Browse

You are looking at 1 - 2 of 2 items for :

  • Molecular genetic analysis x
  • Hypoglycaemia x
Clear All
Open access

Ved Bhushan Arya, Jennifer Kalitsi, Ann Hickey, Sarah E Flanagan and Ritika R Kapoor

Summary

Diazoxide is the first-line treatment for patients with hyperinsulinaemic hypoglycaemia (HH). Approximately 50% of patients with HH are diazoxide resistant. However, marked diazoxide sensitivity resulting in severe hyperglycaemia is extremely uncommon and not reported previously in the context of HH due to HNF4A mutation. We report a novel observation of exceptional diazoxide sensitivity in a patient with HH due to HNF4A mutation. A female infant presented with severe persistent neonatal hypoglycaemia and was diagnosed with HH. Standard doses of diazoxide (5 mg/kg/day) resulted in marked hyperglycaemia (maximum blood glucose 21.6 mmol/L) necessitating discontinuation of diazoxide. Lower dose of diazoxide (1.5 mg/kg/day) successfully controlled HH in the proband, which was subsequently confirmed to be due to a novel HNF4A mutation. At 3 years of age, the patient maintains age appropriate fasting tolerance on low dose diazoxide (1.8 mg/kg/day) and has normal development. Diagnosis in proband’s mother and maternal aunt, both of whom carried HNF4A mutation and had been diagnosed with presumed type 1 and type 2 diabetes mellitus, respectively, was revised to maturity-onset diabetes of young (MODY). Proband’s 5-year-old maternal cousin, also carrier of HNF4A mutation, had transient neonatal hypoglycaemia. To conclude, patients with HH due to HNF4A mutation may require lower diazoxide than other group of patients with HH. Educating the families about the risk of marked hyperglycaemia with diazoxide is essential. The clinical phenotype of HNF4A mutation can be extremely variable.

Learning points:

  • Awareness of risk of severe hyperglycaemia with diazoxide is important and patients/families should be accordingly educated.

  • Some patients with HH due to HNF4A mutations may require lower than standard doses of diazoxide.

  • The clinical phenotype of HNF4A mutation can be extremely variable.

Open access

Aoife Garrahy, Matilde Bettina Mijares Zamuner and Maria M Byrne

Summary

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.