidosis when appropriate, but the formal diagnosis of amyloid sub-type invariably requires further downstream testing. This document seeks to provide a focused review of the literature on echocardiography in cardiac amyloidosis highlighting its important role in the diagnosis, prognosis and screening of at risk individuals, before concluding with a suggested minimum data set, for use as an aide memoire when reporting.

A review of transthyretin cardiac amyloidosis

Transthyretin cardiac amyloidosis is a progressive disease known to cause heart failure, conduction anomalies, and arrythmias. Due to poor outcomes and mortality from severe cardiomyopathy, prevalence and incident rates are often underreported. As global longevity is increasing and rates of amyloidosis are also increasing, there is a need to improve diagnostic and therapeutic interventions. Previously, symptom management and transplantation were the mainstay of treatment for heart failure symptoms, but studies using RNAi and siRNA technologies have shifted the paradigm of therapeutic strategy in amyloid cardiomyopathy management. Additionally, early detection and clinical monitoring with numerous imaging and non-imaging techniques are being increasingly investigated. Here, we review the epidemiology, pathophysiology, diagnosis, and management of transthyretin amyloid cardiomyopathy.

Prevalence, characteristics and outcomes of older patients with hereditary versus wild-type transthyretin amyloid cardiomyopathy

AIMS

Transthyretin amyloid cardiomyopathy (ATTR-CM) is often assumed to be associated with wild-type TTR genotype (ATTRwt) in elderly patients (aged ≥70), some of whom are not offered genetic testing. We sought to estimate the prevalence, clinical characteristics and prognostic implications of transthyretin (TTR) variants among elderly patients diagnosed with ATTR-CM.

METHODS AND RESULTS

Data from consecutive patients over 70 years of age diagnosed with ATTR-CM at the UK National Amyloidosis Centre between January 2010 and August 2022 were retrospectively evaluated. All patients underwent clinical evaluation, biochemical tests, echocardiography and TTR genotyping. The study outcome was all-cause mortality. The study population consisted of 2029 patients with ATTR-CM (median age 79 years at diagnosis, 13.5% females, 80.4% Caucasian). Variant ATTR-CM (ATTRv-CM) was diagnosed in 20.7% (n = 421) of the study population of whom 327 (77.7%) carried V122I, 47 (11.2%) T60A, 16 (3.8%) V30M and 31 (7.3%) other pathogenic TTR variants. During a median (range) follow-up of 29 (12-48) months, ATTRv-CM was associated with increased all-cause mortality compared to ATTRwt-CM, with the poorest survival observed in V122I-associated ATTRv-CM (p < 0.001). Univariable and multivariable logistic regression analyses in those with ATTR-CM showed younger age at diagnosis (odds ratio [OR] 0.85 per year, p < 0.001), female sex (OR 2.73, p < 0.001), Afro-Caribbean ethnicity (OR 65.5, p < 0.001), atrial fibrillation (OR 0.65, p = 0.015), ischaemic heart disease (OR 0.54, p = 0.007), peripheral polyneuropathy (OR 5.70, p < 0.001) and orthostatic hypotension (OR 6.29, p < 0.001) to be independently associated with ATTRv-CM.

CONCLUSION

Up to 20.7% of elderly patients with ATTR-CM have a pathogenic TTR variant. These findings support routine sequencing of the TTR gene in all patients with ATTR-CM regardless of age.

Multimodality imaging in cardiac amyloidosis: State-of-the-art review

Amyloidosis is a systemic disease, characterized by deposition of amyloid fibrils in various organs, including the heart. For the diagnosis of cardiac amyloidosis (CA) it is required a high level of clinical suspicion and in the presence of clinical, laboratorial, and electrocardiographic red flags, a comprehensive multimodality imaging evaluation is warranted, including echocardiography, magnetic resonance, scintigraphy, and computed tomography, that will confirm diagnosis and define the CA subtype, which is of the utmost importance to plan a treatment strategy. We will review the use of multimodality imaging in the evaluation of CA, including the latest applications, and a practical flow-chart will sum-up this evidence.