What is the most likely diagnosis for a 17-year-old boy with recurrent renal calculi since the age of 8, and a family history of similar issues?

The most likely diagnosis for a 17-year-old boy with recurrent renal calculi and a family history of similar issues is cystinuria. Cystinuria is an inherited condition characterized by a defect in the renal tubular transport of the amino acid cystine, leading to its accumulation in the urine. The excess cystine can precipitate to form kidney stones, predominantly composed of cystine.

The history of recurrent renal calculi beginning in childhood and the presence of a family history strongly suggest a genetic condition like cystinuria. The autosomal recessive inheritance pattern typically means that cystinuria can run in families, which aligns with the provided family history of similar issues.

In contrast, cystinosis predominantly causes renal tubular Fanconi syndrome, typically presenting with phosphate wasting and aminoaciduria, rather than isolated recurrent stone formation. Familial uric acid nephropathy is usually associated with hyperuricemia and does not explain the specifics of recurrent cystine stones. Primary hyperoxaluria is characterized by calcium oxalate stones and generally presents with more severe systemic issues, including renal failure, rather than simply recurrent stones, particularly in the younger age group.

Thus, cystinuria fits the profile of recurrent stones in a young patient with a