Monogenic Diabetes Flashcards
definition of monogenic diabetes
rare type of diabetes caused by a single genetic mutation
accounts for
1-2% of all types of diabetes
2 main type
- maturity onset diabetes of the young (MODY)
2. neonatal diabetes
MODY is inherited
autosomal dominantly
in MODY there is usually
a strong 3 generation family history (although may be misdiagnosis of type 1 or type 2)
classically diagnosed
before the age of 25
MODY is caused by a
mutation in one of 12 genes split into 2 subgroups:
- MODY caused by glucokinase mutation
- MODY caused by hepatocyte nuclear factors mutation
MODY X
people who have MODY but the gene causing MODY has not yet been identified
mutations in glucokinase
causes the KM of glucokinase to be increased to around 7mmol/l (instead of normal which is 5) this means that more glucose is required to produce the same insulin response
glucokinase mutations
do not cause complications and requires no treatment as HbA1c levels are only very slightly raised
only time when glucokinase mutation may be a problem
in pregnancy is the mother has a glucokinase mutation but the foetus does not there is a greater chance of macrosomia (i.e. the baby will be overweight)
Most common HNF mutations
HNF-1 alpha and HNF-4 alpha
what is HNF
hepatocyte nuclear factors are transcription factors which affect beta cell function
HNF mutations
do cause complications and require treatment with sulfonylurea drugs
what are HNF mutations very similarly to clinically
type 2 diabetes mellitus so be careful not to misdiagnose
