Alkaptonuria and Skeletal Manifestations

The condition Alkaptonuria results from the deficiency of homogentisic acid oxidase, leading to the buildup of homogentisic acid in the body.

In Alkaptonuria, joint space narrowing in large joints is a common symptom indicating potential degeneration within the appendicular skeleton.

Ochronotic deposition as a result of Alkaptonuria does not affect the cardiovascular system.

Calcification of bursae and tendons is a rare finding in patients with Alkaptonuria affecting the appendicular skeleton.

The symptoms of Alkaptonuria can include glottic narrowing in the upper respiratory tract due to ochronotic deposition.

Alkaptonuria

Alkaptonuria results from the absence of homogentisic acid oxidase.
This leads to a buildup of homogentisic acid, excreted in sweat and urine.
Most cases are inherited in an autosomal recessive pattern (AR).

Axial Skeleton

Osteoporosis is a common finding.
Intervertebral disc calcification, especially in the lumbar spine, occurs.
Disc space narrowing with a "vacuum phenomenon" is observed.
Marginal osteophytes and endplate sclerosis are also present.
Symphysis pubis shows joint space narrowing, chondrocalcinosis, subchondral sclerosis, and rarely ankylosis.

Appendicular Skeleton

Large joints exhibit joint space narrowing, bony sclerosis, articular collapse and fragmentation, and intra-articular loose bodies.
Calcification of bursae and tendons is also seen.

Extraskeletal Manifestations

Ochronotic deposition, a consequence of homogentisic acid buildup, can affect other organs.
Cardiovascular system (CVS): Atherosclerosis, myocardial infarction, and calcification of aortic and mitral valves can occur.
Genitourinary (GU) system: Renal calculi, nephrocalcinosis, and prostatic enlargement with calculi may manifest.
Upper respiratory tract: Glottic narrowing may develop.

This quiz covers the metabolic disorder Alkaptonuria, its genetic inheritance pattern, and includes details on the effects on the axial and appendicular skeleton. It also addresses the extraskeletal manifestations, such as ochronotic deposition, associated with the disease.