Table 4.

Classification of diabetes

1	Type 1 diabetes mellitus: diabetes caused by insulin deficiency due to β-cell destruction
	1-1. Immune-mediated
	1-2. Idiopathic
2	Type 2 diabetes mellitus: diabetes caused by insulin resistance and progressive insulin secretion defect
3	Gestational diabetes mellitus: diabetes diagnosed during pregnancy
4	Other diabetes
	4-1. Genetic defects in β-cell function
	MODY3 (chromosome 12, HNF-1α), MODY1 (chromosome 20, HNF-4α), MODY2 (chromosome 7, glucokinase)
	Other rare forms of MODY (MODY4: chromosome 13, IPF-1; MODY5: chromosome 17, HNF-1β; MODY6: chromosome 2, NeuroD1; MODY7: chromosome 2, KLF11; MODY8: chromosome 9, CEL; MODY9: chromosome 7, PAX5; MODY10: chromosome 11, INS; MODY11: chromosome 8, BLK), transient neonatal diabetes (chromosome 6, ZAC/HYAMI imprinting defect), permanent neonatal diabetes (KCNJ11 gene encoding Kir6.2 subunit of β-cell KATP channel), mitochondrial DNA
	4-2. Genetic defects in insulin action
	Type A insulin resistance, leprechaunism, Rabson-Mendenhall syndrome, lipoatrophic diabetes
	4-3. Diseases of the exocrine pancreas
	Pancreatitis, trauma/pancreatectomy, neoplasia, cystic fibrosis, hemochromatosis, fibrocalculous pancreatopathy
	4-4. Endocrinopathies
	Acromegaly, Cushing’s syndrome, glucagonoma, pheochromocytoma, hyperthyroidism, somatostatinoma, aldosteronoma
	4-5. Liver disease: chronic hepatitis, cirrhosis
	4-6. Drug- or chemical-induced
	Vacor, pentamidine, glucocorticoids, nicotinic acid, thyroid hormone, diazoxazole, β-adrenergic agonist, thiazides, dilantin, γ-interferon, atypical antipsychotics (olanzapine, clozapine, risperidone, etc.), immune checkpoint inhibitor
	4-7. Infections: congenital rubella, cytomegalovirus, others
	4-8. Uncommon forms of immune-mediated diabetes
	Stiff-man syndrome, anti-insulin receptor antibodies
	4-9. Other genetic syndromes sometimes associated with diabetes
	Down’s syndrome, Klinefelter’s syndrome, Turner’s syndrome, Wolfram’s syndrome, Friedreich’s ataxia, Huntington’s chorea, Laurence-Moon-Biedl syndrome, myotonic dystrophy, porphyria, Prader-Willi syndrome

MODY, maturity onset diabetes of the young; HNF, hepatocyte nuclear factor; IPF-1, insulin promoter factor 1; KLF11, KLF transcription factor 11; CEL, carboxyl ester lipase; PAX5, paired box 5; INS, insulin; BLK, BLK proto-oncogene, src family tyrosine kinase; ZAC/HYAMI, zinc finger protein associated with apoptosis and cell cycle arrest/imprinted in hydatidiform mole; KCNJ11, potassium inwardly rectifying channel subfamily J member 11.