A male newborn was investigated for history of antenatal hyperechogenic colon (HEC) detected at 32 weeks of gestation. In the first week of life, urinary ultrasonography showed nephrolithiasis. Urinary amino acid analysis expressed increased excretion of dibasic amino acids, and high urinary cystine levels were detected in both spot and 24-hour urine specimens. He was diagnosed as cystinuria, and genetic analysis of the patient revealed a heterozygous mutation in SLC7A9 gene. Antenatal presentation of cystinuria with HEC is rare and reported to be associated with a more severe disease course.
Keywords: cystinuria; hyperechogenic colon; nephrolithiasis; prenatal diagnosis.