Policy Number: SRP 072
Policy Name: Monogenetic Diabetes Testing (MODY)
Status: NHS England commissioned
Effective Date: 1 April 2024
Next Review Date: 1 April 2026
Monogenetic Diabetes (Maturity Onset Diabetes of the Young) results from the inheritance of a mutation in a single gene, and accounts for 1-2% of the population in the UK with diabetes. Around 90% of cases are misdiagnosed as T1D or T2D.
All genetic testing is now centrally funded by NHS England for all NHS England patients. Clinicians can select genetic tests from a test directory, which will be performed and funded by NHS England if patients meet eligibility criteria. The test directory and eligibility criteria can be found at https://www.england.nhs.uk/publication/national-genomic-test-directories/
For monogenic diabetes testing, clinicians may request R141 for MODY and monogenic diabetes subtypes diagnosed outside of the neonatal period, R142 for GCK related hyperglycaemia, R143 for neonatal diabetes and R158 for lipodystrophy and insulin resistance syndromes. Exeter is the national provider for monogenic diabetes testing for NHS England.
Details of monogenic diabetes testing available in England can be found at https://www.diabetesgenes.org/what-is-mody/, and referral forms for testing can be found at https://www.diabetesgenes.org/genetic-test-referral-forms/
When to suspect a diagnosis of Type 1 may not be correct
- A diagnosis of diabetes before 6 months
- Family history of diabetes with a parent affected.
- Evidence of endogenous insulin production outside the ‘honeymoon’ phase with detectable C peptide
- When pancreatic islet autoantibodies are absent, especially if measured at diagnosis.
When to suspect a diagnosis of Type 2 may not be correct
- Not markedly obese or diabetic family members who are normal weight
- Acanthosis nigricans not detected.
- Ethnic background from a low prevalence Type 2 diabetes race e.g. European Caucasian
- No evidence of insulin resistance with fasting C peptide within the normal range
- Assessment for the patient using the link/calculator and documentation of the outcome: http://diabetesgenes.org/content/mody-probability-calculator
Find out more information on applying for funding in exceptional clinical circumstances.