Clinical comparison of V122I genotypic variant of transthyretin amyloid cardiomyopathy with wild-type and other hereditary variants: a systematic review

V122I genotype variant (pV142I) is the most common hereditary transthyretin amyloidosis (hATTR) in the USA, with 3–3.5% of African-Americans being the carriers of this mutation. We aimed to compare baseline clinical features, cardiac parameters, and mortality in V122I-ATTR with the wild-type ATTR and other hATTR subtypes. We systematically searched PubMed/Medline and Google Scholar databases to identify relevant studies from inception to 10th September, 2020 reporting phenotypic, echocardiographic, and/or laboratory parameters in patients with hereditary and wild types of cardiac amyloidoses. A total of 2843 patients from 7 individual studies with 67–100% males and an overall follow-up duration of 51.6 ± 30.4 months were identified. The mean age of diagnosis among wild-type ATTR patients was 77 years, followed by 71.2 and 65 years in V122I and T60A group patients, respectively. V122I patients were mostly black, had a poor quality of life, and highest mortality risk compared with other subtypes. Merely, the presence of V122I mutation was identified as an independent predictor of mortality. V30M subtype correlated with the least severe cardiac disease and a median survival duration comparable with T60A subtype. V122I ATTR is an aggressive disease, prevalent in African-Americans, and is associated with a greater morbidity and mortality, which is partly attributed to its misdiagnosis and/or late diagnosis. Current advances in non-invasive studies to diagnose hATTR coupled with concurrent drug therapies have improved quality of life and provide a survival benefit to these patients.