Can prenatal renal pelvicalyceal echogenic foci support the diagnosis of cystinuria?

Cystinuria is an inherited disease caused by a defect in renal and intestinal tubular transport affecting cystine and dibasic amino acids (lysine, ornithine and arginine). It is transmitted as an autosomal recessive disease. On fetal ultrasound, the colon is usually seen as hypoechoic or isoechoic. Antenatal hyperechoic appearance of the fetal colon was previously considered as a normal variant. However, recent studies have shown that hyperechoic colon is associated with cystinuria. We present a case of cystinuria, who was referred to us due to fetal hyperechogenic colon at 32 weeks of gestation. Additional fetal pericalyceal echogenic focal structures were observed on ultrasonography. The diagnosis of cystinuria was confirmed in the postnatal period.