Final answer:
Alkaptonuria is an autosomal recessive genetic disorder where affected individuals cannot properly metabolize the amino acids phenylalanine and tyrosine. Patients who inherit the disease produce a defective enzyme involved in metabolizing these amino acids.
Step-by-step explanation:
Alkaptonuria is an autosomal recessive genetic disorder where affected individuals cannot properly metabolize the amino acids phenylalanine and tyrosine. As a result, they may experience symptoms such as darkened skin, brown urine, and joint damage. Archibald Garrod reasoned that patients who inherited the disease produced a defective enzyme involved in metabolizing these amino acids.