Table 3.2.

Some examples of single recessive dominant genes as exemplified by maturity onset diabetes of the young (MODY) which is associated with metabolic syndrome disorder as observed in T2DM

Gene	Type of MODY	Genetic defect	Metabolic disorder	Clinical features
Hepatocyte nuclear factor 4α	MODY 1	Autosomal dominant	Impaired insulin secretion	Rare and progressive form of early onset disease
Glucokinase	MODY 2	Autosomal dominant	Impaired insulin secretion	Mild and relatively stable early onset disease
Hepatocyte nuclear factor 1α	MODY 3	Autosomal dominant	Impaired insulin secretion	Progressive form of early onset disease
Pancreatic duodenal homeobox factor-1	MODY 4	Autosomal dominant	Impaired insulin secretion	Early onset disease
Mitochondrial DNA	–	Maternal DNA	Impaired insulin secretion	Diabetes associated with deafness
Insulin	–	Autosomal dominant	Defective insulin production	Very rare
Insulin receptor	–	Autosomal dominant or recessive	Impaired insulin signaling pathway	Severe insulin resistance