Endocrine Abstracts

Background: I present a young girl with maturity onset diabetes of young type 5 (MODY 5) who presented with renal cysts and early onset bilateral cataracts with gradual decline of beta cell functions.

Case: 19 years old girl presented to A&E with hyperglycemia, ketosis, and acidosis. This was her second presentation in A&E in previous 3 weeks. She was diagnosed with type 1 diabetes when she was 3 years old in view of her polyuria and slow growth. She had normal vaginal delivery without any complications. Her maternal grandmother had type 2 diabetes and no other family member was known to have diabetes. Her glycemic control had always been poor with HbA1c ranging between 10 and 15% (85–140 mmol/mol). She never developed diabetic ketoacidosis prior to these two episodes. She had been treated with twice daily pre-mixed insulin (30% short acting/70% intermediate acting insulin). She was supposed to be taking 34 units in the morning and 38 units in the evening. She had also received metformin in view of her large doses of insulin to improve insulin sensitivity. In past medical history she had her bilateral cataract surgery done at age 14 years. She was found to have urine ACR of 29 mg/mmol on this admission and C-peptide levels were 0.62 ng/ml (0.71–2.72 ng/ml). Her USS of kidneys showed multiple cysts. In view of her atypical presentation for type 1 diabetes and renal cysts she had her genetic analysis done which showed HNF1b mutation (heterozygous) consistent with MODY 5. She did not develop DKA earlier as MODY 5 patients do have some β cell function which gradually decline and hence she started developing DKA now when her β cell function had reduced significantly. Renal cysts are also a well-known feature of MODY5 however none of the previously reported cases in literature have mentioned early onset bilateral cataracts in such patients. Since the MODY5 is rather rare and the clinical manifestations are variable, early onset cataract could be an even less common manifestation of the disease.

Conclusion: Careful history is important in diagnosing patients with MODY and differentiating them from type 1 diabetes. Early onset cataract has not been described in previously reported cases of MODY5.