Duplication 6q24: More Than Just Diabetes

Chromosome 6q24-related transient neonatal diabetes mellitus is characterized by intrauterine growth restriction and low birth weight, with neonatal hyperglycemia resolving by 18 months and an increased risk for type 2 diabetes in adulthood. Molecularly, it is caused by overexpression of the 6q24 imprinted chromosomal region due to a duplication, uniparental disomy, or abnormal methylation. Conventional testing for this condition analyzes methylation patterns at the 6q24 locus but does not evaluate for the presence of other surrounding chromosomal abnormalities. We report a female with a history of neonatal hyperglycemia due to a paternally inherited duplication at chromosomal location 6q24. She subsequently presented to the pediatric genetics clinic at 15 months of age with developmental delay and abnormal balance. Microarray analysis identified a larger 14 Mb chromosomal duplication from 6q24 to 6q25.2, consistent with a diagnosis of duplication 6q syndrome. This case highlights the clinical importance of pursuing further genetic evaluation in patients diagnosed with chromosome 6q24-related neonatal hyperglycemia via targeted methylation-specific multiplex ligation-dependent probe amplification analysis identifying a duplication in this region. Early identification and intervention can improve developmental outcomes for patients with larger chromosome 6q duplications.

Neonatal hyperglycemia in a preterm infant managed with a subcutaneous insulin pump

Purpose Successful use of a subcutaneous insulin pump to administer regular insulin to a preterm infant with neonatal hyperglycemia is described. Summary A 520-g female infant born at 23 weeks’ gestational age via caesarian section was noted to have elevated blood glucose concentrations ranging up to 180 mg/dL (in SI units, 10 mmol/L) on day of life (DOL) 3 and peaking on DOL 9 at 250 mg/dL (13.9 mmol/L) despite conservative glucose infusion rates. Continuous infusion of regular insulin was begun on DOL 8 and continued through DOL 44, with an average insulin infusion rate of 0.08 units/kg/h. The patient experienced blood glucose concentration lability due to multiple factors, resulting in the need for frequent and routine blood glucose concentration monitoring to minimize hypoglycemia events. On DOL 44, a subcutaneous insulin pump was placed and used to provide diluted regular insulin (25 units/mL). After 1 week, the patient’s blood glucose concentration normalized, which led to a reduction in the frequency of glucose monitoring. After 3 weeks, insulin pump use was discontinued. The patient remained euglycemic thereafter. Conclusion The use of an insulin pump resulted in decreased blood glucose checks, discontinuation of central line access, and overall better patient care.

Az extrém alacsony születési súlyú koraszülöttek hyperglykaemiájának korai és késői szövődményei

Introduction: During recent decades, the perinatal mortality of extremely low-birth weight infants has decreased. An important task is to recognize complications of prematurity. Aim: We made an attempt to explore the relationship between complications of prematurity and neonatal hyperglycemia. Method: From 1 January 2014 to 31 December 2017, 188 infants with birth weight below 1000 g were admitted. For each infant, the frequencies of hyperglycemia (blood glucose >8.5 mmol/l), retinopathy of prematurity, intraventricular hemorrhage, and bronchopulmonary dysplasia were determined. Animal studies were performed in Sprague Dawley rats. Hyperglycemia was achieved by intraperitoneal injection of streptozotocin (100 mg/kg). On the 7th day of life, aorta sections were prepared and stained with hematoxylin eosin. Wall thickness was measured using QCapture Pro 7 image analysis software. Results: The mean ± SD gestational age and birth weight were 27.1 ± 2.2 weeks and 814.9 ± 151.9 g; 33 infants (17.5%) died. Hyperglycemia was confirmed in 62 cases (32.9%), and insulin treatment was given to 43 infants (22.8%). The gestational age and birth weight of the hyperglycemic infants were significantly lower (p<0.001), the incidence of severe retinopathy (p = 0.012) and the mortality of insulin-treated patients were higher (p = 0.02) than in normoglycemic infants. Among survivors (n = 155), we found by logistic regression analysis that hyperglycemia was a risk factor for severe retinopathy (p<0.001). In the rat model, neonatal hyperglycemia caused significant thickening of the aortic wall. Conclusion: Our studies indicate that hyperglycemia is common in extremely low birth-weight infants. Monitoring of these infants for retinopathy of prematurity, kidney dysfunction, and hypertension is recommended. Orv Hetil. 2019; 160(32): 1270–1278.