<prompt> Features of cystinuria areImpaired proximal tubular reabsorption of cystinAutosomal recessiveRecurrent renal stoneAll of above  <response>: Cystinuria is an autosomal recessive disorder characterized by impaired tubular reabsorption of cystine and dibasic amino acids ornitine,lysine and arginine Thus occurs supersaturation of urine with cystine crystals leading to formation of radiopaque calculi . Reference : Ghai TB of pediatrics 8th edition pg 503. 