Familial amyloid polyneuropathy related to transthyretin mutation VaL30 to Leu in a Japanese family

A rare variant transthyretin that has a leucine-for-valine substitution at position 30 was reported in a sporadic case of type 1 familial amyloid polyneuropathy (FAP). We found the same substitution in members of a Japanese family with FAP. Three individuals in this family had a guanine-to-cytosine mutation at the first base of codon 30 in exon 2. This family shows a direct link between a valine-to-leucine substitution at position 30 and type 1 FAP. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21: 1783–1785, 1998     

A novel ATTR L32V mutation causes familial amyloid polyneuropathy in a Bolivian family

We report a new transthyretin (ATTR) gene c.272C>G mutation and variant protein, p.Leu32Val, in a kindred of Bolivian origin with a rapid progressive peripheral neuropathy and cardiomyopathy. Three individuals from a kindred with peripheral nerve and cardiac amyloidosis were examined. Analysis of the TTR gene was performed by Sanger direct sequencing. Neuropathologic examination was obtained on the index patient with mass spectrometry study of the ATTR deposition. Direct DNA sequence analysis of exons 2, 3, and 4 of the TTR gene demonstrated a c.272 C>G mutation in exon 2 (p.L32V). Sural nerve biopsy revealed massive amyloid deposition in the perineurium, endoneurium and vasa nervorum. Mass spectrometric analyses of ATTR immunoprecipitated from nerve biopsy showed the presence of both wild‐type and variant proteins. The observed mass results for the wild‐type and variant proteins were consistent with the predicted values calculated from the genetic analysis data. The ATTR L32V is associated with a severe course. This has implications for treatment of affected individuals and counseling of family members.     

Rapidly progressive amyloid polyneuropathy associated with a novel variant transthyretin serine 25

We report a 52-year-old woman with a novel transthyretin (TTR) variant serine replacing alanine at residue 25 [Ala25Ser (Serine 25)], who showed a unique clinical picture with a relatively acute onset neuropathy within a few days of an influenza vaccination, progressing to a severe degree within 2 years. Sural nerve biopsy revealed amyloid deposition in the endoneurium. Sequencing of the proband's DNA revealed a G to T transversion at the first position of codon 25 of TTR gene. DNA analysis of this family showed the same mutation in her older sister and a niece, but her parents did not have the mutation. Haplotype analysis revealed the mutation to be clearly linked to haplotype III allele inherited from the proband's father. These results indicate this novel Serine 25 mutation originated in the paternal germline mosaicism. It is possible that the vaccination had an influence on the unique clinical picture, but this remains uncertain.     

An aggressive form of familial amyloid polyneuropathy caused by a Glu54Gly mutation in the transthyretin gene

We report a patient with familial amyloid polyneuropathy. Gene analysis revealed a heterozygous Glu54Gly substitution (A-to-G change) in the transthyretin gene. This is the first case of a Glu54Gly substitution that was devoid of a Gly6Ser substitution. Compared with the previously reported case with compound heterozygotes of Glu54Gly and Gly6Ser, the age of onset in our case is much younger and another characteristic findings were the amyloid vasculopathy and the multiple organ involvement. A Glu54Gly mutation is amyloidogenic by itself and a Gly6Ser mutation may offer some protection from the Glu54Gly mutant.     

Electrophysiological features of late-onset transthyretin Met30 familial amyloid polyneuropathy unrelated to endemic foci

BACKGROUND : Through the development of gene diagnostic techniques, late-onset transthyretin Met30-associated familial amyloid polyneuropathy (FAP TTR Met30) has been shown to be more prevalent than is generally believed. OBJECTIVE : To examine the electrophysiological features of late-onset FAP TTR Met30 unrelated to endemic foci. METHODS : Nerve conduction findings in 44 cases with an onset of more than 50 years of age in a non-endemic area were assessed and compared with findings from 21 earlier-onset cases related to endemic foci. RESULTS : The extent of the reduction of the compound muscle action potential and, especially, the sensory nerve action potential was more profound in the late-onset group even when the decline of these indices with aging in normal control subjects was taken into account. The feature of predominant lower-limb involvement seemed to be more conspicuous in the late-onset group. Electrophysiological indices tended to be aggravated as the duration of neuropathic symptoms increased in the early-onset group, while most of these indices in the lateonset group did not show this correlation. A slowing of conduction velocity and a prolongation of distal latency, which suggests demyelination, were conspicuous in some patients. Pathologically, a predominant loss of small-fibers was not conspicuous in sural nerve biopsy specimens from late-onset patients. Large myelinated fiber density showed a negative correlation with the disease duration in early-onset cases, but not in late-onset cases. CONCLUSIONS : Electrophysiological differences between late- and early-onset cases were present, probably reflecting the different underlying pathogenic mechanisms of neuropathy. The demyelinating feature does not exclude the possibility of this disease.     

Estimating the global prevalence of transthyretin familial amyloid polyneuropathy

Introduction: This study sought to estimate the global prevalence of transthyretin familial amyloid polyneuropathy (ATTR‐FAP). Methods: Prevalence estimates and information supporting prevalence calculations was extracted from records yielded by reference‐database searches (2005–2016), conference proceedings, and nonpeer reviewed sources. Prevalence was calculated as prevalence rate multiplied by general population size, then extrapolated to countries without prevalence estimates but with reported cases. Results: Searches returned 3,006 records; 1,001 were fully assessed and 10 retained, yielding prevalence for 10 “core” countries, then extrapolated to 32 additional countries. ATTR‐FAP prevalence in core countries, extrapolated countries, and globally was 3,762 (range 3639–3884), 6424 (range, 1,887–34,584), and 10,186 (range, 5,526–38,468) persons, respectively. Discussion: The mid global prevalence estimate (10,186) approximates the maximum commonly accepted estimate (5,000–10,000). The upper limit (38,468) implies potentially higher prevalence. These estimates should be interpreted carefully because contributing evidence was heterogeneous and carried an overall moderate risk of bias. This highlights the requirement for increasing rare‐disease epidemiological assessment and clinician awareness. Muscle Nerve 57 : 829–837, 2018     

Management of asymptomatic gene carriers of transthyretin familial amyloid polyneuropathy

Transthyretin familial amyloid polyneuropathy (TTR‐FAP) is a rare, severe, and irreversible, adult‐onset, hereditary disorder caused by autosomal‐dominant mutations in the TTR gene that increase the intrinsic propensity of transthyretin protein to misfold and deposit systemically as insoluble amyloid fibrils in nerve tissues, the heart, and other organs. TTR‐FAP is characterized by relentless, progressively debilitating polyneuropathy, and leads to death, on average, within 10 years of symptom onset without treatment. With increased availability of disease‐modifying treatment options for a wider spectrum of patients with TTR‐FAP, timely detection of the disease may offer substantial clinical benefits. This review discusses mutation‐specific predictive genetic testing in first‐degree relatives of index patients diagnosed with TTR‐FAP and the structured clinical follow‐up of asymptomatic gene carriers for prompt diagnosis and early therapeutic intervention before accumulation of substantial damage. Muscle Nerve 54 : 353–360, 2016     

Variable presentations of TTR-related familial amyloid polyneuropathy in seventeen patients

Autosomal-dominant transthyretin (TTR)-related amyloidosis usually manifests in the second to fourth decade with a length-dependent axonal neuropathy with prominent involvement of the small fibers and multi-organ systemic failure. We retrospectively analyzed seventeen probands, including thirteen apparently isolated cases, carrying eight mutations of TTR gene (age of onset = 60.4 ± 13.5 years). Thirteen patients were initially un/misdiagnosed; interval from onset to definite diagnosis was 3.3 ± 2.3 years. Inaugural syndromes were a length-dependent motor-sensory neuropathy in seven cases, a sensory neuropathy in four, an isolated carpal tunnel syndrome in three, a pure dysautonomia in two, and a painful neuropathy in one. Atypical presentations included demyelinating nerve conduction changes with increased cerebrospinal fluid proteins resembling chronic inflammatory demyelinating polyradiculoneuropathy and a predominantly motor involvement resembling a motor neuron disorder. Misleading findings also included amyloid-negative abdominal fat aspirate/biopsy, biclonal gammopathy, and hepatitis C virus (HCV) seropositivity. Sural nerve biopsy detected amyloid deposits in thirteen of fifteen patients, including one case with a previous negative biopsy. TTR-immunohistochemistry was necessary to complete the diagnosis of primary amyloidosis light chain in a patient with biclonal gammopathy. A recurrent p.Phe64Leu mutation manifested in the seventh decade with painful motor-sensory polyneuropathy, dysautonomia, bulbar palsies, and fasciculations. TTR should be tested in a wide clinical spectrum of cryptogenetic, progressive, and motor-sensory neuropathies even manifesting with a very late onset.     

Familial amyloid polyneuropathy in Taiwan: Identification of transthyretin variant (Leu55 → Pro)

We report a family with familial amyloid polyneuropathy (FAP), showing an early-onset and a fatal outcome before age 30. Transthyretin (TTR) gene analysis showed one point mutation (T → C change) in the second base of codon 55, and the corresponding amino acid substitution of proline (Pro) for leucine (Leu) was confirmed at the protein level. This is the first FAP family of Taiwanese origin demonstrating a causative gene abnormality, and FAP with TTR-Pro⁵⁵ was considered to be more serious compared with other forms of FAP. © 1994 John Wiley & Sons, Inc.     

Amyloidogenic transthyretin Val30Met homozygote showing unusually early-onset familial amyloid polyneuropathy

We report an amyloidogenic transthyretin (ATTR) Val30Met homozygote showing extremely early-onset, severe familial amyloid polyneuropathy (FAP). Although homozygotes have been reported to show late-onset and mild clinical manifestations, detailed analyses of the present and previously reported families suggest that homozygotes have a slightly more severe clinical course than heterozygotes. This is the youngest reported patient with ATTR Val30Met FAP, a condition believed to be attributable to homozygosity of this mutation. The clinical severity is consistent with TTR protein instability.     

Familial amyloid polyneuropathy related to transthyretin Gly42 in a Japanese family.

A Japanese family is described in which 6 persons showed familial amyloid polyneuropathy (FAP). Mean ages of onset were 38 for 4 males and 54 for 2 females. Three of the 6 became emaciated and died after 4 to 10 years. In 5, muscular weakness and autonomic dysfunction were the initial symptoms followed by sensory disturbances. Amyloidotic cardiomyopathy was present in 3 of the subjects. Amyloid deposits showed an immunohistological relation to transthyretin (TTR). Analysis of 1 patient's TTR gene revealed a single base change (A----G) that led to amino acid substitution (Glu42----Gly). This base change produced a new restriction site for endonuclease Cfr13 I in exon 2. Polymorphic analysis of the length of the Cfr13 I-restriction fragment confirmed the base change, and made it possible to detect the mutant TTR Gly42 gene in the FAP subjects. Amino acid sequencing analysis showed a variant of TTR Gly42 in 1 patient's serum.     

四个TTR-FAP家系的临床特征分析

目的探讨转甲状腺素蛋白相关家族性淀粉样变性周围神经病(TTR-FAP)的临床特征。方法收集空军军医大学第一附属医院神经内科自2017年7月至2019年5月收治的4个TTR-FAP家系(包括20例TTR-FAP患者和2例无症状TTR突变基因携带者)的临床资料,并对其中4例先证者的临床资料进行详细分析。结果20例TTR-FAP患者的发病年龄为30~65岁,均以消化道症状为首发症状,存在不同程度的周围神经损害和体质量明显下降,以及心脏损害9例、体位性低血压9例、性功能障碍5例、排尿异常6例、瞳孔缩小或视物模糊3例,7例经TTR基因检测确诊、3例经腓肠神经病理活检明确,接受二氟尼柳治疗1例、氯苯唑酸治疗2例(病情均进展),死亡12例,存活8例。4例先证者均为男性,发病年龄平均49.3岁;均具有程度不等的感觉运动性周围神经病、自主神经病和心肌病表现;神经电生理检查提示长度依赖性的四肢感觉运动性周围神经病,以轴索损害为著;超声心动图示均有心肌肥厚;3例腓肠神经病理活检发现组织中刚果红染色均呈阳性;全外显子测序显示2例携带TTR基因致病性突变(TTR-E74K、TTR-A140S),1例携带可能致病性突变(TTR-S70R)。2例无症状TTR突变基因携带者仍正常。结论TTR-FAP在临床上表现为周围神经、自主神经持续进行性损害,同时累及多系统,尤其易合并消化道症状、心肌肥厚、体质量明显下降、瞳孔缩小或视物模糊,这些临床特征对该病的诊断有重要提示作用。     

ABO-incompatible auxiliary partial orthotopic liver transplant for late-onset familial amyloid polyneuropathy

A 60-year-old Japanese man with late-onset familial amyloid polyneuropathy type I (FAP transthyretin Met30) showed clinical improvement following auxiliary partial orthotopic liver transplantation (APOLT) from an ABO-incompatible living related donor. Preoperatively, plasmapheresis and immunosuppressant drugs were used to reduce serum antibodies against the donor's ABO type. APOLT was chosen so the residual liver could sustain the patient in the event of hyperacute rejection. OLT is applicable to late-onset FAP transthyretin Met30, and APOLT can be considered in ABO-incompatible cases.     

Muscular amyloid angiopathy with amyloidgenic transthyretin Ser50Ile and Tyr114Cys

Among patients with familial amyloid polyneuropathy (FAP), those with transthyretin Val30Met mainly show distally predominant weakness and atrophy, whereas some FAP patients, including those with transthyretin Ser50Ile and Tyr114Cys, show muscle weakness and atrophy that is dominant proximally, simulating myopathy. To clarify the cause of proximally dominant muscular atrophy in patients with FAP transthyretin Ser50Ile and Tyr114Cys, we investigated the distinctive features of muscle specimens of patients with FAP, 3 of who had Val30Met, 2 Ser50Ile, and 2 Tyr114Cys transthyretin. All specimens showed transthyretin amyloid around blood vessels and perimysium, and neurogenic denervation patterns. The amount of amyloid around the vessels was much greater in patients with FAP Ser50Ile and Tyr114Cys than in Val30Met patients. Muscular amyloid angiopathy may contribute to motor nerve injury that, in turn, may lead to amyotropic changes in patients with FAP Ser50Ile and Tyr114Cys.     

Norfolk QOL‐DN: validation of a patient reported outcome measure in transthyretin familial amyloid polyneuropathy

The Norfolk Quality of Life‐Diabetic Neuropathy (QOL‐DN) questionnaire is an instrument to assess QOL in diabetic polyneuropathy. The objective of this observational, cross‐sectional study in 61 patients with V30M transthyretin familial amyloid polyneuropathy (TTR‐FAP) and 16 healthy volunteers was to validate the Norfolk QOL‐DN for assessment of QOL in TTR‐FAP. Comparisons were conducted to identify the best items to discriminate disease stages and assess which individual Norfolk domains (symptoms, large fiber, small fiber, autonomic, and activities of daily living) would be most affected by disease stage. Analysis of individual items revealed a significant pattern of discrimination among disease stages (p < 0.001). Total QOL scores increased (indicating worsening) with duration of symptoms, with a steeper increase observed earlier in the course of disease. Significant correlations were observed between each Norfolk domain and other measures of neurological function. Limitations include cross‐sectional study design, low patient numbers in this rare disease, and the ordinal‐based character of the metric used; future areas to explore include item response theory approaches such as Rasch analysis. These results suggest the Norfolk QOL‐DN is a reliable indicator of the impact of disease severity on QOL in patients with TTR‐FAP.     

Familial amyloid polyneuropathy associated with transthyretin Gly42 mutation: a quantitative light and electron microscopic study of the peripheral nervous system

We performed extensive quantitative analyses of the peripheral nervous system (PNS) of two siblings with familial amyloid polyneuropathy (FAP) caused by a transthyretin (TTR) Gly42 mutation. Pronounced amyloid deposition was found in the sympathetic ganglia (SyG), dorsal root ganglia (DRG) and throughout the length of the peripheral nerve fibers with some accentuation in the more proximal portion. There was severe neuronal loss in the SyG and DRG together with nerve fiber depletion in the nerve trunk, while only a small amount of amyloid deposition with mild fiber loss was seen in the spinal roots. Sprouts of regenerating axons were very scanty even in the spinal nerves or roots. A teased fiber study mainly showed demyelinating fibers, but axonal degeneration was also present throughout peripheral nerves. An electron microscopic study showed fine amyloid fibrils in direct contact with the axoplasmic membrane of demyelinated axons and destruction of axons in some areas. Amyloid deposition within the PNS in this type of FAP resembled that in type I FAP (TTR Met30). However, direct axonal damage by amyloid fibrils appeared to be more prominent in our cases than in type I FAP. Lectin histochemistry using Ulex europaeus agglutinin I demonstrated preferential depletion of small neurons in the DRG and their primary afferent fibers in the spinal dorsal horn. Primary axonal degeneration and ganglionopathy due to amyloid deposition appear to be the pathogenetic mechanisms for peripheral neuropathy in this type of FAP.     

Genetics of familial amyloidotic polyneuropathy in a Hong Kong Chinese kindred

Familial amyloidotic polyneuropathy type 1 (FAP1, MIM176300) is an autosomal dominant disease caused by mutations in the transthyretin (TTR) gene. An extended Chinese kindred of FAP1 was first reported in Hong Kong in 1989, three of the four histologically proven subjects have deceased. TTR gene mutations were not studied then. A DNA-based diagnosis was performed on FAP1 by restriction analysis and direct DNA sequencing was carried out on a symptomatic member of this family who had undergone a liver transplantation. It showed a substitution of thymine by cytosine in the second base of codon 30 in exon 2 of the TTR gene, with the creation of a novel HhaI restriction endonuclease site. Valine is substituted by alanine (V30A) in the mutant TTR. Both restriction analysis and direct sequencing revealed the same mutation in one of the two asymptomatic siblings. This mutation was first reported in a FAP1 family of German descent.     

“Red‐flag” symptom clusters in transthyretin familial amyloid polyneuropathy

Transthyretin familial amyloid polyneuropathy (TTR‐FAP) is a rare, progressive, life‐threatening, hereditary disorder caused by mutations in the transthyretin gene and characterized by extracellular deposition of transthyretin‐derived amyloid fibrils in peripheral and autonomic nerves, heart, and other organs. TTR‐FAP is frequently diagnosed late because the disease is difficult to recognize due to phenotypic heterogeneity. Based on published literature and expert opinion, symptom clusters suggesting TTR‐FAP are reviewed, and practical guidance to facilitate earlier diagnosis is provided. TTR‐FAP should be suspected if progressive peripheral sensory‐motor neuropathy is observed in combination with one or more of the following: family history of a neuropathy, autonomic dysfunction, cardiac hypertrophy, gastrointestinal problems, inexplicable weight loss, carpal tunnel syndrome, renal impairment, or ocular involvement. If TTR‐FAP is suspected, transthyretin genotyping, confirmation of amyloid in tissue biopsy, large‐ and small‐fiber assessment by nerve conduction studies and autonomic system evaluations, and cardiac testing should be performed.     

New transthyretin mutation V28M in a Portuguese kindred with amyloid polyneuropathy

A 62-year-old Portuguese man, with no history of familial amyloid polyneuropathy (FAP), and a 2(1/2)-year history of tingling in the toes and sexual dysfunction was found neurophysiologically to have a sensory-motor axonal polyneuropathy. Autonomic tests showed slight sympathetic and marked parasympathetic involvement. Heart, kidney, and eyes were normal. Single strand conformation polymorphism (SSCP) mutation analysis for the transthyretin (TTR) gene was performed. The SSCP pattern suggested the presence of a mutation in exon 2, but was different from the pattern observed for a control representing the most common TTR mutation associated with FAP, i.e., TTR V30M. DNA sequencing analysis revealed an A-to-G transition in the first base of codon 28 normally encoding a valine, giving rise to a methionine residue. The presence of this extra methionine was confirmed by peptide mapping and mass spectrometry analysis. Biopsy of nerve and skin of the propositus showed amyloid deposits that were immunoreactive for TTR. This is a new variant TTR related to late-onset amyloid neuropathy with autonomic dysfunction. This case confirms that TTR mutation screening should be considered in patients with a clinical disorder consistent with amyloid neuropathy even in the absence of a family history.     

Familial amyloid polyneuropathy: alanine-for-threonine substitution in the transthyretin (prealbumin) molecule

A previously reported family with amyloid polyneuropathy (FAP) was reinvestigated to determine the type of mutation in the transthyretin (prealbumin) molecule. Transthyretin was isolated from amyloid-laden myocardium and serum, and tryptic peptides were resolved by high-performance liquid chromatography. Amino acid sequencing of an anomalous peptide revealed an alanine-for-threonine substitution corresponding to position No. 60 of the transthyretin monomer. Detection of the FAP gene in asymptomatic carriers was accomplished by hybrid isoelectric focusing of transthyretin in the presence of dithiothreitol and high concentrations of urea, and by Southern blotting of Pvull-digested leukocyte deoxyribonucleic acid. This type of FAP was found to be identical to the previously described Appalachian amyloid. Patients with FAP and their asymptomatic gene-carrying offspring had significantly reduced levels of serum transthyretin and retinol-binding protein.