Back
Maturity onset diabetes of the young type 5 (MODY 5) or Diabetes and Renal Cysts Syndrome, a rare genetic kidney disease, is very easy to misdiagnose as type 2 diabetes or other genetic electrolytes disorders like Gitelman or Bartters syndrome. To get a better understanding of the disease. I report a case of a patient who was initially misdiagnosed as having Gitelman’s syndrome due to severe hypomagnesemia and hypokalemia. And a review of the actual literature to analyze the clinical characteristics and gene mutations of MODY5. “MODY5” OR “HNF1B maturity–onset diabetes of the young" OR “maturity-onset diabetes of the young type 5" OR “renal cysts and diabetes syndrome”.
Case Presentation: I reported a case of MODY 5 or Diabetes and Renal Cysts Syndrome, which presented with severe hypomagnesemia, hypokalemia, renal cysts in her renal ultrasound, and normal kidney function. The patient was initially misdiagnosed with Gitelman syndrome due to her severe hypomagnesemia and hypokalemia. She was tested with Renasight (Natera) and a diagnosis of Diabetes and Renal Cysts Syndrome was done with a report of HNF1B whole gene deletion.
A 19 yo Caucasian woman with h/o Gitelman Syndrome who was originally followed up by her pediatrician and nephrologist in California and now came to my office to establish care as an adult patient. She has multiple comorbidities and issues related to her presumptive Gitelman's diagnosis (hypomagnesemia, hypokalemia). She has normal kidney function but has cysts in her kidneys. Her PMH is significant for IBS, HTN/hypotension, and malabsorption due to chronic diarrhea, and she has h/o chronic pain, postural orthostatic tachycardia syndrome (POTS), and Vit B6 deficiency. ROS: she has nausea and vomiting and is taking symptomatic treatment with Marinol, Promethazine, and Zofran. She has a history of headaches and feeling weak at times, no weight loss, and uses daily TPN and infusions of Potassium Chloride (KCL) and Magnesium sulfate. She has low BP at times and uses compression stockings.
Tests:
Hb/Hcto: 12.5, WBC: 7,600, Plat: 29,000. Creatinine was 0.8 mg/dL, eGFR 115 mL/min, and Cystatin C: 1.1 mg/dL. Magnesium levels from1.4 to 1.8 mg/dL Mag: 0.7---> 1.6 mg/dL, Potassium levels 3.5 to 4.0 mMol/L K: 4.4 mMol/L (with intense electrolyte protocol for supplementation 8 to 12 g of Magnesium Sulfate and 40 to 80 mMol/L KCL per day). PO4: 3.8 mg/dL. AST 35 ---> 101 U/L, ALT 36 U/L ---> 71 U/L, Bilirrubin Total: 0.5 mg/dL. U/A: trace proteinuria and (-) blood.
Renal US: bilateral cysts.
She uses total parental nutrition (TPN) for malnutrition and b/c issues with her stomach emptying function (California-Fowler Syndrome?). Has a diagnosis with Barrett’s esophagus for f/u with GI and using PPIs and h/o Headaches, migraines using NSAIDs at times, and painkillers.
MODY 5 Manifestations
Teaching Points:
1. Do not assume that the patient's diagnosis is proper.
2. If you have some questions, look for the answers.
3. Genetic disease is still a good portion of the pathology we see, especially in young patients with no classical presentations and now we have the ability to test it.
4. Use the resources to make the correct diagnosis, establish a prognosis, and plan for management.
5. A quotation in Spanish: "el que busca, encuentra". Translation: "Who looks, find it."