Metabolic and hereditary factors: Are you stone prone?

Does the adage, “the apple doesn’t fall far from the tree,” apply to kidney stones falling from the kidney? It does, but the reason for this actually has much more to do with environmental than genetic factors. After all, children in families share a home environment with their parents, and they tend to eat and drink the foods and fluids that their parents have available. This is particularly important because dehydration is the most common cause of urinary tract stones. Fluid consumption (or the lack thereof) is the main determinant in stone-forming tendencies. Some innate genetic factors do influence metabolism to make stone formation more likely. These include, in order of decreasing prevalence: excess calcium in the urine (hypercalciuria, 62 %), deficient urinary citrate (hypocitraturia, 41 %), excess urinary urate (hyperuricosuria, 35 %), excess urinary oxalate (hyperoxaluria, 8 %), decreased urinary magnesium (hypomagnesiuria, 1 %), and increased urine levels of the amino acid cystine (cystinuria, 1 %). If it looks like the math doesn’t add up, that is because these conditions can and do coexist in stone-formers. In this chapter, the metabolic conditions and hereditary factors contributing to stone formation are discussed in detail.