Medical Care
In infancy, a history of dark-stained diapers should alert the physician to alkaptonuria. [8]
Infants, young children, and asymptomatic young adults can be evaluated with simple urine testing on an outpatient basis.
Medical therapy is used to ameliorate the rate of pigment deposition. This minimizes articular and cardiovascular complications in later life.
Reduction of phenylalanine and tyrosine has reportedly reduced homogentisic acid excretion. Whether a mild dietary restriction from early in life would avoid or minimize later complications is not known, but such an approach is reasonable.
Vitamin C, as much as 1 g/d, is recommended for older children and adults. The mild antioxidant nature of ascorbic acid helps to retard the process of conversion of homogentisate to the polymeric material that is deposited in cartilaginous tissues.
Limited use of nitisinone, an inhibitor of the enzyme 4-hydroxyphenylpyruvate dioxygenase, which mediates formation of homogentisic acid, has been reported. Urinary homogentisate excretion was markedly reduced, but safety of prolonged use is still an open question.
Surgical Care
Older individuals may require removal of lumbar discs with fusion.
Hip, shoulder, or knee joint replacement may be necessary.
Consultations
See the list below:
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Biochemical geneticist
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Neurosurgeon
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Orthopedist
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Cardiologist (older patients)
Diet
Reduction of phenylalanine and tyrosine reportedly reduced homogentisic acid excretion in the urine of a child. In an adult, a similar restriction reportedly had no effect on excretion of the abnormal metabolite. Whether a mild dietary restriction from early in life would avoid or minimize later complications is not known, but such an approach is reasonable.
Vitamin C, as much as 1 g/d, is recommended for older children and adults.
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Upon microscopic examination, amber-colored, oval-shaped structures are detected in the mid-to-upper dermal tissues (hematoxylin and eosin, original magnification X40).
