Cardiac mri detection of a rare case of familial cardiac amyloidosis (Ser23asn): Case report with literature review

Cardiac amyloidosis is a rare disease that has significant sequelae if undetected and treated early. We report a case of a rare genetic mutation that leads to cardiac amyloidosis. This is a case of a 41-year-old Peruvian male without any known past medical history but with a family history of sudden death. The patient complained of episodic left-sided chest pain for 1 month that was associated with shortness of breath. A subsequent admission and workup for coronary artery disease was negative, but an echocardiogram showed global left ventricular hypokinesia. Cardiac magnetic resonance imaging (MRI) was performed which was suggestive of cardiac amyloidosis. A subsequent abdominal fat biopsy and bone marrow biopsy failed to show evidence of amyloidosis. However, the endomyocardial biopsy was consistent with cardiac amyloidosis. Familial cardiac disease was suspected because of the family history of sudden death. As such, genetic testing was performed which yielded a very rare genetic mutation corresponding to amino acid 23 of the transthyretin protein. A review of the literature shows that this gene mutation (AGT23AAT, gene sequence; Ser23Asn, protein sequence) has been described only once previously. This case is unique in that the patient’s amyloidosis was limited to the heart, without involvement of any other organ.