A novel mutation in the transthyretin gene in amyloidosis: A cluster case report in Vietnam

Transthyretin amyloidosis (ATTR) is a slowly progressive condition characterised by the abnormal accumulation of a protein called amyloid in the body’s organs and tissues. There are three main subtypes of amyloidosis (AL), including primary or AL, secondary or AA AL, and hereditary or familial AL. Hereditary AL, which is less common, is caused by an autosomal-dominant mutation, most frequently in the transthyretin (TTR) gene, and has a more favourable prognosis. We report the case of a 51-year-old Vietnamese male who presented with severe dizziness, fainting episodes, low BMI, slow heart rate, and a blood pressure of 60/40 mmHg. The patient had a history of digestive disorders, weakness, and pain in the legs even after disc spine surgery. All symptoms onset occurred at 43 years old. A pathogenic mutation in the TTR gene c.209G>T was confirmed in the patient and 7 out of 15 individuals in his extended family. This is the first case reported in Vietnam diagnosing a new variant of TTR causing typical AL. Based on this study, we conclude that the TTR variant c.209G>T is a pathogenic gene. This study also emphasises the need for increased knowledge regarding AL associated with this pathogenic variant. However, further extensive research is required to provide a comprehensive understanding of the pathogenesis of TTR in the future.