Steroid 21-hydroxylase deficiency is the most prevalent form of congenital adrenal hyperplasia (CAH), accounting for approximately 95% of cases. With the advent of newborn screening and hormone replacement therapy, most children with CAH survive into adulthood. Adolescents and adults with CAH experience a number of complications, including short stature, obesity, infertility, tumor, osteoporosis, and reduced quality of life. Transition from...

Turner syndrome (TS) is a genetic disorder in phenotypic females that has characteristic physical features and presents as partial or complete absence of the second sex chromosome. Growth hormone deficiency (GHD) is a condition caused by insufficient release of growth hormone from the pituitary gland. The concomitant occurrence of TS and GHD is rare and has not yet been reported...

X-linked agammaglobulinemia (XLA) is a hereditary humoral immunodeficiency that results from Bruton’s tyrosine kinase (BTK) gene mutations. These mutations cause defects in B-cell development, resulting in the virtual absence of these lymphocytes from the peripheral circulation. Consequently, this absence leads to a profound deficiency of lg all isotypes, and an increased susceptibility to encapsulated bacterial infections. A 15-month-old Korean boy...

We report here a case of maternal 3-methylcrotonyl-coenzyme A carboxylase (3-MCC) deficiency in a Korean woman. Her 2 infants had elevated 3-hydroxyisovalerylcarnitine (C5-OH) on a neonatal screening test by liquid chromatography-tandem mass spectrometry (LC-MS/MS), but normal results were found on urine organic acid analysis. The patient was subjected to serial testing and we confirmed a maternal 3-MCC deficiency by blood...

Glucose transport 1 (GLUT-1) deficiency is a rare syndrome caused by mutations in the glucose transporter 1 gene (SLC2A1) and is characterized by early-onset intractable epilepsy, delayed development, and movement disorder. De novo mutations and several hot spots in N34, G91, R126, R153, and R333 of exons 2, 3, 4, and 8 of SLC2A1 are associated with this condition. Seizures,...

Wernicke's encephalopathy is an acute neurological disorder characterized by mental confusion, oculomotor dysfunction, and ataxia. It has been reported in individuals with alcohol dependence, hyperemesis gravidarum, and prolonged parenteral nutrition without vitamin supplementation. Here we present the case of a 13-year-old male patient with neuroblastoma and a history of poor oral intake and nausea for 3 months. After admission, he...

Iron deficiency affects approximately one-third of the world's population, occurring most frequently in children aged 6 months to 3 years. Mechanisms of iron absorption are similar to those of other divalent metals, particularly manganese, lead, and cadmium, and a diet deficient in iron can lead to excess absorption of manganese, lead, and cadmium. Iron deficiency may lead to cognitive impairments...

Vitamin D is an essential component of bone and mineral metabolism; its deficiency causes growth retardation and skeletal deformities in children and osteomalacia and osteoporosis in adults. Hypovitaminosis D (vitamin D insufficiency or deficiency) is observed not only in adults but also in infants, children, and adolescents. Previous studies suggest that sufficient serum vitamin D levels should be maintained in...

Prader-Willi syndrome (PWS) is a complex multisystem genetic disorder characterized by hypothalamic-pituitary dysfunction. The main clinical features include neonatal hypotonia, distinctive facial features, overall developmental delay, and poor growth in infancy, followed by overeating with severe obesity, short stature, and hypogonadism later in development. This paper reviews recent updates regarding the genetic aspects of this disorder. Three mechanisms (paternal deletion,...

Ornithine transcarbamylase (OTC) deficiency is well known as the most common inherited disorder of the urea cycle, and 1 of the most common causes of hyperammonemia in newborns. We experienced a case of a 3-day-old boy with OTC deficiency who appeared healthy in the first 2 days of life but developed lethargy and seizure soon afterwards. His serum ammonia level...

Breastfeeding is the best source of nutrition for every infant, and exclusive breastfeeding for 6 months is usually optimal in the common clinical situation. However, inappropriate complementary feeding could lead to a nutrient-deficient status, such as iron deficiency anemia, vitamin D deficiency, and growth faltering. The recent epidemic outbreak of obesity in Korean children emphasizes the need for us to...

Congenital factor VII deficiency is a rare autosomal-recessive bleeding disorder. Bleeding manifestations and clinical findings vary widely, ranging from asymptomatic subjects to patients with hemorrhages that may cause significant handicaps. Treatment has traditionally involved factor VII(FVII) replacement therapy using fresh frozen plasma, prothrombin complex concentrates or plasma-derived FVII concentrates. Recombinant activated FVII (NovoSeven®) is currently considered the first-line treatment for...

Anemia caused by vitamin B12 deficiency resulting from inadequate dietary intake is rare in children in the modern era because of improvements in nutritional status. However, such anemia can be caused by decreased ingestion or impaired absorption and/or utilization of vitamin B12. We report the case of an 18-year-old man with short stature, prepubertal sexual maturation, exertional dyspnea, and severe...