Abstract：
BACKGROUND: Hyperglycinuria is a rare disorder, with few reported cases, caused by either a defect in glycine metabolism or a disturbance in renal glycine reabsorption. Genetic findings of hyperglycinuria are rare and have not previously been reported in Chinese young men.
METHODS: A 24-year-old man presented with a compliant of bilateral lumbago for 1 month. Abdominal computed tomography revealed bilateral kidney stones and right upper ureteral dilatation. The 24-h urine analysis showed high urine oxalate levels of 63 mg/day. Analysis of amino acids in urine revealed that his urinary glycine levels were abnormally high (2.38 µmol/mg creatinine). Whole-exome sequencing detected the SLC6A19 variant c.1278 C > T p. (Cys426). Flexible ureteroscopy with holmium laser lithotripsy was conducted twice to remove his bilateral nephrolithiasis. Postoperative stone biochemical composition analysis revealed that the stones were composed of approximately 70% calcium oxalate monohydrate and 30% calcium oxalate dihydrate. The patient was subsequently diagnosed with hyperglycinuria. Three months after the stone surgery, ultrasonography revealed one nodule under the right thyroid lobe during a health checkup. His serum parathyroid hormone (PTH) levels increased to 392.3 pg/mL. Resection of the right parathyroid nodule was performed, and the histopathological examination confirmed right parathyroid adenoma. During the 2-year follow-up period, nephrolithiasis did not relapse, and serum PTH, calcium, and phosphorus levels were normal.
CONCLUSIONS: The SLC6A19 gene may have been significant in the development of hyperglycinuria in a Chinese young man. Further evaluation for the possibility of a glycine excretion disorder could be considered when encountering nephrolithiasis.
METHODS: A 24-year-old man presented with a compliant of bilateral lumbago for 1 month. Abdominal computed tomography revealed bilateral kidney stones and right upper ureteral dilatation. The 24-h urine analysis showed high urine oxalate levels of 63 mg/day. Analysis of amino acids in urine revealed that his urinary glycine levels were abnormally high (2.38 µmol/mg creatinine). Whole-exome sequencing detected the SLC6A19 variant c.1278 C > T p. (Cys426). Flexible ureteroscopy with holmium laser lithotripsy was conducted twice to remove his bilateral nephrolithiasis. Postoperative stone biochemical composition analysis revealed that the stones were composed of approximately 70% calcium oxalate monohydrate and 30% calcium oxalate dihydrate. The patient was subsequently diagnosed with hyperglycinuria. Three months after the stone surgery, ultrasonography revealed one nodule under the right thyroid lobe during a health checkup. His serum parathyroid hormone (PTH) levels increased to 392.3 pg/mL. Resection of the right parathyroid nodule was performed, and the histopathological examination confirmed right parathyroid adenoma. During the 2-year follow-up period, nephrolithiasis did not relapse, and serum PTH, calcium, and phosphorus levels were normal.
CONCLUSIONS: The SLC6A19 gene may have been significant in the development of hyperglycinuria in a Chinese young man. Further evaluation for the possibility of a glycine excretion disorder could be considered when encountering nephrolithiasis.
摘要：
背景：高血糖是一种罕见的疾病，报告的病例很少，由甘氨酸代谢缺陷或肾脏甘氨酸重吸收障碍引起。高血糖症的遗传发现很少见，以前在中国年轻男性中没有报道。
方法：一名24岁男子表现为符合双侧腰痛1个月。腹部计算机断层扫描显示双侧肾结石和右上输尿管扩张。24小时尿液分析显示，尿液草酸盐水平很高，为63mg/天。尿液中的氨基酸分析表明，他的尿甘氨酸水平异常高（2.38µmol/mg肌酐）。全外显子组测序检测到SLC6A19变体c.1278C>Tp.(Cys426)。输尿管软镜钬激光碎石术两次切除双侧肾结石。术后结石生化成分分析表明，结石由大约70％的草酸钙一水合物和30％的草酸钙二水合物组成。患者随后被诊断患有高血糖尿。结石手术三个月后,在健康检查中，超声检查显示右甲状腺叶下有一个结节。他的血清甲状旁腺激素（PTH）水平增加到392.3pg/mL。切除右侧甲状旁腺结节，组织病理学检查证实右侧甲状旁腺腺瘤。在2年的随访期间，肾结石没有复发,和血清PTH,钙，磷水平正常.
结论：SLC6A19基因可能在中国年轻人高血糖症的发展中具有重要意义。遇到肾结石时，可以考虑进一步评估甘氨酸排泄障碍的可能性。
方法：一名24岁男子表现为符合双侧腰痛1个月。腹部计算机断层扫描显示双侧肾结石和右上输尿管扩张。24小时尿液分析显示，尿液草酸盐水平很高，为63mg/天。尿液中的氨基酸分析表明，他的尿甘氨酸水平异常高（2.38µmol/mg肌酐）。全外显子组测序检测到SLC6A19变体c.1278C>Tp.(Cys426)。输尿管软镜钬激光碎石术两次切除双侧肾结石。术后结石生化成分分析表明，结石由大约70％的草酸钙一水合物和30％的草酸钙二水合物组成。患者随后被诊断患有高血糖尿。结石手术三个月后,在健康检查中，超声检查显示右甲状腺叶下有一个结节。他的血清甲状旁腺激素（PTH）水平增加到392.3pg/mL。切除右侧甲状旁腺结节，组织病理学检查证实右侧甲状旁腺腺瘤。在2年的随访期间，肾结石没有复发,和血清PTH,钙，磷水平正常.
结论：SLC6A19基因可能在中国年轻人高血糖症的发展中具有重要意义。遇到肾结石时，可以考虑进一步评估甘氨酸排泄障碍的可能性。
