Question

In alkaptonuria (AKU), this is secreted in urine.
(a) Urea
(b) Alanine
(c) Homogentisic acid
(d) Chlorogenic acid

Answer 1

Basically, alkaptonuria is an inherited condition that means it is a feature that presents from birth. We know that inherited conditions are related to genes. So, AKU is caused by a mutation in a gene called homogentisate 1,2-dioxygenase or HGD gene. Characteristically, the excess HGA means sufferers pass dark urine.

Complete Step by Step Answer:
Now we know that alkaptonuria is an autosomal recessive metabolic disorder which is characterized by the accumulation of homogentisic acid, which leads to joint and spine arthritis, and the destruction of the cardiac valves with time. The patients having alkaptonuria also see their urine to turn black when exposed to air. Another characteristic shown in the disorder is ochronosis, a buildup of dark pigment in connective tissues such as cartilage and skin.
So, the correct answer is, ’Homogentisic acid’.

Additional information:

1. People who suffer from alkaptonuria typically develop arthritis, especially in the spine region and in the large joints, at the beginning of early adulthood. Other features of this condition can include heart problems, kidney stones, and prostate stones.
2. Alkaptonuria, also known as homogentisic acid oxidase deficiency, homogentisic aciduria.
3. The HGD gene provides instructions for making an enzyme called homogentisate oxidase which helps in the breakdown of the amino acids namely phenylalanine and tyrosine. They are very important building blocks for the synthesis of proteins. Due to the mutations in the HGD gene, it leads to impair the enzyme's role in the synthesis process. As a result, a substance called homogentisic acid is generated, which is produced from the breakdown of phenylalanine and tyrosine. In this disorder, this HGA started to accumulate in the body.

Note: The transmission of this disease is genetic. There is only a $25\%$ risk of disease transmission to offspring where both parents of the offspring are unaffected carriers. Life expectancy is not significantly reduced but pain can be constant and progressive. Functional decline is observed with a loss of mobility in the patient. They often require the help of any physical aids like crutches, wheelchair. Moreover, Cardiac complications are often life-threatening and may worsen the prognosis.