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The tRNA methyltransferase 10 homologue A (TRMT10A) gene encodes tRNA methyl transferase, and biallelic loss of function mutations cause a recessive syndrome of intellectual disability, microcephaly, short stature and diabetes. A case with intellectual disability and distinctive features including microcephaly was admitted. She was diagnosed with epilepsy at 2.5 years old. At 3.6 years of age, severe short stature related to growth hormone (GH) deficiency was detected. She had an incidental diagnosis of diabetes at age 11.4 years which was negative for diabetes antibodies with persistent C-peptide level and she was treated with metformin. Spontaneous puberty did not begin until 15.7 years of age and she was found to have primary ovarian failure. A homozygous p.Arg127* mutation in TRMT10A was detected. In addition to the typical clinical features which characterize TRMT10A syndrome, we observed an unusual form of impaired glucose metabolism which presented in early childhood with hypoglycemia followed by diabetes in late childhood. GH deficiency and primary ovarian failure may also be additional findings of this syndrome. Patients with slow onset diabetes who are negative for autoantibodies and have extra-pancreatic features should be tested for all known subtypes of monogenic diabetes.

Objective:Monogenic diabetes is a heterogeneous disease that causes functional problems in pancreatic beta cells and hyperglycemia. The aim of this study was to determine the clinical and laboratory features, the admission characteristics and distribution of monogenic form of diabetes in childhood in Turkey.Methods:Patients aged 0-18 years, who were molecularly diagnosed with monogenic diabetes, and consented to participate, were included in the study.Results:Seventy-seven (45.6%) female and 92 male cases with a mean age of 8.18±5.05 years at diagnosis were included. 52.7% of the cases were diagnosed with monogenic diabetes by random blood glucose measurement. The reason for genetic analysis in 95 (56.2%) of cases was having a family member diagnosed with diabetes under the age of 25. At the time of diagnosis, ketone was detected in urine in 16.6% of the cases. Mean hemoglobin A1c on admission, fasting blood glucose, fasting insulin, and c-peptide values were 7.3±2.1%, 184.9±128.9 mg/dL, 9.4±22.9 IU/L, 1.36±1.1 and ng/L respectively. GCK-MODY was found in 100 (59.2%), HNF1A-MODY in 31 (18.3%), and variants in ABCC8 in 6 (3.6%), KCNJ11 in 5 (3%), HNF4A in 2 (1.2%), and HNF1B in 2 (1.2%).Conclusion:Recent studies have indicated HNF1A-MODY is the most frequent of all the MODY-monogenic diabetes cases in the literature (50%), while GCK-MODY is the second most frequent (32%). In contrast to these reports, in our study, the most common form was GCKMODY while less than 20% of cases were diagnosed with HNF1A-MODY.