Restrictive cardiomyopathy in inherited ATTR amyloidosis (TTR-Ser23Asn) in a patient of German-Italian extraction

Rare variant (p.Ser43Asn) of familial transthyretin amyloidosis associated with isolated cardiac phenotype: A case series with literature review

Background

p.Ser43Asn is a very rare transthyretin (TTR) mutation leading to familial amyloidosis of transthyretin type, ATTR amyloidosis. It was previously observed in four patients worldwide and is associated almost invariably with an isolated cardiac phenotype.

Methods and Results

We report here on an Italian family with early‐onset cardiomyopathy and aggressive disease course in the affected individuals leading untreated to cardiac death before 55 years of age. We describe the clinical phenotype and imaging findings of two affected siblings, who were treated with tafamidis at an early disease stage, and their affected mother, who died 9 years ago due to refractory heart failure. The review of the available literature highlights the fact that until recently ATTR amyloidosis may have been misdiagnosed as other types of hypertrophic cardiomyopathy.

Conclusion

A better characterization of the genotype–phenotype associations is crucial to achieve optimal outcomes and facilitate informed decisions when treating individuals with rare mutations.

Technetium pyrophosphate myocardial uptake and peripheral neuropathy in a rare variant of familial transthyretin (TTR) amyloidosis (Ser23Asn): a case report and literature review

We report the fourth case of transthyretin amyloidosis (ATTR) Ser23Asn in a 41-year-old Ecuadorian male. He has a pedigree that spans seven generations and involves 24 family members who suffered early cardiac death. Salient presenting symptoms were fatigue, shortness of breath, and peripheral neuropathy. The diagnosis of cardiac amyloid was confirmed by immunohistochemical staining of an endomyocardial biopsy, genotyping and by technetium pyrophosphate ((99m)Tc-PYP) scintigraphy, which remains to be established as a reliable tool to visualize myocardial amyloid involvement in patients with the Ser23Asn transthyretin (TTR) variant. The patient underwent successful combined heart and liver transplant. We add to the current ATTR literature that in patients with the rare Ser23Asn mutation, peripheral nerve in addition to cardiac involvement can occur and (99m)Tc-PYP scintigraphy can be used as an imaging modality to visualize myocardial amyloid.