Yılmaz Agladioglu Sebahat, Sagsak Elif, Aycan Zehra
Pediatric Endocrinology Clinic, Dr. Sami Ulus Children's Health and Disease Training and Research Hospital, Ankara, Turkey.
Horm Res Paediatr. 2015;84(1):54-61. doi: 10.1159/000375410. Epub 2015 Mar 17.
The urinary C-peptide/creatinine ratio (UCPCR) and fasting C-peptide level can assess beta-cell function in clinical practice. In the present study, the use of the UCPCR and fasting C-peptide levels was investigated in the differential diagnosis between maturity-onset diabetes of the young (MODY) and type 1 diabetes mellitus (T1DM).
Twenty-seven patients with genetically confirmed MODY by next-generation sequence analysis and 42 children with T1DM were included. C-peptide levels were measured after an overnight fast before breakfast, and urine samples were collected 2 h after a standard lunch in the hospital.
The UCPCR in the T1DM group was 0.17 ± 0.5 nmol/mmol, and in the MODY group it was 1.27 ± 1.03 nmol/mmol (p = 0.001). The receiver operating characteristic (ROC) curves showed excellent discrimination (area under the curve 0.93). A UCPCR ≥0.22 nmol/mmol yielded a 96.3% sensitivity and an 85.7% specificity. The fasting C-peptide level in the T1DM group was lower than that in the MODY group (p = 0.001). The fasting C-peptide cutoff determined by ROC curve analysis was 0.62 ng/ml, with a sensitivity of 93% and a specificity of 90% for discriminating between MODY and T1DM.
We showed that the UCPCR and fasting C-peptide levels in children and adolescents can distinguish patients with MODY from patients with T1DM with high specificity and sensitivity. A value of UCPCR ≥0.22 nmol/mmol may indicate further genetic testing for MODY.
尿C肽/肌酐比值（UCPCR）和空腹C肽水平可在临床实践中评估β细胞功能。在本研究中，对UCPCR和空腹C肽水平在青年发病的成年型糖尿病（MODY）与1型糖尿病（T1DM）的鉴别诊断中的应用进行了研究。
纳入27例经下一代测序分析基因确诊的MODY患者和42例T1DM儿童。早餐前空腹过夜后测量C肽水平，并在医院标准午餐后2小时收集尿液样本。
T1DM组的UCPCR为0.17±0.5 nmol/mmol，MODY组为1.27±1.03 nmol/mmol（p = 0.001）。受试者工作特征（ROC）曲线显示出良好的区分度（曲线下面积为0.93）。UCPCR≥0.22 nmol/mmol时，敏感性为96.3%，特异性为85.7%。T1DM组的空腹C肽水平低于MODY组（p = 0.001）。通过ROC曲线分析确定的空腹C肽临界值为0.62 ng/ml，用于区分MODY和T1DM时，敏感性为93%，特异性为90%。
我们表明，儿童和青少年的UCPCR和空腹C肽水平能够以高特异性和敏感性区分MODY患者与T1DM患者。UCPCR≥0.22 nmol/mmol的值可能提示进一步进行MODY的基因检测。
