Endocrine Abstracts

Objective

The incidence of maturity-onset diabetes of the young (MODY) in the UK diabetic population is around 1–2% and MODY can also present for the first time in pregnancy. About 70% of cases are caused by mutations in the HNF1α gene. A diagnosis of MODY can affect management following delivery and informs patients. However, untargeted testing is not cost-effective. We wished to see whether screening a sub-group of pregnant women with a high risk of MODY for HNF1α mutations was feasible and could affect outcomes.

Research design and methods

Women attending the diabetic antenatal clinic with any diagnosis of diabetes, who had a family history of diabetes in at least two first-degree relatives, were offered screening for HNF1α mutations. Following delivery, patients were converted to sulphonylurea (SU) or SU+insulin regimes and screening of family members was offered.

Results

In the 12 months from April 2005 to March 2006, 117 pregnancies were booked in the diabetic antenatal clinic. Five women met the criteria and consented to be screened. Three had been diagnosed as T1DM, one as T2DM and one presented with GDM at 16 weeks gestation. Four (80%) were found to be positive for HNF1α mutations, giving an incidence of 4.3%. Following diagnosis of the index cases, further family members were diagnosed with MODY. The glycaemic control of the women with pre-existing diabetes improved following delivery, after adding an SU to their regime, and they also reported improvement in their quality of life.

Conclusions

Screening for MODY in the diabetes antenatal clinic was feasible and likely to be cost-effective. Cases were identified in patients with a prior diagnosis of T1DM, T2DM or GDM, and a strong family history. Following delivery, all responded to SU or an SU+insulin regime with better glycaemic control and improved quality of life.