Cystine storage disease

Introduction A hereditary defect in the renal tubules is caused by a decrease in renal tubular reabsorption of cystine and an increase in urinary content, and cystine formation is often formed in the urinary tract. Cystatineuria is autosomal recessive, and the secretion of cystine in the urine of heterozygotes can also be increased, but few stones are formed. The reabsorption of the two base amino acids (lysine, arginine, ornithine) is also affected, but does not cause symptoms, because they have a transport system in addition to a transport channel shared with cystine. They are also more soluble in urine than cystine, so as not to cause crystallization and stone formation. Their absorption in the small intestine (including cystine) is also reduced.

Cause

The main problem with cystineuria is the reduction of cysteine reabsorption in the renal tubules, which leads to an increase in the concentration of cystine in the urine. Cystine is less soluble in acidic urine and precipitates when its concentration exceeds its solubility, forming crystals or stones.

The reabsorption of the two base amino acids (lysine, arginine, ornithine) is also affected, but does not cause symptoms, because they have a transport system in addition to a transport channel shared with cystine. They are also more soluble in urine than cystine, so as not to cause crystallization and stone formation. Their absorption in the small intestine (including cystine) is also reduced.

an examination

Related inspection

Urine routine nephropathy

Renal amino aciduria is a group of hereditary membrane transport-deficient diseases in which a large number of amino acids are excreted from the urine due to a barrier to amino acid reabsorption in the proximal tubules.

Diagnostic criteria:

1. History of family hereditary diseases.

2, there are symptoms and signs of kidney stones, such as colic, hematuria, urinary tract obstruction and / or urinary tract infection.

3, urinary tract repeated cystine stones, urinary sediment microscopic examination visible hexagonal flat crystal.

4, KUB X-ray film can be seen in bilateral urinary tract with multiple hair, thin shadows, varying sizes of stones.

5, urine nitrohydrocyanate test positive can determine the diagnosis.

Differential diagnosis

The most common symptom of cystineuria is renal colic, which usually occurs between the ages of 10 and 30. Urinary tract obstruction can cause urinary sensation and renal failure.

An opaque cystine stone occurs in the renal pelvis or bladder. Common staghorn calculus, cystine forms a yellow-brown, hexagonal crystal in the urine. Excess cystine in the urine can be detected by the nitroprusside cyanide test. Chromatography and electrophoresis can further confirm the diagnosis.

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