Koulivand Leila, Mohammadi Mehrdad, Ezatpour Behrouz, Kheirollahi Majid
Pediatrics Inherited Diseases Research Center and Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
Iran J Kidney Dis. 2015 Jan;9(1):63-6.
Cystinuria, one of the first inborn errors of metabolism, is characterized by hyperexcretion of cystine, arginine, lysine, and ornithine into urine. Cystinuria is genetically classified into types A and B. Mutations in the SLC3A1 gene lead to type A, and type B is caused by mutations in the SLC7A9 gene. We described a 19-year-old woman that had early onset of cystine calculus formation at the age of 3 years. After DNA extraction and polymerase chain reaction, direct sequencing was performed. By these methods, a novel nucleotide substitution c.177G>A in exon 3 of the SLC7A9 gene was found, which had not been reported elsewhere previously. This nucleotide substitution occurs in the extracellular domain of the SLC7A9 gene. In addition, a previously described intron variant c.1136+2/3delT (intron 6 of SLC3A1) in homozygosity status was detected in the patient. To our knowledge, this is the first report of novel nucleotide substitution c.177G>A in exon 3 of the SLC7A9 gene.
胱氨酸尿症是最早发现的先天性代谢缺陷疾病之一，其特征是尿液中胱氨酸、精氨酸、赖氨酸和鸟氨酸排泄过多。胱氨酸尿症在遗传学上分为A、B两型。SLC3A1基因突变导致A型，而B型是由SLC7A9基因突变引起的。我们报道了一名19岁女性，她在3岁时就过早出现了胱氨酸结石。在提取DNA并进行聚合酶链反应后，进行了直接测序。通过这些方法，在SLC7A9基因外显子3中发现了一个新的核苷酸替换c.177G>A，此前在其他地方尚未见报道。这种核苷酸替换发生在SLC7A9基因的细胞外结构域。此外，在该患者中检测到了纯合状态的先前描述的内含子变异c.1136+2/3delT（SLC3A1基因的内含子6）。据我们所知，这是首次报道SLC7A9基因外显子3中出现新的核苷酸替换c.177G>A。
