Endocrine Abstracts

Monogenic diabetes is estimated to account for as much as 4% of childhood and adolescent diabetes. Positive test rates for monogenic diabetes in the UK have been reported as 23%¹. The aim of this study was to determine positive testing rates among adults within the University of Limerick Hospital Group catchment population of approximately 413,000 people. Adults (age >16years) who underwent screening for monogenic diabetes over a 24 month (January 2021 to December 2022) were identified from biochemistry laboratory records and included in the study. Hospital records were used to acquire clinical and biochemical data. Twenty-two adults underwent screening for monogenic diabetes during the study period. The mean±SD age at the time of screening was 47.3±18.1 years. 86.4% of this group underwent proband screening with the remainder having a relative with a known monogenic diabetes diagnosis. Nine adults (41%) tested positive for monogenic diabetes, seven for pathogenic GCK mutations and two for mitochondrial diabetes. There was no significant difference in mean±SD age of those testing positive (45.4±19.9years) vs testing negative (48.5±18.3years), P = 0.35. The positive testing rate among probands and relatives was 36.8% and 66.7% respectively. Islet antigen antibody testing and c-peptide measurement are considered a pre-requisite to genetic testing. However, n = 3(13%) had no previous antibody testing and c-peptide levels were not measured for n = 8(35%). When measured, c-peptide was detectable in all. A MODY probability score was not recorded for any patient yet was only applicable in n = 4 due to age>35 or missing biochemical data. To conclude monogenic diabetes testing rates among adult probands is 2.3/100,000 per year in the Midwest of Ireland. Rates of monogenic diabetes detection among adults within this region exceed the average reported across the UK¹.

Reference1. Pang, L. et al. (2022). Diabetes Care, 45(3), pp. 642–649. doi:10.2337/dc21-2056.