Monogenic diabetes in children: An underdiagnosed and poorly managed clinical dilemma

Table 1 Types of monogenic diabetes and the affected genes

MODY	NDM	Mitochon-drial DM	Autoimmune monogenic DM	Insulin resistance syndromes	Lipodystrophy
MODY1 -HNF4A	Abnormal pancreatic development	MELAS	IPEX	Type A insulin resistance syndrome	Congenital generalized lipodystrophy
	PLAGL1	DMDF	FOXP3	Donohue and Rabson-Mendenhall syndromes – INSR
	HYMAI	MIDD
	ZFP57	Leigh syndrome SNHL
	PDX1	MM - m.3243A>G
	PTF1A
	PTF1A
	enhancer
	HNF1B
	RFX6
	GATA6
	GLIS3
	NEUROG3
	NEUROD1
	PAX6
MODY2 -GCK	MNX1				CGL1 - AGPAT2
MODY3 - HNF1A	NKX2-2	MELAS; possible atherosclerosis risk - m.3256C>T			CGL2 – BSCL2
MODY4 -PDX1	CNOT1	MMC/MELAS - m.3260A>G			CGL3 – CAV1
MODY5 - HNF1B	ONECUT1	MELAS/DM - m.3271T>C	Autoimmune polyglandular syndrome type 1 -AIRE	SHORT syndrome - PIK3R1	CGL4 - PTRF
MODY6 - NEUROD1	Abnormal beta-cell function	MERRF - m.8344A>G	IPEX-like” phenotype CTLA4	Other genetic abnormalities	Familial partial lipodystrophy
	KCNJ11		IL2RA	AKT2 TBC1D4
	ABCC8		ITCH	PRKCE
	INSC		LRBA
MODY7 -KLF11	GCK		Other autoimmune diabetes		FPLD2 - LMNA
MODY8 -CEL	SCLC2A2 (GLUT2)	MIDD, renal insufficiency - m.9155A>G	STAT1		FPLD3 - PPARG
MODY9 -PAX4	SLC19A2		STAT3		FPLD4 – PLN1
MODY10 -INS	KCNMA1		STAT5B		FPLD5 - CIDEC
MODY11 -BLK	Destruction of beta-cells	DMDF/RP + SNHL - m.12258C>A			FPLD6 - LIPE
	INS
	IER3IP1
	EIF2B1
	YIPF5
MODY12 -ABCC8	Wolcott-Rallison syndrome -EIF2AK3	MM + DMDF/Encephalomyopathy/Dementia + diabetes + ophthalmoplegia - m.14709T>C			FPLD7 – CAV1
MODY13 -KCNJ11	Wolfram syndrome - WFS1
MODY14 -APPL1

MODY: Maturity-onset diabetes of the young; CGL: Congenital generalized lipodystrophy; FPLD: Familial partial lipodystrophy; MELAS: Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes; DMDF: Diabetes mellitus and deafness; MIDD: Mitochondrial diabetes and deafness, MM: Mitochondrial Myopathy; MERRF: Myoclonic epilepsy and ragged red muscle fibers; MMC: Maternal myopathy and cardiomyopathy; RP: Retinitis pigmentosa; SNHL: Sensorineural hearing loss; NDM: Neonatal diabetes mellitus; IPEX: Immune dysregulation, polyendocrinopathy, enteropathy, X-linked.

Table 2 Clinical conditions suggestive of neonatal diabetes mellitus and for ordering genetic analysis

Rank	Clinical or laboratory context
1	Infant before 6 months of age with plasma glucoses persistently > 250 mg/dL (13.9 mmol/L) without an alternative etiology
2	Hyperglycemia persisting after seven to ten days of birth
3	Infants with extreme hyperglycemia i.e., plasma glucose > 1000 mg/dL (55.6 mmol/L)
4	Infants with diabetes diagnosed between 6 and 12 months, especially in those without islet autoantibodies or who have other features suggestive of a monogenic cause
5	Infants with transient diabetes mellitus1

¹Median age when treatment is not required is 12-14 wk in 6q24 anomalies.