An evolving spectrum of diabetes in a woman with GCK-MODY

Coexistence of autoimmune diabetes and maturity-onset diabetes of the young (MODY) is rare. We report the first case of coexisting latent autoimmune diabetes of adulthood (LADA) and glucokinase (GCK) MODY. A 32-year-old woman was treated with insulin for gestational diabetes at age 32 years; post-partum, her fasting blood glucose was 6.0 mmol/L and 2-h glucose was 11.8 mmol/L following an oral glucose tolerance test, and she was maintained on diet alone. Five years later, a diagnosis of LADA was made when she presented with fasting blood glucose of 20.3 mmol/L and HbA1C 125 mmol/mol (13.6%). GCK-MODY was identified 14 years later when genetic testing was prompted by identification of a mutation in her cousin. Despite multiple daily insulin injections her glycaemic control remained above target and her clinical course has been complicated by multiple episodes of hypoglycaemia with unawareness. Although rare, coexistence of latent autoimmune diabetes of adulthood and monogenic diabetes should be considered if there is a strong clinical suspicion, for example, family history. Hypoglycaemic unawareness developed secondary to frequent episodes of hypoglycaemia using standard glycaemic targets for LADA. This case highlights the importance of setting fasting glucose targets within the expected range for GCK-MODY in subjects with coexisting LADA. Learning points: We report the first case of coexisting latent autoimmune diabetes of adulthood (LADA) and GCK-MODY. It has been suggested that mutations in GCK may lead to altered counter-regulation and recognition of hypoglycaemia at higher blood glucose levels than patients without such mutation. However, in our case, hypoglycaemic unawareness developed secondary to frequent episodes of hypoglycaemia using standard glycaemic targets for LADA. This case highlights the importance of setting fasting glucose targets within the expected range for GCK-MODY in subjects with coexisting LADA to avoid hypoglycaemia.

[Intranasal cyanocobalamin; an effective and safe therapeutic alternative]

Vitamin B12 or cobalamin deficiency is a common nutritional disorder, in which the early recognition and treatment is critical since it is a reversible cause of bone marrow failure and demyelinating nervous system disease. Insufficient intake of vitamin along with anatomical or functional disorders of the stomach, pancreas and terminal ileum are the most frequent causes of the deficit. We present three cases of patients with cobalamin deficiency secondary to intestinal malabsorption after bariatric surgery, in relation to autoimmune process and inflammatory bowel disease mechanisms respectively, which conditioned a lack of response to treatment with high-dose oral cyanocobalamin. They also had contraindication to intramuscular administration of cyanocobalamin by the use of oral anticoagulants. In such patients, the use of an inhaled formulation cyanocobalamin provides an adequate absorption, normalizing serum cobalamin and without the existence of side effects.