Detailed clinical, physiological and pathological phenotyping can impact access to disease-modifying treatments in ATTR carriers

BACKGROUND

Hereditary transthyretin amyloidosis is a life-threatening autosomal dominant systemic disease due to pathogenic TTR variants (ATTRv), mostly affecting the peripheral nerves and heart. The disease is characterised by a combination of symptoms, organ involvement and histological amyloid deposition. The available disease-modifying ATTRv treatments (DMTs) are more effective if initiated early. Pathological nerve conduction studies (NCS) results are the cornerstone of large-fibre polyneuropathy diagnosis, but this anomaly occurs late in the disease. We investigated the utility of a multimodal neurological and cardiac evaluation for detecting early disease onset in ATTRv carriers.

METHODS

We retrospectively analysed a cohort of ATTRv carriers with normal NCS results regardless of symptoms. Multimodal denervation and infiltration evaluations included a clinical questionnaire (Lauria and New York Heart Association (NYHA)) and examination, intra-epidermal nerve fibre density assessment, autonomic assessment based on heart rate variability, Sudoscan, meta-iodo-benzyl-guanidine scintigraphy, cardiac biomarkers, echocardiography, MRI and searches for amyloidosis on skin biopsy and bone scintigraphy.

RESULTS

We included 130 ATTRv carriers (40.8% men, age: 43.6±13.5 years), with 18 amyloidogenic TTR gene mutations, the majority of which was the late-onset Val30Met variant (42.3%). Amyloidosis was detected in 16.9% of mutation carriers, including 9 (6.9%) with overt disease (Lauria>2 or NYHA>1) and 13 asymptomatic carriers (10%) with organ involvement (small-fibre neuropathy or cardiomyopathy). Most of these patients received DMT. Abnormal test results of unknown significance were obtained for 105 carriers (80.8%). Investigations were normal in only three carriers (2.3%).

CONCLUSIONS

Multimodal neurological and cardiac investigation of TTRv carriers is crucial for the early detection of ATTRv amyloidosis and initiation of DMT.

Skin amyloid deposits and nerve fiber loss as markers of neuropathy onset and progression in hereditary transthyretin amyloidosis

OBJECTIVE

To assess skin biopsy as marker of disease onset and severity in hereditary transthyretin amyloidosis with polyneuropathy (ATTRv-PN), a treatable disease.

METHODS

In this single center retrospective study, skin Congo red staining and intraepidermal nerve fiber density (IENFD) were evaluated in symptomatic ATTRv-PN patients and asymptomatic TTR gene mutation carriers between 2012 and 2019. Non-ATTRv subjects with small fiber neuropathy suspicion who underwent skin biopsy in the same timespan were used as controls.

RESULTS

One-hundred-eighty-three symptomatic ATTRv-PN, 36 asymptomatic carriers, and 537 non-ATTRv patients were included. Skin biopsy demonstrated amyloid depositions in 80% of the 183 symptomatic cases. Skin amyloid deposits were found in 75% of early-stage ATTRv-PN patients, and in 14% of asymptomatic carriers. All 183 symptomatic and 34/36 asymptomatic patients displayed decreased ankle IENFD with a proximal-distal gradient distribution, and reduced IEFND correlated with disease severity and duration.

CONCLUSIONS

Our study demonstrates skin amyloid deposits are a marker of ATTRv-PN disease onset, and decreased IENFD a marker of disease progression. These results are of major importance for the early identification of ATTRv-PN patients in need of disease-modifying treatments.

E-TAN, a technology-enhanced platform with tangible objects for the assessment of visual neglect: A multiple single-case study

Visual neglect is a frequent and disabling consequence of right brain damage. Traditional paper-and pencil tests of neglect have limited sensitivity and ecological validity. The Baking Tray Task (BTT), instead, approaches real-life situations, because it requires participants to place 16 physical objects on a board. The number of objects placed on the left and right portions of the board provides a clinical index of visual neglect. Here we present E-TAN, a technology-enhanced platform for BTT (E-BTT). E-BTT automatically determines the object locations on the board, and also records the sequence and timing of their placement. We used E-BTT to test 9 patients with right hemisphere damage and compared their performance with that obtained by 115 healthy participants. To this end, we developed a new method of analysis of participants' performance, based on the use of the convex hull described by the objects on the board. This measure provides an estimate of the portion of space processed by each participant and can effectively discriminate neglect patients from patients without neglect. E-TAN allows clinicians to assess visuospatial performance by using a convenient, fast, and relatively automatized procedure, that patients can even perform at home to follow-up the effects of rehabilitation.

Early detection of skin and cardiac amyloid deposits among asymptomatic carriers of hereditary pathogenic transthyretin mutation with normal electroneuromyography

Introduction

During the last decade, disease modifying therapies have been proposed for hereditary amyloidogenic transthyretin (ATTRv) amyloidosis. It is essential to screen for disease onset among asymptomatic mutation carriers in order to trigger effective therapy as early as possible. We describe clinical and paraclinical data from ATTRv asymptomatic carriers, as a baseline assessment to detect disease onset and progression.

Methods

We retrospectively collected data of asymptomatic ATTRv carriers with normal electroneuromyography (ENMG), between March 1st 2015 and January 31st 2019, including: demographics, symptoms, physical exam, ENMG (initial and follow-up obtained in 73 patients, 56.2%), neurovegetative tests, skin biopsy (amyloid deposition, denervation), and cardiac evaluation (multimodal imaging, cardiac denervation and arrhythmias).

Results

We included 130 patients, aged 43.6 years (± 13.5), selected in family of a proband with an age of onset of 52.7 years (±15.7), 40.8% male, carrying 20 different variants of the TTR gene, including 63.8% Val30Met. Amyloid deposits on skin biopsy and/or cardiac fixation on bone scintigraphy, characteristic of amyloid infiltration, were found in 22/130 patients (16%). Skin biopsy was positive in 11 patients, and cardiac fixation on bone scintigraphy was positive in 15 patients. Amyloid infiltration was statistically associated with age (p=0.024), age difference from index case (p<0.001), electrophysiological carpal tunnel syndrome (p=0.022), interventricular septum thickness >12 mm (p<0.001), contrast enhancement in cardiac MRI (p=0.002), cardiac denervation using MIBG scintigraphy C/M ratio <1.85 (p=0.044). Multivariate analysis showed that age difference with index case and interventricular septum thickness were predictors for amyloid infiltration (OR=1.11, IC [1,04–1,19] and OR=1,76, IC [1,19–2,60]). Subgroup analysis showed electroneuromyography alteration during follow up in 11 patients (delay 26.9 months, range 10–49) with statistic association with amyloid deposits (55.6 versus 7.1% when ENMG was unchanged, p<0.001) and interventricular septum thickness (p<0.010).

Conclusion

Clinical and paraclinical assessment of asymptomatic carriers of ATTRv mutations shows that skin or cardiac amyloid infiltration may precede ENMG abnormalities in 16% of patients. This may trigger specific therapies in borderline cases. Age close to age of onset among index case and septum interventricular thickness appear as risk factors for developing electroneuromyogram alteration.

Funding Acknowledgement

Type of funding source: None

Inherited Thrombotic Thrombocytopenic Purpura Revealed by Recurrent Strokes in a Male Adult: Case Report and Literature Review

Thrombotic thrombocytopenic purpura (TTP) is a thrombotic microangiopathy related to a severe deficiency of ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13). In this article, we describe the first case of a young male adult suffering from a hereditary TTP revealed by recurrent strokes, relapsing despite antiplatelet and anticoagulant therapy. Because of the persistent moderate thrombocytopenia, plasmatic ADAMTS13 activity was investigated and was found lower than 5% in the absence of anti-ADAMTS13 IgG. Direct sequencing of ADAMTS13 gene led to the diagnosis of Upschaw-Schulman syndrome (USS). Inherited TTP or USS is a rare autosomal recessive inherited disease leading to a severe deficiency of ADAMTS13 mostly beginning in childhood or in young female adult during pregnancy. Our patient was treated with fresh frozen plasma every 2 weeks. One year after diagnosis, he was free of neurological symptoms. Around 12 cases of inherited TTP diagnosed in adults (outside pregnancy) are described in literature. Only 4 of them exhibited a stroke. This case is the first late onset genetic TTP revealed by recurrent strokes, moderate thrombocytopenia without anemia.

Effect of angiotensin-converting enzyme inhibitor therapy in mitral regurgitation with normal left ventricular function

Mitral regurgitation (MR) is a common, frequently asymptomatic valvulopathy that can ultimately lead to left ventricular failure. With the objective of forestalling MR progression, a prospective, placebo controlled, double-blind study was conducted. It measured the effectiveness of lisinopril, an angiotensin-converting enzyme inhibitor, in reducing the echocardiographic signs of MR severity over a one-year period. Severe coronary disease was excluded by stress echocardiography. Treatment effectiveness was estimated to be proportional to the reduction in MR fraction and cardiac chamber dimensions, compared with baseline, according to intention-to-treat analysis. A final patient population of 23 asymptomatic adults aged 53.3 +/- 2.4 years (mean +/- SEM), with moderate, organic MR and normal left ventricular function was selected from the echocardiographic database. All baseline patient characteristics were comparable in the two treatment groups, including the MR fraction (55 +/- 3%). Twelve patients received lisinopril (18 +/- 1 mg) and 11 received placebo. After one year of treatment, a statistically significant difference in the MR fraction was observed between the two groups. For the lisinopril group the MR fraction dropped by 6.4 +/- 3.5% and for the placebo group it increased by 3.7 +/- 3.2% versus baseline (P < 0.05). No differences in left atrial or ventricular dimensions were observed. The study drug was stopped in four patients after one patient presented with rapid atrial fibrillation and angina while three patients were intolerant to lisinopril. Only one patient receiving placebo was taken off therapy. In conclusion, treatment with lisinopril indicates some reduction in the severity of chronic moderate MR in asymptomatic patients with normal left ventricular function. This approach appears to be safe, but side effects are not uncommon, warranting regular follow-up.