Familial primary amyloidosis with severe amyloid heart disease

Degradation versus fibrillogenesis, two alternative pathways modulated by seeds and glycosaminoglycans

The mechanism that converts native human transthyretin into amyloid fibrils in vivo is still a debated and controversial issue. Commonly, non-physiological conditions of pH, temperature, or organic solvents are used in in vitro models of fibrillogenesis of globular proteins. Transthyretin amyloid formation can be achieved under physiological conditions through a mechano-enzymatic mechanism involving specific serine proteases such as trypsin or plasmin. Here, we investigate S52P and L111M transthyretin variants, both causing a severe form of systemic amyloidosis mostly targeting the heart at a relatively young age with heterogeneous phenotype among patients. Our studies on thermodynamics show that both proteins are significantly less stable than other amyloidogenic variants. However, despite a similar thermodynamic stability, L111M variant seems to have enhanced susceptibility to cleavage and a lower tendency to form fibrils than S52P in the presence of specific proteases and biomechanical forces. Heparin strongly enhances the fibrillogenic capacity of L111M transthyretin, but has no effect on the S52P variant. Fibrillar seeds similarly affect the fibrillogenesis of both proteins, with a stronger effect on the L111M variant. According to our model of mechano-enzymatic fibrillogenesis, both full-length and truncated monomers, released after the first cleavage, can enter into fibrillogenesis or degradation pathways. Our findings show that the kinetics of the two processes can be affected by several factors, such as intrinsic amyloidogenicity due to the specific mutations, environmental factors including heparin and fibrillar seeds that significantly accelerate the fibrillogenic pathway.

Transthyretin Gene Variants and Associated Phenotypes in Danish Patients with Amyloid Cardiomyopathy

Genotyping divides transthyretin cardiac amyloidosis (ATTR-CA) in hereditary (ATTRv) and wild type (ATTRwt) forms. This study investigated the prevalence and clinical presentation of ATTRv in a contemporary cohort of consecutive ATTR-CA patients diagnosed at a tertiary Danish amyloidosis center. Age at diagnosis, clinical- and echocardiographic data, and transthyretin (TTR) genotype were recorded. Relatives of ATTRv patients underwent clinical phenotyping and predictive gene testing. Genetic testing in 102 patients identified four TTR variant carriers: p.Pro63Ser, p.Ala65Ser (n = 2) and p.Val142Ile. The mean age of ATTRv index patients was significantly lower compared to ATTRwt patients: 70.2 ± 1.2 versus 80.0 ± 6.2, p-value: 0.005. Evaluation of ATTRv families identified seven TTR variant carriers with a median age of 65 years (range 48–76) and three were diagnosed with ATTR-CA by DPD-scintigraphy. Family members with ATTR-CA were all asymptomatic and had normal levels of cardiac biomarkers. In conclusion, the prevalence of ATTRv in a contemporary Danish ATTR-CA cohort is 4%. ATTRv index patients were significantly younger age at diagnosis than ATTRwt patients. Non-p.Leu131Met TTR variants have reduced penetrance at the age of 65 years in which approximately half of variant carriers have asymptomatic ATTR-CA with normal LV systolic function and cardiac biomarker analyses.

Heart complications in familial transthyretin amyloidosis: impact of age and gender

Heart arrhythmia is common in Swedish patients with familial amyloidotic polyneuropathy (FAP), as well as cardiomyopathy. We investigated the relationship between Holter ECG and echocardiographic findings in 108 FAP patients, with particular focus on age and gender differences. Female patients were younger than male patients at symptom onset (p < 0.01). Only 4 of 39 patients with septal hypertrophy were females. Regression analysis showed that age of onset, gender and duration of disease were significantly related with intraventricular septum (IVS) thickness. Sixty-five patients (25 females) presented with abnormal 24-h ECG recordings. IVS thickness was not significantly related to conduction disturbances or the presence of ventricular arrhythmia (VA). However, IVS thickness and atrial dimension were both related to increased rate of supraventricular arrhythmia (SVA). Male gender was clearly associated with more pronounced septal thickness of the heart. Conduction disturbances were not related to IVS thickness, indicating that the distribution and extent of infiltration of the heart by amyloid are heterogeneous and related to gender and age of onset. These findings highlight the necessity of 24-h ECGs to detect conduction disturbances, due to their occurrence in the absence of echocardiographic evidence of amyloid deposition in the myocardium.

Atrioventricular and intraventricular conduction in familial amyloidosis with polyneuropathy

Atrioventricular and/or intraventricular conduction disturbances were found in 48 (67%) out of 71 patients with familial amyloidosis with polyneuropathy. Low voltage, often described in various forms of heart amyloidosis, was seen in one patient only. Myocardial infarction patterns, also often reported in heart amyloidosis, were not present in our patients. The prevalence of conduction disturbances increased with the duration of the disease. In 28 out of 47 patients from whom more than one ECG recording was available, a progression of conduction disturbances could be seen. Ten patients developed high-degree conduction disturbances and required permanent pacemaker treatment.

Hemodynamic and angiocardiographic observations in familial amyloidosis with polyneuropahy

Eleven patients with familial amyloidosis with polyneuropathy were studied by heart catheterization; eight of them also by right and left ventriculography and selective coronary angiography. Signs of congestive heart failure, often reported as typical of cardiac amyloidosis, were found in only one patient. The systolic function was relatively unimpaired, but in several patients hemodynamic data suggested restrictive cardiomyopathy. Six patients showed signs of right or left ventricular outflow tract obstruction. Thus, no uniform hemodynamic pattern could be identified, but the changes found indicate impaired diastolic function.

Liver Transplantation for Familial Amyloid Polyneuropathy Non-VAL30MET Variants: Are Cardiac Complications Influenced by Prophylactic Pacing and Immunosuppressive Weaning?

BACKGROUND

Cardiac complications represent a cause of morbidity and mortality after liver transplantation among patients with familial amyloid polyneuropathy (FAP), especially for the non-VAL30MET variant types.

METHODS

We retrospectively evaluated 11 recipients from a nonendemic area including 90.9% affected by FAP variants. Preoperative cardiovascular symptoms were present in 81% of patients. An intraoperative pacemaker was placed prophylactically in 90.9% of all recipients. Since tacrolimus has been reported in the international literature to display cardiac toxicity, we evaluated the influence of intraoperative prophylactic pacing and rapid postoperative weaning from tacrolimus, mainly allowed by thymoglobulin on the occurrence of posttransplantation cardiac complications.

RESULTS

One patient received a combined heart-liver transplant, another, living donor liver transplantation. We did not observe any significant intraoperative cardiac complications. Postoperatively, the pacemaker was removed from all patients but 1. Five patients received tacrolimus and steroids; a subsequent, second group of 6 patients (54.5%) was treated with thymoglobulin followed by tacrolimus. At discharge the mean tacrolimus level was 10.6 ng/mL, whereas after 1 month it was 7.5 ng/mL. We observed a case of acute cellular rejection before discharge, which was successfully treated with intravenous steroids and OKT3. After a mean follow-up of 17.4 months (range, 1-31), 2 patients had died (18.1%): 1 due to sepsis and another, to MI. Two recipients experienced cardiac complications (18.1%), namely, the patient who died due to an myocardial infarction and a second one with a tachyarrhythmia, which was treated successfully with beta-blockers and amiodarone.

CONCLUSION

Prophylactic pacing and rapid weaning from immunosuppression are still associated with a significant rate of postoperative cardiac complications.

Amyloid in the cardiovascular system: a review

The cardiovascular system is a common target of amyloidosis. This review presents the current clinical and diagnostic approach to amyloidosis, with the emphasis on cardiovascular involvement. It summarises recent nomenclature, classification, and pathogenesis of amyloidosis. In addition, non-invasive possibilities are discussed, together with endomyocardial biopsies in the diagnosis of cardiac amyloidosis. Finally, recent advances in treatment and prognostic implications are presented.

Differing haemodynamic and catecholamine responses to exercise in three groups with peripheralautonomic dysfunction: insulin-dependent diabetes mellitus, familial amyloid polyneuropathy and pure autonomic failure

The haemodynamic and catecholamine responses to supine exercise, and the effect on standing blood pressure (BP), were studied in three groups with peripheral autonomic dysfunction; insulin-dependent diabetes mellitus (IDDM), familial amyloid polyneuropathy (FAP) and pure autonomic failure (PAF). Healthy normal subjects were studied as controls. With exercise, BP increased in controls, was unchanged in IDDM and FAP, and fell in PAF. Heart rate (HR) increased more in controls than IDDM, FAP or PAF. Cardiac index (CI) increased less in IDDM than controls, FAP or PAF. Systemic vascular resistance (SVR) fell similarly in controls and IDDM, with a greater fall in FAP and PAF. Plasma noradrenaline increased in controls and IDDM only; plasma adrenaline did not change and plasma dopamine was undetectable in all groups. On standing, BP was unchanged in controls; BP fell pre- and post-exercise in IDDM, FAP and PAF, with a significantly greater fall post-exercise in FAP and PAF. In conclusion, the haemodynamic responses to supine exercise and to standing after exercise differed in the three groups with peripheral autonomic dysfunction. These differences, and also the similarities, between different forms of peripheral autonomic dysfunction, may be of relevance to the clinical assessment and therapy of these patients.

Three siblings of familial amyloid cardiomyopathy with isoleucine-50 transthyretin mutation

We herein describe three siblings with familial amyloid cardiomyopathy in a Japanese family, who demonstrated an Ile-50 mutation in the transthyretin gene. In their clinical course, the symptoms started at from 50 to 55 years of age, and two cases died within 5 years. However, one case is still alive seven years after onset probably due to either the implantation of a pacemaker for a complete atrio-ventricular block or the administration of dimethylsulphoxide. Based on our findings, some differences were observed not only in the mutation of the transthyretin gene but also in the clinical course between our cases and the previously reported cases.

Purification and characterization of amyloid-related transthyretin associated with familial amyloidotic cardiomyopathy

Analysis of amyloid fibril material associated with familial amyloidotic cardiomyopathy revealed that it contains a mixture of transthyretin-related polypeptides. The major protein band in SDS/polyacrylamide gel corresponding to a molecular mass of 14.5 kDa, consists of transthyretin fragments starting at positions 46, 49 and 59, the latter not previously identified, and one blocked fragment derived from the N-terminal part of transthyretin. In reverse-phase HPLC, the major fragment recovered was that starting at Thr49, indicating a trypsin-like cleavage (Lys at position 48). Two minor bands, corresponding to 17 kDa and 35 kDa, contained proteins with blocked N-termini, and migrated as monomeric and dimeric transthyretin, respectively. A 13-kDa protein band was found to contain transthyretin with a ragged N-terminus, mainly starting at positions 2 and 5. Three more bands, corresponding to 10, 25 and 29 kDa, consist of transthyretin molecules with blocked N-termini and most likely of aggregates of truncated molecules. A point mutation of amyloid transthyretin was identified at position 111 (Met instead of Leu in normal serum transthyretin) which confirms the mutation found for Danish siblings with familial amyloidotic cardiomyopathy. However, the presence of a non-variant amyloid transthyretin was also observed, indicating that the Danish kindred is heterozygous with respect to this point mutation. Isoelectric focusing of the amyloid fibril material resolved multiple protein bands ranging over pH 4.5-6.5, confirming heterogeneities. Methanol extraction of the cardiac amyloid fibril material prior to the purification steps reveals a methanol-soluble substance amounting to about 10% (by mass dry material) of the amyloid fibril material. A yellow substance in this fraction shows absorbance maxima (270, 280 and 430 nm) similar to those observed for transthyretin in normal serum. Gas chromatography/mass spectrometry of the methanol extract revealed the presence of saturated fatty acids (C14:0, C16:0 and C18:0 in the corresponding ratio 2:8:5) and polyunsaturated fatty acids (C16:1, C18:1, C18:2 and C20:4 in the corresponding ratio of 1:2:1:1) as further constituents of the amyloid fibril material.

Autonomic nervous system and cardiac involvement in familial amyloidosis, Finnish type (FAF)

Familial amyloidosis, Finnish type (FAF), is a gelsolin-related inherited systemic amyloidosis. We report autonomic nervous system and cardiac findings in a study of 30 FAF patients (18 females, 12 males aged 27-74 years; mean 53.9 years). Cardiovascular reflex tests showed a significant decrease in heart rate variation in FAF patients compared with healthy controls. Orthostatic hypotension was found in 9 of 28 FAF patients, but only in 3 of 69 controls. Signs of amyloid cardiopathy were rare at clinical examination and in radio-, echocardio- and electrocardiographic examinations. Histological and immunohistochemical studies revealed amyloid deposition and immunoreactivity against the gelsolin-related FAF amyloid subunit in autonomic nervous system structures and in cardiac tissue in 3 autopsied FAF patients. The results show that minor autonomic nervous system dysfunction can be found in FAF, while clinically significant amyloid cardiopathy or autonomic neuropathy is not characteristic of this type of amyloidosis.

Amyloidosis

Amyloidosis is a heterogenous group of diseases characterized by deposition of a fibrillar, proteinaceous material, amyloid, in various tissues and organs. Increasing knowledge about the different proteins that constitute the amyloid fibrils has made it possible to classify amyloidosis by the fibril protein, which appears more rational than the traditional classification by its clinical expression. A serum protein is the precursor of the amyloid fibril protein in the various systemic forms of amyloidosis. Although the chemical composition of amyloid is presently well known, the pathogenetic processes that convert such proteins into a fibrillar form and lay them down in the tissues are far from clarified. This review describes the amyloid deposits, some putative pathogenetic mechanisms, and the clinical, therapeutic, and prognostic aspects of the most important forms of amyloid disease.

A Danish kindred with familial amyloid cardiomyopathy revisited: identification of a mutant transthyretin-methionine111 variant in serum from patients and carriers

PURPOSE

In familial amyloid cardiomyopathy of Danish origin, the amyloid microfibrils contain a mutant transthyretin (TTR) with a methionine-for-leucine substitution at the molecular position 111. We studied the possible occurrence of this variant TTR-Met111 in serum from afflicted as well as nonafflicted family members and their offspring, in order to define its possible role as predictor of the disease and to describe its mode of inheritance.

PATIENTS AND METHODS

Stored, frozen serum samples obtained from 1959 through 1960 from 36 of 40 living members of the kindred were analyzed. The method employed to detect the abnormal TTR was based on the electrophoretic separation of fragments produced by cyanogen bromide cleavage at the two methionine sites.

RESULTS

All sera from family members with amyloid cardiomyopathy contained the variant transthyretin TTR-Met111 as did sera from half of their offspring. In contrast, nonafflicted family members and their offspring were seronegative for TTR-Met111. Three cousins from the second generation died between 1980 and 1986 of amyloid cardiomyopathy. The presence of variant TTR-Met111 preceded their deaths by 20 to 26 years.

CONCLUSIONS

The occurrence in serum of the mutant transthyretin TTR-Met111 is linked to the occurrence of amyloid cardiomyopathy in patients and their offspring, while unafflicted branches of the family are negative for the variant protein. That the occurrence in serum of TTR-Met111 precedes the onset of clinical amyloid cardiomyopathy by several decades makes the variant TTR a marker for the disease. The distribution of afflicted family members and seropositivity for the variant TTR shows an autosomal dominant mode of inheritance.

CLINICAL SIGNIFICANCE

The results make possible early detection of potential patients and provide tools for genetic counseling. Cardiac transplantation may provide a new therapeutic option.

Senile systemic amyloidosis: a clinico-pathological study of twelve patients with massive amyloid infiltration

Hearts from 12 patients, 82-92 years old, with immunohistochemically verified pronounced senile systemic amyloidosis, were studied postmortem. Sections from the left ventricle, atrioventricular and sinus nodes and atrioventricular bundle were studied using the light microscope. The weights of the hearts varied between 310 and 870 grams. In the studied parts of the conduction system, the amounts of amyloid were considerably smaller than in the surrounding myocardium. Clinical data were taken from available case records. Eight of the patients had a history of uncomplicated congestive heart failure, but only two had been in hospital with cardiac symptoms prior to their last admission. The electrocardiogram showed atrial fibrillation in nine cases, left bundle branch block in three, right bundle branch block in two and left anterior hemiblock in one. No evidence of atrioventricular dissociation was seen and, in no case, was death considered to be due to conduction disturbances. Amyloidosis was a contributing cause of death in 7 patients, while the remaining patients died of other diseases. Amyloidosis is rarely diagnosed before death and was not suspected during life in any of our patients.

Glycosaminoglycans in extracts of cardiac amyloid fibrils from familial amyloid cardiomyopathy of Danish origin related to variant transthyretin Met 111

We have previously demonstrated an association between secondary AA type amyloid fibrils and glycosaminoglycans (GAGs) in human liver. The present study was aimed at investigating whether a similar association could be demonstrated in isolated cardiac amyloid fibrils from a unique Danish family with amyloid cardiomyopathy related to variant transthyretin (TTR) with a single amino acid substitution of a methionin for leucine at position 111 (TTR Met 111). Using gel filtration and ion exchange chromatography, significant amounts of GAGs were detected in close association with purified myocardial amyloid fibrils, whereas only trace amounts of polysaccharides were present in the corresponding normal preparation. The GAGs were identified as 50% chondroitin sulfate, 33% heparin/heparan sulfate, and 17% hyaluronan. With the methods used the amyloid associated GAGs appeared as high molecular weight free polysaccharide chains, and not as part of intact proteoglycans (PGs) in the fibril extracts. We conclude that the association between purified amyloid fibrils and GAGs may be a general feature of amyloid deposits. Also, we suggest that the proportion of different GAGs in the amyloid deposits may depend both on the organ or tissues affected and the type of proteins making up the fibrils.

A mutation in apolipoprotein A-I in the Iowa type of familial amyloidotic polyneuropathy

Immunoblotting of isoelectric focusing gels of plasma and direct genomic DNA sequencing have been used to characterize a mutation in apolipoprotein A-I associated with the familial amyloidotic polyneuropathy originally described by Van Allen in an Iowa kindred. An arginine for glycine substitution in apolipoprotein A-I identified in the proband's amyloid fibrils was determined to be the result of a mutation of guanine to cytosine in the apolipoprotein A-I gene at the position corresponding to the first base of codon 26. Direct sequencing of genomic DNA of three affected individuals who died in the 1960s confirmed the inheritance of the disorder. Immunoblot analysis detected the variant apolipoprotein A-I in the proband's plasma and in several at-risk members of the kindred. In addition, allele-specific amplification by the polymerase chain reaction was used to detect carriers of the variant gene.

Hereditary amyloidosis: detection of variant prealbumin genes by restriction enzyme analysis of amplified genomic DNA sequences

The autosomal dominant prealbumin amyloidoses are late-onset disorders characterized by varying degrees of peripheral neuropathy, nephropathy and cardiomyopathy. To date, seven different single amino acid mutations in the plasma protein prealbumin (transthyretin) have been found to be associated with amyloidosis and each is the result of a single nucleotide change in the prealbumin gene. By virtue of the restriction endonuclease sites created by the point mutations which give rise to the protein variants, direct DNA tests using Southern analysis have already been developed for detection of the Met-30, Ile-33, Ala-60, Tyr-77 and Ser-84 prealbumin genes. As an alternative to Southern analysis, we have amplified discrete regions of the prealbumin gene using polymerase chain reaction (PCR) and used restriction enzyme analysis of the PCR products to detect the Met-30, Ala-60, Tyr-77 and Ser-84 prealbumin genes after agarose gel electrophoresis and staining with ethidium bromide. In comparison to Southern analysis these alternative tests yield results much more quickly and avoid the use and handling of radioactively labeled probes.

Amyloidosis of the nervous system

Various types of amyloid fibril deposits occur in the nervous system with unique clinical characteristics and pathogeneses. Genetic mutations cause the familial amyloidotic polyneuropathies and acquired polyneuropathies occurring particularly in patients suffering from hypernephromas and myelomas also result from the production of abnormal proteins. Amyloid fibril deposits in cerebral plaques and vessels consisting of beta-protein are seen in acquired and familial Alzheimer's disease and in Down's syndrome individuals over 40 years of age. This amyloid fibril deposition could result from a mutational, transcriptional or post-translational alteration in these pathologic processes with most evidence supporting the latter. Other diseases including hereditary cerebral hemorrhage of the Dutch type and Batten's disease involve beta-amyloid deposition. The features of the familial and transmissible forms of the spongiform encephalopathies are associated with the prion protein which comprises the amyloid fibril deposits in these conditions. This wide variety of nervous system disorders having amyloid deposits as their primary or subsidiary characteristic make studies of these conditions intriguing models for research workers in clinical, pathologic and molecular biologic fields.

Systemic senile amyloidosis. Identification of a new prealbumin (transthyretin) variant in cardiac tissue: immunologic and biochemical similarity to one form of familial amyloidotic polyneuropathy

Isolated amyloid fibrils from three cases of systemic senile amyloidosis (SSA) contained subunit proteins with molecular masses of 14 (10-20%), 10-12 (60-80%), and 5-6 kD (5-10%) when fractionated under reducing and dissociating conditions. This grouping was identical to that seen in SKO, a case of familial amyloidotic polyneuropathy (FAP) studied earlier. Amino acid sequencing confirmed that SSA subunit proteins were in fact prealbumin (transthyretin). Complete sequence analysis of one SSA preparation revealed the presence of a new variant Pa (TTr) molecule with a single amino acid substitution of isoleucine for valine at position 122. Further studies used an antiserum specific for SKO IV, a subunit protein of SKO previously shown to correspond to carboxy-terminal 78 residues (positions 49-127) of (TTr). Anti-SKO IV reacted with SSA in tissue at equivalent dilutions to anti-Pa (TTr) and with the 10-12-kD fraction of SSA on Western blots; reactivity was blocked by SKO IV, but not by Pa (TTr). SSA is a form of systemic amyloidosis caused by tissue deposition of Pa (TTr) and its fragments, with shared conformational or subunit antigenicity to at least one form of FAP. Identification of a new variant Pa (TTr) molecule in one case suggests further that SSA may be a genetically determined disease expressed late in life.

Familial amyloidotic polyneuropathy

Amyloidosis has received considerable attention recently because of its association with Alzheimer's disease. Actually, the amyloid in the cortical plaques, which is characteristic of Alzheimer's disease, is a localized form of amyloid deposition. Although intracranial vascular amyloid deposits which contain the A4 or beta-protein are usually associated with Alzheimer's disease, deposition of this amyloid fibril substance in other organs of the body has not been described. Much less attention has been paid to amyloid involvement of the PNS which is a fascinating subject in itself and is the subject of this review.

The clinical and biochemical spectrum of hereditary amyloidosis

Familial amyloidosis, once described as a puzzling and highly unusual form of polyneuropathy, is now recognized to be a collection of familial diseases with usually autosomal-dominant inheritance and widespread ethnic distribution. Familial amyloidosis occurs throughout the world and encompasses an extremely broad spectrum of clinical manifestations. In some families, progressive peripheral neuropathy dominates the illness, while in others, renal failure, ocular amyloid deposits, cardiac decompensation, or intracranial hemorrhage is the most significant clinical feature. The Portuguese (type I) and the Iowa (type III) neuropathies characteristically begin with lower limb involvement, while in the Indiana (type II) form, upper limb neuropathy is seen first; in the Japanese families with familial amyloid polyneuropathy, symptoms first become evident around age 40, whereas in the Texas family, onset is in the seventh decade. The prognosis for the different families is highly variable. Current classification of the familial amyloid polyneuropathy syndromes is based on their characteristic clinical presentations, but ongoing biochemical identification of the protein composition of amyloid substance in each form will make a more rational nosology feasible in the near future. To date, no therapy has been shown to arrest or reverse the progressive accumulation of amyloid deposits in most forms of familial amyloidosis. Familial Mediterranean fever is a major exception, and the incidence of amyloidosis associated with this disease has been dramatically reduced by the widespread prophylactic use of colchicine. Technology currently available permits the reliable identification of asymptomatic relatives at risk for developing amyloid neuropathy as well as the prenatal identification of carriers of the mutant transthyretin gene. These strategies can be used in genetic counseling aimed at reducing the continued propagation of the mutant gene.

Familial atrial standstill caused by amyloidosis

Three of nine siblings were affected by atrial standstill. Clinical, electrophysiological, and histological findings in two of these cases were studied. Electrophysiological studies showed persistent atrial standstill in one and partial atrial standstill in the other. Biopsy specimens of the right atria showed amyloid deposits, but specimens of the right ventricles and skin did not. Neither patient had peripheral neuropathy, gastrointestinal disorder, or renal dysfunction. Familial atrial standstill is usually associated with peripheral neuropathy. In the two cases studied amyloid deposition mainly affected the atrium, rather than the ventricles or other organs, and caused atrial standstill.

A new prealbumin variant in familial amyloid cardiomyopathy of Danish origin

A C-terminal fragment of a prealbumin variant was isolated from amyloid material obtained from the myocardium of a patient (Han) with familial amyloid cardiomyopathy of Danish origin. The prealbumin variant fragment was shown to have a methionine for leucine substitution in position 111.

Primary hereditary systemic amyloidosis (Meretoja's syndrome): clinical features and treatment by plastic surgery

The characteristic, bloodhound-like appearance, which degenerates gradually, of patients with primary hereditary systemic amyloidosis, also called Meretoja's syndrome (MS), is attributable to amyloid degeneration of the craniofacial skin and peripheral facial nerves, but apparently also to amyloid deposits in the muscles; a finding not previously described. A material of five patients treated with plastic surgery is presented, and the peculiarities and differences of this rare disease in comparison with other peripheral neuropathies is discussed from a reconstructive viewpoint.

Onset in the seventh decade and lack of symptoms in heterozygotes for the TTRMet30 mutation in hereditary amyloid neuropathy-type I (Portuguese, Andrade)

In a Portuguese-American family with hereditary amyloid neuropathy (familial amyloidotic polyneuropathy), onset was in the seventh decade in all affected relatives. Another unusual characteristic was their origin from the Portuguese island of Madeira. In spite of this, the mutant transthyretin (TTRMet30) (the same variant prealbumin that is the circulating precursor of AFP protein in the classic Portuguese patients) could be found in the propositus' plasma. In addition, three other asymptomatic relatives (ages 90, 73, and 48) were shown to carry the mutation. Late onset and incomplete penetrance, at a clinical level, raise problems for presymptomatic detection of mutant TTR, as these tend to cluster in families. When counseling asymptomatic heterozygotes, we must consider intra-familial correlation in age-of-onset, and the distribution of age-of-onset including age of unaffected heterozygotes. This family poses interesting questions regarding pathogenesis of this degenerative process and the influence of other genetic factors, such as modifiers, epistasis, and polymorphism of the TTR genes or their regulators. A cis-effect of a gene linked to the mutant gene, decreasing the synthesis of the mutant TTR and keeping a sufficient amount of the normal one in circulation, or producing some cofactor for TTR, could also explain late onset and apparently incomplete penetrance; the occasional finding of classic forms in these families would be the result of recombinatory events.

Characterization of a transthyretin (prealbumin) variant associated with familial amyloidotic polyneuropathy type II (Indiana/Swiss)

Amyloid fibrils were isolated from cardiac tissue of two brothers who died from familial amyloidotic polyneuropathy (FAP) type II. Sequence analysis on peptides derived from proteolytic cleavage with trypsin and fragmentation with cyanogen bromide reveal that the fibril subunit protein is derived from plasma transthyretin (prealbumin). About two-thirds of the fibril subunit protein was found to contain an amino acid substitution at position 84 where the normal isoleucine residue has been replaced by serine. Sequence analysis of the plasma transthyretin (prealbumin) from the two brothers as well as two clinically diagnosed FAP type II family members and two of four children of affected individuals showed the presence of serine at position 84. The presence of this substitution also correlates with low serum levels of retinol-binding protein and thus transthyretin (prealbumin) position 84 may be involved with the interaction of these two proteins.

Primary amyloidosis (AL) in families

We report the occurrence of immunoglobulin-related amyloidosis (AL) in three separate families, each family having two members affected. None of the six patients had evidence to suggest the presence of familial amyloidosis (AF). Previously, immunoglobulin-related amyloidosis (AL) was considered to be a sporadic disease process. Because of the occasional familial occurrence of other monoclonal gammopathies such as monoclonal gammopathy of undetermined significance, multiple myeloma, and macroglobulinemia of Waldenström, amyloidosis (AL) should be added to the list of immunopathies with a familial predisposition.

The heart in Portuguese amyloidosis

A systematic investigation was performed in patients with familial amyloidotic polyneuropathy, Portuguese type (AFp) to assess the pattern and incidence of cardiac involvement. Of 327 patients investigated, ECG abnormalities were present in 285 (87.2%). Low voltage and QS pattern in V1, V2, V3 were found in 51.3% and 35.7% patients respectively. Conduction disturbances were present in 211 (64.5%). Sinus node disease, 1st degree and Wenckebach interventricular blocks were frequent. Complete atrioventricular block was observed in only 2 patients (0.6%). Left anterior hemi-block was present in 30.8%, left bundle branch block in 3.9%, left posterior hemi-block in 2.4% and right bundle branch block in 2.1%. Holter monitoring showed a much higher incidence of conduction disturbances, most of these occurring at night. The mean values of septum and posterior wall thickness and mass evaluated by echocardiography in 72 patients were normal. The systolic and diastolic global and regional functions, determined in 12 patients, analysing the echo by a digitization computer technique, were normal. In 7% a trivial pericardial effusion was observed. In 16 patients with ECG changes and normal echocardiograms the technetium 99m pyrophosphate scanning was negative. We conclude that the ECG is the most precise, sensitive and clinically useful method for detecting cardiac amyloidosis in patients with AFp. In spite of the rarity of congestive and restrictive patterns, the incidence and severity of conduction disturbances does not allow us to consider heart disease in AFp as a benign entity.

Amyloid deposits in aortic and mitral valves. A clinicopathological investigation of material from 100 consecutive heart valve operations

The material from 100 consecutive aortic and mitral valve operations has been studied histologically with particular reference to the presence of amyloid deposits. Sixty seven per cent were positive (aortic 88%, mitral 45%). The simultaneous occurrence of calcification of the valves and amyloid degeneration as well as of calcification and hyalinization was significant. Similarly there was significantly more amyloid in the older age groups, as well as a significant correlation between the degree of hyalinization of the valve and amyloid. Thirty-two patients had previously suffered from rheumatic fever. The heart valves of these patients did not differ histologically from the others, whereas significantly more amyloid was observed in the stenotic mitral valves than in the mitral valves which were insufficient.

Two dimensional echocardiographic similarity of Fabry's disease to cardiac amyloidosis: a function of ultrastructural analogy?

A 53-year-old man with Fabry's disease was studied by echocardiography. Both M-mode and two dimensional echocardiographic examinations produced findings indistinguishable from those previously described as virtually diagnostic of cardiac amyloidosis. Possible causes for the "granular sparkling" appearance and clinical implications of the similarities were discussed.

The cardiac atrioventricular conduction system in familial amyloidosis with polyneuropathy. A clinico-pathologic study of six cases from Northern Sweden

Cardiac conduction disturbances are frequent in amyloidosis with cardiac involvement, but the pathogenesis of these electrocardiographic abnormalities is not clear. In the present study, the conduction systems in six patients with the Swedish variety of familial amyloidosis with polyneuropathy (FAP), have been analyzed. The results suggest that in FAP, direct amyloid infiltration of the atrioventricular conduction system accounts for the majority of the electrocardiographic disturbances.

Microscopic amyloid deposits in the heart valves: a common local complication of chronic damage and scarring

The presence of amyloidosis was detected in 33 out of 213 (15.5%) mitral and aortic valves that had been surgically removed for chronic valvular disease. No correlation could be found with age or type of valvular disease, neither was there any clinical evidence of an associated generalised amyloidosis. Histologically, the amyloid deposits were microscopic and restricted to areas of dense scar tissue. No comparable alterations were found in 147 unaltered valves which served as controls. The term 'dystrophic' is proposed to describe this particular form of valvular amyloidosis.

Noninvasive cardiovascular findings in familial amyloid polyneuropathy

The cardiovascular system was examined in 19 cases of familial amyloid polyneuropathy. In a group of patients with neurological involvement, various cardiac abnormalities were common, including orthostatic hypotension, prominent apex cardiographic A waves, abnormal apical systolic waves (bulges), systolic murmurs, mid-systolic clicks, QS waves, atrioventricular block, left bundlebranch block, and abnormalities of ejection time and pre-ejection period. Though there was one case with pronounced cardiac abnormality despite a normal neurological state, and though cardiovascular symptoms appeared later than neurological symptoms, the degree of cardiac involvement generally paralleled the severity of the neurological disorder.

Cardiac amyloidosis in hereditary neuropathic amyloidosis diagnosed by endomyocardial biopsy

A 57 year old male first developed progressive neuropathy of the lower extremities and then similar involvement in the upper extremities. Two years later he developed dyspnea and then complete atrioventricular block requiring the use of a permanent cardiac pacemaker. An older brother had an almost identical clinical course, including the installation of a permanent pacemaker. Both died of left ventricular failure. An endomyocardial biopsy revealed extensive amyloidosis and fibrosis of the myocardium. This is the first report of a myocardial biopsy showing amyloid on electron microscopy.