Abstract
Cystinuria is an autosomal recessive disease characterized by impaired transport of cystine and dibasic amino acids in the proximal renal tubule, resulting in the formation of cystine stones. It is believed to account for about 1% of all kidney stones and up to 10% of pediatric stones. Here we report a case of cystinuria with multiple renal stones confirmed by genetic mutational analysis. An 8-month-old girl was admitted to AMC with persistent fever and multiple renal stones. A renal sonogram showed multiple stones at the right renal pelvis, right distal ureter, and left renal medullary portion. An approximately 1 cm renal stone was extracted spontaneously, and stone analysis revealed it to be composed entirely of cystine. Cystinuria was confirmed by increased urine dibasic amino acid levels, including cysteine, and genetic mutational analysis showed the patient to be a homozygote for the pathogenic c. 1820del (p.L607fs) of SLC3A1. Despite treatment with oral hydration and urinary alkalinization, and restricted intake of animal protein, the stones increased in size and number. The patient has since been treated with tiopronin.
8개월 여아가 지속적인 발열 및 다발성 요로 결석으로 입원하여 시행한 신장 초음파에서 오른쪽 신우 및 요관, 왼쪽 수질 부위의 다발성 요로 결석이 보였고, 자연 배출된 1 cm 크기의 결석이 100% 시스틴석으로 확인되었다. 소변 검사에서 시스틴을 비롯한 이염기 아미노산의 상승과 유전자 검사에서 SLC3A1의 c.1820del (p.L607fs)의 동형접합자로 확인되어 시스틴뇨증으로 진단되었다. 충분한 수분 섭취와 소변 알칼리화, 동물성 단백질 제한에도 불구하고 결석의 수와 크기가 증가하여 현재는 tiopronin으로 치료 중이다.