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.