BackgroundIn Korea, the prevalence of anemia and iron deficiency anemia (IDA) among older infants and young children remains high. To detect IDA early and to reduce its adverse impact, we assessed the characteristics of infants and young children who had IDA or were at risk of developing IDA, or who exhibited characteristics associated with severe anemia.MethodsAmong the 1,782 IDA-affected children aged 6 months to 18 years who visited the hospital, we retrospectively analyzed the medical records and laboratory data of 1,330 IDA-affected children aged 6–23 months who were diagnosed between 1996 and 2013. We excluded patients with a C-reactive protein level ≥5 mg/dL.ResultsIDA was predominant in boys (2.14:1) during infancy and early childhood. The peak IDA incidence was noted among infants aged 9–12 months. Only 7% patients exhibited symptoms of IDA, while 23.6% patients with severe IDA demonstrated classic symptoms/signs of IDA. Low birth weight (LBW) infants with IDA demonstrated low adherence to iron supplementation. In a multivariate analysis, prolonged breastfeeding without iron fortification (odds ratio [OR] 5.70), and a LBW (OR 6.49) were identified as risk factors of severe anemia.ConclusionLBW infants need more attention in order to increase their adherence to iron supplementation. For the early detection of IDA, nutritional status of all infants, and iron batteries of high-risk infants (LBW infants, infants with prolonged breastfeeding, picky eaters, and/or infants with the presence of IDA symptoms) should be evaluated at their health screening visits.

Both small for gestational age and large for gestational age (LGA) size at birth are associated with metabolic complications throughout life. The long-term consequences of LGA have been investigated in only a few studies. LGA is thought to be associated with early obesity and metabolic risk. Understanding how LGA can influence later obesity risk is important for pediatric obesity interventions. Pregnant women who are overweight or obese are at high risk of having LGA babies. Infants born LGA are at increased risk of becoming overweight or obese children, adolescents, and young adults and can have an increased risk of metabolic syndrome later in life and giving birth to LGA offspring. Education and intervention for weight control before and during pregnancy should be conducted to prevent LGA births. Particular attention is needed for women of childbearing age who are diabetic and obese, which could be the starting point for lifelong management of obesity.

BackgroundMcCune–Albright syndrome (MAS) is a rare disease defined by the triad of fibrous dysplasia (FD), café au lait spots, and peripheral precocious puberty (PP). Because of the rarity of this disease, only a few individuals with MAS have been reported in Korea. We describe the various clinical and endocrine manifestations and genetic analysis of 14 patients with MAS in Korea.MethodsPatients’ clinical data—including peripheral PP, FD, and other endocrine problems—were reviewed retrospectively. In addition, treatment experiences of letrozole in five patients with peripheral PP were described. Mutant enrichment with 3′-modified oligonucleotides - polymerase chain reaction (MEMO-PCR) was performed on eight patients to detect mutation in GNAS using blood. MEMO-PCR is a simple and practical method that enables the nondestructive selection and enrichment of minor mutant alleles in blood.ResultsThe median age at diagnosis was 5 years 2 months (range: 18 months to 16 years). Eleven patients were female, and three were male. Thirteen patients showed FD. All female patients showed peripheral PP at onset, and three patients subsequently developed central PP. There was a significant decrease in estradiol levels after two years of letrozole treatment. However, bone age was advanced in four patients. Two patients had clinical hyperthyroidism, and two patients had growth hormone (GH) excess with pituitary microadenoma. c.602G > A (p.Arg201His) in GNAS was detected in two patients in blood, and c.601C > T (p.Arg201Cys) in GNAS was detected in one patient in pituitary adenoma.ConclusionsThis study described the various clinical manifestations of 14 patients with MAS in a single center in Korea. This study first applied MEMO-PCR on MAS patients to detect GNAS mutation. Because a broad spectrum of endocrine manifestations could be found in MAS, multiple endocrinopathies should be monitored in MAS patients. Better treatment options for peripheral PP with MAS are needed.

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PurposeIn recent years, there has been an increasing focus on thyroid function in pediatric obese patients, but no nationwide study evaluating the relationship between thyroid function and obesity has yet been conducted in Korea. We aimed to evaluate thyroid dysfunction in obese Korean children.MethodsWe analyzed the associations between obesity and thyroid hormone levels among 975 Korean boys and girls aged 10–18 years and who participated in the Korean National Health and Nutrition Examination Survey VI (2013–2015).ResultsAverage serum thyrotropin (TSH) and serum free thyroxine (fT4) levels in the nonobese group were 2.7±0.1 μIU/mL and 1.3±0.0 ng/dL, respectively, and those in the overweight group were 3.1±0.2 μIU/mL and 1.2±0.0 ng/dL. Serum TSH level was significantly higher in the abdominal obesity group than in the normal group (P=0.023). fT4 level was significantly lower in both the overweight and abdominal obesity groups than in the normal group (P<0.001, P=0.014). Serum TSH level was associated positively with abdominal obesity and levels of high-density lipoprotein cholesterol and triglyceride. Serum fT4 level was negatively correlated with abdominal obesity (P=0.014).ConclusionsKorean children with abdominal obesity showed increased TSH and decreased fT4 levels compared to normal children.