Inclusion Criteria:

• Male and female English-speaking Caucasian patients >4 years of age with a history of stone formation before age 20 years, their family members, and sex- and age-matched pediatric normal volunteers will be included regardless of current age, gender, race or ethnicity.

Exclusion Criteria:

• Patients will be excluded with voiding dysfunction or metabolic disorders including renal tubular acidosis, chronic renal insufficiency, intestinal malabsorption (inflammatory bowel disease, history of ileal resection or bladder augmentation, and cystic fibrosis), hyperparathyroidism, prolonged immobilization, vitamin D excess, hpercalcemia, hypophosphatasia, Bartter's syndrome, high dose steroid therapy, prematurity, and chronic lasix use. Any child with a bleeding diathesis or who is immunocompromised will be excluded given the increased risks of drawing blood. Participants who have been on anti-seizure medication such as Topamax or other lithogenic drugs and anti-seizure medication will be excluded. Non-English speaking subjects are not eligible to participate in the study, as this study specifically focuses on English-speaking Caucasian patients based on the adult study from which this study project has been derived.