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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.

Untargeted metabolomics is a well-established technique and a powerful tool to find potential plasma biomarkers for early diagnosing hereditary transthyretin amyloidosis. Hereditary transthyretin amyloidosis (ATTRv) is a disabling and fatal disease with different clinical features such as polyneuropathy, cardiomyopathy, different gastrointestinal symptoms and renal failure. Plasma specimens collected from 27 patients with ATTRv (ATTRV30M), 26 asymptomatic TTRV30M carriers and 26 control individuals were subjected to gas chromatography (GC)- and liquid chromatography (LC)-mass spectrometry (MS)-based metabolomics analysis. Partial least squares discriminant and univariate analysis was used to analyse the data. The models constructed by Partial least squares-discriminant analysis (PLS-DA) could clearly discriminate ATTRV30M patients from controls and asymptomatic TTRV30M carriers. In total, 24 plasma metabolites (VIP > 1.0 and p <.05) were significantly altered in ATTRV30M patient group (6 increased and 18 decreased). Eleven of these distinguished the ATTRV30M group from both controls and TTRV30M carriers. Plasma metabolomics analysis revealed marked changes in several pathways in patients with ATTRV30M amyloidosis. Statistical analysis identified a panel of biomarkers that could effectively separate controls/TTRV30M carriers from ATTRV30M patients. These biomarkers can potentially be used to diagnose patients at an early stage of the disease.

Introduction: Hereditary transthyretin (ATTRv) amyloidosis is of autosomal dominant transmission, caused by a spectrum of mutations in the transthyretin (TTR) gene. The ATTRV30M (p.Val50Met) is the most frequent substitution in Europe. Northern Sweden is a known cluster for ATTRV30M amyloidosis patients due to high prevalence of the mutation rate, with homozygous cases. First symptoms occur generally during the 6th decade. Previous studies reported low penetrance in this area and possible anticipation in families. In order to refine our knowledge of the genetic aspects, penetrance and factors that influence the disease’s risk, we performed a comprehensive study of ATTRV30M families in Sweden.

Methods: To assess anticipation, well-established age at onset (AO) was compared in all informative parent-offspring pairs and in subgroups, after excluding ascertainment biases. Penetrance was estimated using a non-parametric method that enables to study covariates’ effect on the disease’s risk.

Results: We analysed 114 ATTRV30M Swedish families, including 12 homozygous individuals. Among 131 parent-offspring pairs, we found an average anticipation of 11.7 [Standard Deviation (SD) =10.03] years, higher in case of maternal transmission (mean ± SD = 13.7 ± 8.4 years), compared to paternal transmission (mean ± SD = 7.9 ± 11.5 years, p < .003). Anticipation remained significant, after exclusion of ascertainment biases. In heterozygous ATTRV30M kindred, penetrance was low, estimated below 10% [95% confidence interval (CI) = 6–10] at 40 years-old, increasing to 71% [95% CI= 65–76] at age 90 years. The risk was found to be higher in male patients (p < .01) and in case of maternal transmission (p < .01), reflecting a parent of origin effect. We observed no difference of penetrance according the geographical origin. Finally, the disease risk was similar in heterozygous and homozygous ATTRV30M amyloidosis individuals.

Conclusions: Our study provides new data on the genetics of ATTRV30M families in Sweden, including the occurrence of anticipation and on penetrance. Both are increased in case of maternal inheritance and in male patients. Overall, gender seems to be a factor that substantially modulates the AO of the disease, in this area. Clinically, these findings are of importance to guide the management of sibships and the monitoring of mutation carriers.

For the first time, we report of a Swedish family of five individuals with a TTR Glu54Leu (p. Glu74Leu) mutation in the transthyretin gene. This mutation has been previously described a few times in the literature, but no phenotypic or clinical description has been done before. The most common mutation in the Swedish population is TTRVal30Met and is mostly found in the Northern part of Sweden. Interestingly, the TTRGlu54Leu mutation was found in the same endemic area. The main phenotype of the TTR Glu54Leu patients is severe cardiomyopathy, which resulted in heart transplantation for the index person. As previously seen for ATTR amyloidosis patients with mainly cardiomyopathy, the amyloid fibrils consisted of a mixture of full-length and fragmented TTR species. However, western blot analyses detected a previously unrecognized band, indicating that these patients may have a third, so far unrecognized, fibril composition type that is distinct from the usual type A band pattern.

In genetic diseases with variable age of onset, survival function estimation for the mutation carriers as well as estimation of the modifying factors effects are essential to provide individual risk assessment, both for mutation carriers management and prevention strategies. In practice, this survival function is classically estimated from pedigrees data where most genotypes are unobserved. In this article, we present a unifying Expectation-Maximization (EM) framework combining probabilistic computations in Bayesian networks with standard statistical survival procedures in order to provide mutation carrier survival estimates. The proposed approach allows to obtain previously published parametric estimates (e.g. Weibull survival) as particular cases as well as more general Kaplan-Meier non-parametric estimates, which is the main contribution. Note that covariates can also be taken into account using a proportional hazard model. The whole methodology is both validated on simulated data and applied to family samples with transthyretin-related hereditary amyloidosis (a rare autosomal dominant disease with highly variable age of onset), showing very promising results.

Objective: Refine estimation of penetrance in TTR-FAP families, unravelling the role of covariates. Background: TTR-FAP is an autosomal dominant neuropathy caused by mutations in the TTR gene. Recently, therapeutic advances including gene modifying approaches proved effective to halt disease progression. Val30Met, the most common variant in Portugal and Latin America is associated to age at onset (AO) below 50 y-o. In Western Europe, US, Japan, heterogeneity of TTR variants is associated to AO above 50 y-o, a mixed polyneuropathy and cardiomyopathy. Determining the risk of being affected (penetrance) is essential to guide gene carrier management.

Design/Methods: NPSE is a non-parametric method developed to estimate penetrance, taking into account covariates. Genealogical data from 227 kindreds were collected. There were 92 Val30Met families from Sweden, 64 Val30Met from Portugal and 73 from France including 37 Val30Met and 36 families carrying other TTR variants frequently identified: Ser77Tyr (15), Ile107Val (12), Ser77Phe (9).

Results: We found highly significant differences of penetrance between Val30Met families from various origins. Risk estimates also differed between the TTR variants (French Val30Met, Ser77Tyr, Ile107Val, Ser77Phe) (p < 0.004). In the French and Swedish Val30Met families, the disease risk remained below 10% until age 40 years then increased to 72% and 63% at 80 years, respectively. In Portuguese families, the risk was above 20% from age 30 years then up to 92% at 80 y-o. In Ile107Val, Ser77Tyr and Ser77Phe families the risk was virtually null until 50 years of age and raised to 54%, 70%, and 86% at age 80 years, respectively. A higher risk is observed when the disease is maternally inherited in Portuguese and Swedish kindreds (p <0.001).

Conclusions: Important variation of penetrance is observed in TTR-FAP families according covariates. Such data will help for management of gene carriers, allowing early diagnosis and therapeutic initiation timely.

Doxycycline has been shown to disrupt transthyretin amyloid (ATTR) fibrils [1] and tauro-ursodeoxycholic acid (TUDCA) has been shown to reduce TTR toxic aggregates in mice [2]. Further, in 2010 Cardoso et al. showed that a combined doxycycline/TUDCA treatment had a synergistic effect, decreasing ATTR deposition. Ursodeoxycholic acid (UDCA) is a bile acid used for the treatment of certain cholestatic syndromes with an efficacy similar to that of TUDCA. Based on this knowledge, we wanted to explore if treatment with doxycycline and UDCA (Dox/Urso) would prevent disease progression in ATTR amyloidosis. UDCA was selected since TUDCA is not available in Sweden.

By genotyping a large number of samples from the Northern Sweden Health and Disease Study cohort, a carrier frequency could be determined for the Skelleftea and Lycksele populations. A previous study of the amyloidogenic transthyretin mutation TTRV30M in Northern Sweden's endemic area has shown a large variation in carrier frequency and penetrance of the trait within the area. However, the estimations have been based on a small sample size within the different regions in the area and therefore, the wide variation in TTRV30M carrier frequency observed between the Lycksele and Skelleftea populations are uncertain. Based on a total of 3460 samples, the estimated overall carrier frequency in the two regions was 1.82% with a carrier frequency in the Skelleftea and Lycksele population of 1.63% and 2.02%, respectively. Thus, the previously reported extremely high frequency in the Lycksele region compared to that of the Skelleftea region could not be substantiated. However, it does not change the previous finding of a surprisingly higher carrier frequency in the population from endemic area of Northern Sweden compared to that reported from endemic areas in Portugal.

Introduction: Hereditary transthyretin amyloidosis (ATTR) is a genetic disease caused by a point mutation in the TTR gene that causes the liver to produce an unstable TTR protein. The most effective treatment has been liver transplantation in order to replace the variant TTR producing liver with one that produces only wild-type TTR. ATTR amyloidosis patients' livers are reused for liver sick patients, i.e. the Domino procedure. However, recent findings have demonstrated that ATTR amyloidosis can develop in the recipients within 7-8 years. The aim of this study was to elucidate how the genetic profile of the liver is affected by the disease, and how amyloid deposits affect target tissue. Methods: Gene expression analysis was used to unravel the genetic profiles of Swedish ATTR V30M patients and controls. Biopsies from adipose tissue and liver were examined. Results and Conclusions: ATTR amyloid patients' gene expression profile of the main source organ, the liver, differed markedly from that of the controls, whereas the target organs' gene expression profiles were not markedly altered in the ATTR amyloid patients compared to those of the controls. An impaired ER/protein folding pathway might suggest ER overload due to mutated TTR protein.

Background: Hereditary transthyretin (TTR) amyloidosis (ATTR) is an autosomal dominant disease characterized by extracellular deposits of amyloid fibrils composed of misfolded TTR. The differences in penetrance and age at onset are vast, both between and within populations, with a generally late onset for Swedish carriers. In a recent study the entire TTR gene including the 3' UTR in Swedish, French and Japanese ATTR patients was sequenced. The study disclosed a SNP in the V30M TTR 3' UTR of the Swedish ATTR population that was not present in either the French or the Japanese populations (rs62093482-C > T). This SNP could create a new binding site for miRNA, which would increase degradation of the mutated TTR's mRNA thus decrease variant TTR formation and thereby delay the onset of the disease. The aim of the present study was to disclose differences in allele specific TTR expression among Swedish V30M patients, and to see if selected miRNA had any effect upon the expression.

Methodology/Principal Findings: Allele-specific expression was measured on nine liver biopsies from Swedish ATTR patients using SNaPshot Multiplex assay. Luciferase activity was measured on cell lines transfected with constructs containing the TTR 3' UTR. Allele-specific expression measured on liver biopsies from Swedish ATTR patients showed no difference in expression between the two alleles. Neither was there any difference in expression between cell lines co-transfected with two constructs with or without the TTR 3' UTR SNP regardless of added miRNA.

Conclusions/Significance: The SNP found in the 3' UTR of the TTR gene has no effect on degrading the variant allele's expression and thus has no impact on the diminished penetrance of the trait in the Swedish population. However, the 3' UTR SNP is unique for patients descending from the Swedish founder, and this SNP could be utilized to identify ATTR patients of Swedish descent.