ESPE Abstracts

Objective: To report a family with MODY2 associated with GCK gene mutation and improve clinicians' understanding of this gene mutation.

Methods: The clinical manifestations, laboratory examinations and genetic test results of a MODY2 family diagnosed and treated in our hospital were analyzed retrospectively, and the related literatures were reviewed.

Results: The patient is a 6-year-old girl, her family members measured the fasting fingertip blood glucose of the child due to abnormal blood glucose of her sister. Moreover, the postprandial blood glucose fluctuated between 6.2 and 9.2mmol/L. Her HbA1c was 6.2% and fasting venous blood glucose was 8.0 mmol/L. She usually drink more and urinate more, and urinate twice a night, without polyphagia, polydipsia, thirst or weight loss. Her sister was 3 years and 5 months old and had a history of similar abnormal blood glucose. Her mother have a history of gestational diabetes, but poor diet control, whose fasting blood glucose fluctuated between 6 and 8mol/l, and had been given insulin therapy during that time. Now she had oral administration of metformin. The patient’s grandmother was diagnosed with type 2 diabetes at the age of 52, with a maximum fasting blood glucose of about 10 mmol/L. On physical examination, she weighed 20 kg, was 116 cm tall, and had a BMI of 14.86 kg/m2, no positive signs. Auxiliary examination: shows that fasting venous blood glucose was 6.1 mmol/l, fasting C-peptide was 174 pmol/l, 2-hour postprandial blood glucose was 8.9 mmol/l, insulin autoantibodies were negative. There was no abnormality in her liver and kidney function, electrolytes, thyroid function and cortisol. The whole exome sequencing presented GCK gene (hg19) chr7:44192993: NM000162.5: c.112114dup: p.Gln38dup (heterozygous mutation), inherited from the mother, the pathogenic grade was unknown mutation. Her sister carried the same gene and the same mutation site.

Conclusion: MODY is a monogenic diabetes characterized by impaired insulin secretion and 14 different genetic variants have been reported. The GCK gene is located on chromosome 7, and heterozygous variants can cause MODY2. MODY 2 is the most common cause of asymptomatic familial hyperglycemia. The insulin secretion function of patients is normal, and the threshold of regulating blood glucose is high. Conventional doses of insulin or oral hypoglycemic drugs can not effectively control patients’ blood glucose. Most patients’ blood glucose can been controlled through simple diet and exercise, and there are few long-term microvascular or macrovascular complications.