A 9-year-old girl presents with poor growth, muscle weakness…
A 9-year-old girl presents with poor growth, muscle weakness, and polyuria. Her mother reports she has been “always thirsty” and has had intermittent vomiting for several months. Vitals are normal. Physical exam shows mild dehydration and short stature. Lab results: Na: 138 mEq/L K: 2.9 mEq/L Cl: 112 mEq/L HCO3: 15 mEq/L Ca: 8.8 mEq/L Anion gap: normal Creatinine: normal Urine pH: 6.5 No urine glucose or protein Renal Ultrasound: normal kidneys, no nephrocalcinosis Which diagnosis best explains this patient’s presentation?