Homozygous deletion of TRMT10A as part of a contiguous gene deletion in a syndrome of failure to thrive, delayed puberty, intellectual disability and diabetes mellitus

Two recent reports describe a new syndrome of intellectual disability, short stature, microcephaly, and young onset diabetes or disturbed glucose metabolism in association with inactivating mutations in the TRMT10A gene. We investigated the clinical spectrum presented by a 17-year-old female with a homozygous contiguous gene deletion involving the TRMT10A gene. From infancy, she presented with failure to thrive and microcephaly. Puberty was characterized by a slow and an inconsistent course of progression. Concomitantly, gonadotropin levels fluctuated between low and high levels which were compatible with gonadal failure. Unlike the previous reports, the patient had ketoacidosis at onset of diabetes and islet cell autoantibodies. Nevertheless, glycemic control was excellent (HbA1C 5.0%-6.2%). RT-PCR and Western blot analysis demonstrated a complete abolishment of TRMT10A mRNA and its translated protein. In order to elucidate the nature of diabetes in this patient, endogenous insulin secretion and glycemic control were evaluated by a glucagon stimulation test and continuous glucose monitoring both during insulin treatment and off therapy. Endogenous insulin secretion still persisted 22 months after onset of diabetes and relatively normal glucose levels were kept over 3 days without insulin treatment. The fluctuating course of puberty and diabetes may reflect intermittent apoptotic damages due to sensitization of the relevant cells to various stress agents in the absence of functional TRMT10A.