Black Aorta from Alkaptonuria

Area of Science:

• Cardiovascular Medicine
• Genetics
• Metabolic Disorders

Background:

• Alkaptonuria is a rare autosomal recessive metabolic disorder caused by deficiency of the enzyme homogentisate 1,2-dioxygenase.
• This deficiency leads to the accumulation of homogentisic acid (HGA), resulting in ochronosis, a condition characterized by deposition of pigment in connective tissues.
• Ochronosis can affect various tissues, including cartilage, skin, and the cardiovascular system, potentially leading to valvular and aortic complications.

Purpose of the Study:

• To report a case of symptomatic aortic stenosis in a patient with a history of alkaptonuria and ochronosis.
• To describe the intraoperative findings of a severely pigmented and porcelain aorta in this patient.
• To underscore the potential cardiovascular manifestations of ochronosis.

Main Methods:

• Case report of a 76-year-old male patient.
• Review of patient's past medical history including diagnosis of alkaptonuria.
• Surgical aortic valve replacement procedure.
• Intraoperative gross examination of the aorta.

Main Results:

• The patient presented with symptomatic aortic stenosis.
• During aortic valve replacement, the aorta was observed to be severely pigmented and had a porcelain-like consistency.
• These findings are consistent with advanced ochronosis affecting the aorta.

Conclusions:

• Alkaptonuria with ochronosis can lead to significant cardiovascular complications, including severe aortic stenosis and aortic wall pathology.
• The "porcelain aorta" finding in this case highlights the extensive tissue deposition and calcification associated with long-standing HGA accumulation.
• This case emphasizes the importance of recognizing and monitoring for cardiovascular involvement in patients with alkaptonuria.