A genetic diagnosis of HNF1A diabetes alters treatment and improves glycaemic control in the majority of insulin-treated patients.
OBJECTIVE
Hepatocyte nuclear factor-1 alpha (HNF1A) gene mutations are the commonest cause of monogenic diabetes, but patients are often misdiagnosed as having Type 1 diabetes and started on insulin treatment. Patients with HNF1A diabetes are particularly sensitive to the glucose-lowering effect of sulphonylureas, which are the pharmacological treatment of choice. We aimed to assess if patients do change from insulin to sulphonylurea treatment when HNF1A diabetes is confirmed and the impact of this treatment change on long-term glycaemic control.


METHODS
We investigated the clinical course of 43 patients who were insulin treated from diagnosis for a median 4 years (range 1-14) before an HNF1A gene mutation was identified.


RESULTS
Thirty-four patients (79%) stopped insulin following genetic testing and transferred to sulphonylureas. Twenty-four of them (71%) remained off insulin at a median 39 months (range 17-90) post-transfer. The 10 patients who recommenced insulin had a trend towards a longer duration of diabetes (18 vs. 7 years, P = 0.066) compared with those remaining on tablets. The median glycated haemoglobin (HbA(1c)) was good (6.9%; interquartile range 6.3-8.0%) in the patients who remained off insulin and 19/24 patients (79%) achieved HbA(1c) < 7.5% or improved their pre-genetic diagnosis HbA(1c) by > 1.0%. Transfer off insulin was not attempted in eight patients: one of these was planning pregnancy and two chose to remain on insulin.


CONCLUSIONS
In this observational study we found that a molecular genetic diagnosis of HNF1A diabetes does alter treatment in clinical practice, with 79% attempting transfer to sulphonylureas. Transfer to sulphonylureas was successful in the majority of patients without deterioration in glycaemic control.
Shepherd
M
M
Institute of Health and Social Care Research Peninsula Medical School, Exeter, UK. m.h.shepherd@exeter.ac.uk
Shields
B
B
Ellard
S
S
Rubio-Cabezas
O
O
Hattersley
A T
AT
D001786:Blood Glucose / Q000235:genetics; D003920:Diabetes Mellitus / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D051538:Hepatocyte Nuclear Factor 1-alpha / Q000235:genetics*; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D007328:Insulin / Q000627:therapeutic use; D008297:Male; D009154:Mutation / Q000235:genetics; D017410:Practice Guidelines as Topic; D013453:Sulfonylurea Compounds / Q000627:therapeutic use
D001786:Blood Glucose; D051538:Hepatocyte Nuclear Factor 1-alpha; D007004:Hypoglycemic Agents; D007328:Insulin; D013453:Sulfonylurea Compounds