Alkaptonuria is caused by a deficiency of which enzyme?
A
Phenylalanine hydroxylase
Analysis & Theory
Alkaptonuria results from a deficiency of homogentisate oxidase, an enzyme in the tyrosine degradation pathway.
Which of the following is a clinical feature of alkaptonuria?
C
Black urine on standing
Analysis & Theory
In alkaptonuria, homogentisic acid accumulates and oxidizes, turning urine dark on standing.
Alkaptonuria follows which pattern of inheritance?
Analysis & Theory
Alkaptonuria is inherited in an autosomal recessive manner.
Which metabolic pathway is affected in alkaptonuria?
A
Phenylalanine and tyrosine degradation
Analysis & Theory
The degradation of phenylalanine and tyrosine is disrupted due to homogentisate oxidase deficiency.
A key complication of alkaptonuria in adults is:
Analysis & Theory
Deposition of pigment in connective tissues leads to ochronosis and joint problems.
Albinism is primarily caused by a defect in the production of:
Analysis & Theory
Albinism is caused by defects in melanin production, leading to hypopigmentation.
The enzyme deficient in oculocutaneous albinism is often:
B
Phenylalanine hydroxylase
Analysis & Theory
Tyrosinase is essential for melanin synthesis from tyrosine; its deficiency leads to albinism.
Albinism is commonly associated with which of the following vision issues?
Analysis & Theory
Nystagmus (involuntary eye movement) is a common feature in individuals with albinism.
Albinism is inherited in which of the following ways?
Analysis & Theory
Most types of albinism are inherited in an autosomal recessive pattern.
People with albinism are more sensitive to sunlight due to:
B
Lack of melanin in the skin
Analysis & Theory
Melanin protects the skin from UV rays; its absence increases sun sensitivity.