Can Thi Bich Ngoc et al Department of Endocrinology, Metabolism and Genetics National Hospital of Pediatrics

Overview Hyperglycemia < 6 months of age (< 12 months) Two types: permanent and trasient Incidence: 1/ – 1/ live births Causes: gene mutation at ABCC8, KCNJ11, INS on chromsom 11, chromsom 6q anomalies, some other genes Children with mutations in KCNJ11 or ABCC8 can be transitioned to therapy with oral sulfonylureas

Loss of methylation on the maternally inherited allele within the imprinting control region causes TNDM Imprinted start site: I Karen Temple 2009

Overexpression of PLAGL1/HYMAI causes TNDM Paternal duplication at 6q24 33% Paternal uniparental disomy 6 (UPD6) 41% Loss of maternal methylation ‘ epigenetic mutation’ 26% I Karen Temple 2009

NDM due to K-ATP gene mutation Present in the first days/weeks of life, rarely > 6months: 50% have heterozygous activating mutation genes encoding K-ATP channel subunits GLUT2 glucose transporter glucose K ATP channel Sulfonylurea Glyon et al NEJM 2004

Objective Identify mutation of ABCC8; KCNJ11; INS, other genes and 6q hypomethylation of patients with neonatal diabetes. Evaluate of outcome the NDM patients with gene mutation.

Subjective 20/24 patients with diabetes mellitus < 12 months old at Vietnam National Hospital of Pediatrics Chose standard: persistent hyperglycemia > 150 – 200 mg/dl (> 8.3 – 11.1 mmol/l) in infants younger than age 12 months. Gene mutation at ABCC8, KCNJ11, INS, some other genes, 6q Chromosom 6 Except: hyperglycemia due to glucose infusion, infection, premature, no genes mutation

Methods Case series study, collect the symtoms and investigations DNA was extracted from lymphocyte and analysed gene mutation by PCR, sequencing or methylation- specific PCR of KCNJ11, ABCC8, INS, other genes and Chromosom 6q24. Patients with ABCC8, KCNJ11 mutation will be transfered to sulfonylureas

Results 20 patients with gene mutation, 4 patients in analysis progress MutationN% KCNJ11630 ABCC8525 INS420 Chr6q24420 IEF2AK315

Results Demographic Age of diagnosed: 73.7 ± 82.3 days (07 – 357 days, median 45) Gender: 10 males, 10 females Gestigation age: 39.1 ± 1.8 Birth weight: ±515.2 g (2000 – 3900 g): 11 cases (57.8%) < 3 pecentile

Results Clinical features and laboratory at diagnosis Diabetes keton acidosis: 13/20 cases pH 7.14 ±0.18 HCO ±8.8 mmo/l BE ±10.1 Đường máu: 35.3 ±10.5 (mmol/l) HbA1C: 7.89 ±2.78%. (%)

Results of mutation analysis GenecasePositionGenotypeMechanism KCNJ11 1Kir6.2 exon 1heter R201HMissense (p.Arg201His) 2, 12Kir6.2 exon 1heter R201Cmissense (p.Arg201Cys) 10Kir6.2 exon 1Heter. p.R50Q Missense p. Arg50Gln 14Kir 6.2 exon 1Heter p.E229K Missense p.Glu229Lys 16Kir6.2Heter p.E292Gp.Glu292Gly ABCC8 3SUR1 exon 1-39heter R1183W(p.Arg1147Trp) 4SUR1 exon 17homo E747Xnonsense 5SUR1 exon 17heter E747X & E128K Missense (c.382G>A) & nonsense (c.2239 T>G) 13Heter p.A1153G Đ ộ t bi ế n m ớ i 15 SUR 1 intron 27/exon 37 Heter c G>A & c.4519 G>C Splicing c G>A missense p.E1507Q

Results of mutation analysis GenecasePositionGenotypeMechanism Chr6 BN 66q hypomethylationZFP delT & 7812C>CT BN 86q hypomethylationZFP57 BN 11Loss of methylation BN 20Loss ofmethylation INS BN 7INS exon 2-3heter C43Sp.Cys43Ser BN 9, BN 18INS intron 2 heter C G>A Splicing BN 19INS heter C96R missense EIF2AK3 BN 17Exon 12 Het c.1894C>T missense

outcome 11 /11 cases with ABCC8 or KCNJ11 successful switching from Insulin to Oral Sulfonylureas Duration of insulin treatment: 28.6 ±32 months (2-86, median: 10.5); HbA1C: 8.5 ±2.7%, glucose 3-17 mmol/l Duration of SU treatment: 30 ± 16 months (7-51), HbA1C: 6.05 ± 0.8 (%), blood glucose 4-10 mmol/l 9 patients are normal mental development: DQ 80-85%, speech and movement improvement of two patients with DEND syndrome

Outcome 4/20 cases with Chr 6q anormalies stop insulin injection after treatment 18 – 4.5 – 4.5 – 6 months After 24.3 ± 10.2 months (13-33) of stop insulin: HbA1C: 5.2 ±0.8 %; fasting blood glucose: mmol/l, DQ % 4/20 cases with INS, 1/20 case with IEF2AK3 mutation have been continued insulin injection

Conclusion Most of NDM patients with gene mutation (20/24) In Vietnam we found the mutation at KCNJ11, ABCC8, INS and chr 6q anormalitites. 11/11 cases with ABCC8 or KCNJ11 mutation successful switching from Insulin to Oral Sulfonylureas 4/17 cases are TNDM Molecular diagnosis is required in neonatal diabetes mellitus.