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Objective: The feasibility of the determination of glutamate purity was studied by differential scanning calorimetry. Methods: Indium and Zinc were used to correct the instrument parameters. Under the conditions of nitrogen atmosphere and flow rate of 50 mL/min, the effects of sample particle size, experimental atmosphere, heating rate and sample quality on the DSC measurement results were investigated, and the glutamic acid purity was determined under the optimal conditions. The determination results were compared between DSC and China Pharmacopeia 2015 titration. Results: Under the condition of weighing 3 mg and heating rate at 40 ℃/min, the purity of glutamic acid was 99.74% and the precision was 0.07%. The purity of glutamic acid measured by titration 99.72%. Conclusion: The DSC method has high accuracy and simple operation, and can be used for the determination of glutamate purity.

Aim: PAX6 is a transcription factor involved in embryonic development of many organs, including the eyes and the pancreas. Mutations of PAX6 gene is the main cause of a rare disease, congenital aniridia (CA). This case–control study aims to investigate the effects of PAX6 mutations on glucose metabolism and insulin secretion in families with CA. Methods: In all, 21 families with CA were screened by Sanger sequencing. Patients with PAX6 mutations and CA (cases) and age‐matched healthy family members (controls) were enrolled. Oral glucose tolerance test (OGTT) was performed to detect diabetes or impaired glucose tolerance (IGT). Insulin and proinsulin secretion were evaluated. Results: Among 21 CA families, heterozygous PAX6 mutations were detected in five families. Among cases (n = 10) from the five families, two were diagnosed with newly identified diabetes and another two were diagnosed with IGT. Among controls (n = 12), two had IGT. The levels of haemoglobin A1c were 36 ± 4 mmol/mol (5.57 ± 0.46%) and 32 ± 5 mmol/L (5.21 ± 0.54%) in the cases and the controls, respectively (p = 0.049). More importantly, levels of proinsulin in the cases were significantly higher than that of the controls, despite similar levels of total insulin. The areas under the curve of proinsulin in the cases (6425 ± 4390) were significantly higher than that of the controls (3709 ± 1769) (p = 0.032). Conclusion: PAX6 may participate in the production of proinsulin to insulin and heterozygous PAX6 mutations may be associated with glucose metabolism in CA patients. [ABSTRACT FROM AUTHOR]