Endocrine Abstracts

Maturity-onset diabetes of young 5 (MODY5) is a type of monogenic diabetes involving multiple organs including pancreas and kidneys. This is caused by mutation/deletion of the hepatocyte nuclear factor-1β (HNF-1β) gene located in the chromosome region 17q12.

We report a 10-year-old, non-obese girl who was diagnosed with diabetes with features of insulin resistance. She was found to have a heterozygous whole gene deletion of HNF-1β and was diagnosed with MODY5. She was antenatally diagnosed with gallbladder duplication cyst, which could now be explained by the same genetic defect, as HNF-1β is expressed in the liver and biliary system and conditional HNF-1β knockout mouse showed similar features. She also had developmental delay, learning difficulties and autistic spectrum disorder. Interestingly these features could be explained by the contiguous gene deletion in the long arm of chromosome 17 within band q12 which included the HNF-1β gene found by further Microarray analysis. Following her genetic diagnosis, she was screened for other known associated features and was noted to have renal cyst and bicornuate uterus. She was treated with Metformin initially but soon she needed insulin treatment to maintain normoglycaemia.

We report this first case of MODY5 with gallbladder duplication cyst and to our knowledge this association has not been reported in the literature so far. This case highlights the importance of genetic testing which was very useful in finding an explanation for all of the problems and to plan the management appropriately. Although the biochemical features and the initial management might be similar to patients with type 2 diabetes, it is very important to understand the need for insulin treatment earlier in the course of the disease and to screen for other associated problems.