A urine test that can be taken at home could help differentiate a diagnosis of type 1 diabetes from a genetic form of the disease, called maturity-onset diabetes of youth (MODY). Researchers from the Peninsula Medical School in United Kingdom, presented their findings at the 47th annual European Association for the Study of Diabetes (EASD) last week, and said that the test can help doctors pinpoint which children should undergo further genetic testing for MODY, which is sometimes misdiagnosed as type 1 diabetes in children. The study was previously published in the February 2011 issue of Diabetes Care.
MODY is a monogenic form of diabetes, which results from mutations in a single gene and is distinct from autoimmune type 1 diabetes, which is caused by a contribution from many genes. A number of different gene mutations have been shown to cause MODY, all of which limit the ability of the pancreas to produce insulin, leading to high blood sugar levels. Unlike people with type 1 diabetes who always require insulin, people with MODY can still secrete insulin and some can be treated with oral diabetes medications. MODY is typically diagnosed among people 25 years old and younger, and is discovered by taking a blood test. The standard test to determine a diagnosis of MODY is the mixed-meal tolerance test, which requires having to come to a doctor’s office or hospital and staying for two hours after a blood sample is drawn. Further information about testing to determine probability of the presence of MODY can be found at: http://www.diabetesgenes.org, a web site run by the researchers who conducted the study at the Centre for Molecular Genetics at the Peninsula Medical School and Royal Devon and Exeter Hospital, Exeter, UK. The site also includes a probability calculator, which can help doctors and patients determine a MODY diagnosis.
The urine test developed by the researchers was designed to be administered after eating a meal at home, and collecting the sample before it is mailed out to a lab where the after-meal ratio of urinary C-peptide to creatinine (UCPCR) is measured.
The researchers studied the test’s efficacy in 135 children under 18 years old diagnosed with type 1 diabetes, and 52 children diagnosed with MODY. The researchers found that the UCPCR ratio was significantly lower in the children with type 1 diabetes than in the children with MODY, who tended to have a more positive ratio because they are still producing insulin (measured by the c-peptide). Through these findings, the researchers concluded that a UCPCR ratio greater than 0.79 nmol/mmol identified MODY, and should be considered for further genetic testing.
While the group’s UCPCR test can be a simple way to help distinguish MODY from type 1 diabetes, some researchers say it still needs further validation for accuracy. Other researchers are already working to independently validate the test. It is also important to note the role that family history plays. According to the National Institute of Diabetes and Digestive and Kidney Diseases, family members of people with MODY are at an increased risk for the condition, and people with MODY typically have a family history of diabetes in multiple successive generations, which means that MODY is present in a grandparent, a parent, and a child. If you think that you or a family member may have a monogenic form of diabetes, please seek advice from your health care professional.
While JDRF did not fund this particular study, we continue to fund research to help understand the genetic causes of type 1 diabetes and how we may be able to prevent it.