Introduction -- Alkaptonuria and Ochronosis -- History -- Metabolism of Aromatic Amino Acids -- Tyrosine Metabolism Disorders -- Detection of Homogentisic Acid in Plasma and Urine -- Alkaptonuria Genetics -- Experimental Alkaptonuria in Animals -- Experimental Models of Alkaptonuria and Ochronosis -- Ochronotic Arthropathy -- Clinical Manifestation of Ochronotic Arthropathy in the Spine -- Analysis of X-Ray Symptomatology of Ochronotic Arthropathy in the Spine -- Clinical Manifestation of Ochronotic Arthropathy in the Peripheral Joints -- Clinical and Ultrasound Evaluation of Enthesopathy in Alkaptonuria in the Romani Community -- Analysis of X-Ray Symptomatology of Ochronotic Arthropathy in the Area of the Peripheral Joints -- Manifestations of Alkaptonuric Ochronosis in the Eye -- Symptoms of Alkaptonuria and Ochronosis in the Ear -- Manifestations of Alkaptonuria and Ochronosis in the Visceral Organs -- Manifestations of Alkaptonuria and Ochronosis in the Respiratory Tract -- Pathological Anatomy and Histology of Ochronosis -- Cellular and Molecular Patholgenesis of Ochronosis -- Picture of Synovial Effusion in Ochronosis -- Coincidence of Alkaptonuric Ochronosis with Other Diseases -- Differential Diagnosis of the Disease -- Sine Syndromes in Alkaptonuria -- History of Nitisinone (NTBC) -- Case Reports -- References.