Final answer:
Cystine stones in the kidneys are associated with the inherited metabolic disorder cystinuria, which leads to excess accumulation of cystine in urine due to defective amino acid transport and reabsorption.
Step-by-step explanation:
Characteristic Feature of Cystine Kidney Stones
The characteristic feature that distinguishes cystine stones from other types of kidney stones is their unique association with cystinuria, an inherited metabolic disorder. People with cystinuria have a defect in the reabsorption of certain amino acids, leading to an accumulation of cystine in their urine. Over time, this can result in the formation of cystine stones within the kidneys. Unlike other types of kidney stones, which may be influenced by dietary factors like excessive calcium intake or metabolic conditions, cystine stones are directly related to the genetic condition of cystinuria.
Common symptoms for kidney stones include intense 'loin to groin' pain, often described as severe, and hematuria, which is the presence of blood in the urine. These stones are not influenced by the acidity of urine or age of the individual, and are specifically related to defective amino acid transport.