Dyshormonogenesis is caused by genetic defects in thyroid hormone synthesis. The most common form is thyroid peroxidase (TPO) deficiency. Clinically variable degree of hypothyroidism and thyroid gland enlargement depend on the severity of the defect. We report 22-year-old female with congenital hypothyroidism (CH) caused by TPO deficiency. Since goitrous CH was diagnosed at 8-year-old, L-thyroxine has been supplemented. Her goiter size was fluctuated according to the compliance on the medication. After 3.5 years of medication, ultrasonography found solid nodule, which was interpreted as nodular hyperplasia pathologically. The nodule size did not change during recent 10 years except peripheral calcification. Genetic analysis using NGS for CH revealed compound heterozygous variants of c.2757del;p.(Met921Trpfs*53) and c.1580G＞T;p.(Trp527Leu) in TPO gene. The first variant inherited from asymptomatic mother is pathogenic frame-shift mutation associated with stop codon, and the second one inherited from her asymptomatic father is predicted as deleterious in bioinformatics software program. From this case, we have observed that nodular change and calcification developed from diffuse enlarged goiter in dyshormonogenetic patient. Early molecular diagnosis of dyshormonogenesis and TSH suppression is important for not developing thyroid nodules in case of childhood euthyroid goiter without thyroid autoantibodies.

Primary hyperparathyroidism (PHPT) is a hypercalcemia disorder with inappropriately normal or increased serum parathyroid hormone (PTH) levels resulting from excessive secretion of PTH from one or more of the parathyroid glands. PHPT is uncommon in infants and children, with an estimated incidence of 2–5 cases per 100,000 persons. Patients with PHPT usually present with bone pain, urolithiasis, or nephrolithiasis, as well as nonspecific symptoms such as fatigue and weakness. Asymptomatic hypercalcemia may also be detected incidentally. Only a few cases of pediatric PHPT have been reported in Korea. We present three patients (a 9-year-old girl, a 14-year-old boy, and a 14-year-old girl) with PHPT who manifested variable clinical features of hypercalcemia. The first and second patients each had a parathyroid adenoma and presented with abdominal pain caused by pancreatitis and a ureter stone, respectively. The third patient had an ectopic mediastinal parathyroid adenoma and presented with gait disturbance and weakness of the lower extremities. All of the patients underwent surgical resection of parathyroid adenoma, and their serum calcium levels subsequently normalized without medication.

Dual oxidase maturation factor 2 (DUOXA2) is necessary for the enzymatic activity of dual oxidase 2 (DUOX2) to generate hydrogen peroxide production during thyroid hormone synthesis. We describe two Korean children, who were initially suspected to have transient congenital hypothyroidism (CH), but later confirmed to have permanent CH caused by DUOXA2 mutation. Treatment with levothyroxine was discontinued after confirming thyroid-stimulating hormone (TSH) level to be below 10 μU/mL and normal thyroid scan at the first or second trial-off therapy. However, after therapy cessation, TSH elevated to more than 10 μU/mL, and goiter developed in case 2. As a result, levothyroxine was resumed. Next-generation sequencing showed compound heterozygous mutations of DUOXA2 at Y138X and Y246X in case 1 and homozygous mutations of DUOXA2 at Y246X in case 2. In this report, a longer follow-up is recommended even after treatment termination in transient CH, and genetic studies might help assess the permanence of hypothyroidism in cases of mildly elevated TSH after trial-off therapy.

Background: The impact of the coronavirus disease 2019 (COVID-19) pandemic on Kawasaki disease (KD) has not yet been established. We investigated changes in the observed number and severity of KD cases and accompanying coronary artery complications during the COVID-19 pandemic in Korea. Methods: This retrospective observational study included patients aged < 18 years with acute-phase KD diagnosed between March 2018 and February 2021. Data were extracted from the Clinical Data Warehouse that houses data from five affiliated university hospitals in Korea. We analyzed changes in the number of patient admissions and clinical characteristics, including cardiac complications, before and after the onset of the COVID-19 pandemic. Results: A total of 475 admissions were included in the analysis. After March 2020, we observed a significant decrease of 33% in the number of hospitalizations for KD compared with the average number of hospitalizations during the previous 2 years. The number of admissions per month significantly decreased by 7.9 persons/month (95% confidence interval, −13.8 to −2.0; P < 0.05) compared with that before COVID-19. By contrast, the proportion of patients aged < 1 year with KD increased. The proportion of patients with refractory KD and the rate of cardiac complications did not change significantly. Conclusion Since the onset of the COVID-19 pandemic, the total number of hospital admissions for KD has decreased in Korea. Although the proportion of admissions of infants aged < 1 year increased, no changes were observed in clinical courses and complications.

Purpose: Oral supplementation of vitamin D can be inefficient in patients with vitamin D deficiency caused by intestinal malabsorption. This study investigated the efficacy and safety of parenteral vitamin D supplementation in infants and children with vitamin D deficiency caused by intestinal malabsorption. Methods: This study included 11 patients with vitamin D deficiency who were unresponsive to oral vitamin D or were unable to try oral vitamin D therapy due to underlying conditions. All patients were treated with weekly intramuscular injection of cholecalciferol 50,000 IU. Radiological findings and biochemical parameters including serum calcium, phosphorus, alkaline phosphatase, 25-hydroxyvitamin D3 (25(OH)D3), and parathyroid hormone levels were reviewed retrospectively. Results: Underlying diseases included small bowel atresia (n=3), necrotizing enterocolitis (n=3), congenital megacolon (n=2), chronic intestinal pseudoobstruction (n=1), congenital mesenteric band (n=1), and Crohn disease (n=1). Three patients exhibited rickets on X-ray findings. The mean duration of treatment was 4.8±2.9 weeks. The alkaline phosphatase levels were decreased from 710±650 IU/L to 442±284 IU/L (P=0.143). The 25(OH)D3 level was increased from 6.0±3.4 ng/mL to 50.4±28.8 ng/mL (P=0.008) after 3 months. Two patients with rickets showed improved radiologic findings after parenteral treatment. Conclusion Parenteral vitamin D therapy was effective and safe in patients with vitamin D deficiency caused by intestinal malabsorption. Long-term follow-up is needed to establish the efficacy of parenteral vitamin D therapy in a large number of patients.

Purpose: Cytochrome P450 oxidoreductase (POR) deficiency is a rare autosomal recessive disorder caused by mutations in the POR gene encoding an electron donor for all microsomal P450 enzymes. It is characterized by adrenal insufficiency, ambiguous genitalia, maternal virilization during pregnancy, and skeletal dysplasia. In this study, we investigated the clinical, hormonal, and molecular characteristics of patients with POR deficiency in Korea. Methods: This study included four patients with POR deficiency confirmed by biochemical and molecular analysis of POR. Clinical and biochemical findings were reviewed retrospectively. Mutation analysis of POR was performed by Sanger sequencing after polymerase chain reaction amplification of all coding exons and the exon-intron boundaries. Results: All patients presented with adrenal insufficiency and ambiguous genitalia regardless of their genetic sex. Two patients harbored homozygous p.R457H mutations in POR and presented with adrenal insufficiency and genital ambiguity without skeletal phenotypes. The other two patients with compound heterozygous mutations of c.[1329_1330insC];[1370G>A] (p.[I444Hfs*6];[R457H]) manifested skeletal abnormalities, such as craniosynostosis and radiohumeral synostosis, suggesting Antley-Bixler syndrome. They also had multiple congenital anomalies involving heart, kidney, and hearing ability. All patients were treated with physiologic doses of oral hydrocortisone. Conclusion We report the cases of 4 patients with POR deficiency identified by mutation analysis of POR. Although the study involved a small number of patients, the POR p.R457H mutation was the most common, suggesting founder effect in Korea. POR deficiency is rare and can be misdiagnosed as 21-hydroxylase or 17α-hydroxylase/17,20-lyase deficiency. Therefore, molecular analysis is critical for confirmatory diagnosis.

PURPOSE: Potocki–Lupski syndrome (PTLS), is a recently identified, rare genomic disorder. The patients are affected by infantile hypotonia, poor growth and developmental delay. Facial dysmorphism may not be obvious in some patients. PTLS is associated with microduplication at chromosome 17p11.2. In the current study, three Korean patients are reported with their clinical and genetic features. MATERIALS AND METHODS: The clinical findings of each patient were reviewed. Karyotyping and multiplex ligation-dependent probe amplification (MLPA) analyses were done for genetic diagnoses. RESULTS: All the patients did not have the characteristic dysmorphic features, such as broad forehead, triangular face, asymmetric smile and palpebral fissures. On the other hand, all three patients were affected by variable degree of developmental delay, poor oral intake, failure to thrive, and language development disorders. Chromosome 17p11.2 duplication was identified by conventional karyotyping analysis only in one patient, whereas the other confirmed by MLPA analyses. CONCLUSION Delayed development was mostly commonly observed in our patients without distinct dysmorphic facial features. In this respect, genomic screening in patients with developmental delay would identify more cases with PTLS to understand their long-term clinical courses with the development of adequate psychological and rehabilitation education program.

KBG syndrome is an autosomal dominant syndrome presenting with macrodontia, distinctive facial features, skeletal anomalies, and neurological problems caused by mutations in the ankyrin repeat domain 11 (ANKRD11) gene. The diagnosis of KBG is difficult in very young infants as the characteristic macrodontia and typical facial features are not obvious. The youngest patient diagnosed to date was almost one year of age. We here describe a 2-month-old Korean boy with distinctive craniofacial features but without any evidence of macrodontia due to his very early age. He also had a congenital megacolon without ganglion cells in the rectum. A de novo deletion of exons 5–9 of the ANKRD11 gene was identified in this patient by exome sequencing and real-time genomic polymerase chain reaction. As ANKRD11 is involved in the development of myenteric plexus, a bowel movement disorder including a congenital megacolon is not surprising in a patient with KBG syndrome and has possibly been overlooked in past cases.
Ankyrin Repeat ; Diagnosis ; Exome ; Exons ; Ganglion Cysts ; Hirschsprung Disease ; Humans ; Infant ; Male ; Movement Disorders ; Myenteric Plexus ; Polymerase Chain Reaction ; Rectum

PURPOSE: Patients with ovotesticular disorder of sex development (DSD) and mixed gonadal dysgenesis (MGD) usually present with asymmetric gonads and have wide phenotypic variations in internal and external genitalia. The differential diagnosis of these conditions is based on karyotype and pathological findings of the gonads. This study investigated the clinical features at presentation, karyotype, sex of rearing, and pubertal outcomes of patients with ovotesticular DSD and MGD.METHODS: The study comprised 23 patients with DSD who presented with asymmetric gonads. The presenting features, karyotype, sex of rearing, and pubertal outcomes were reviewed retrospectively.RESULTS: All 23 patients presented with ambiguous genitalia at a median age of 1 month (range, 1 day–1.6 years). Müllerian duct remnants were identified in 15 of 23 patients (65.2%). Fourteen patients were diagnosed with ovotesticular DSD, whereas the other 9 were diagnosed with MGD. Eight of 14 patients (57.1%) with ovotesticular DSD were raised as males, while 7 of 9 patients with MGD (77.8%) were assigned as males. One male-assigned patient with ovotesticular DSD changed to female sex at age 20 years.CONCLUSION: Patients with ovotesticular DSD and MGD manifest overlapping clinical presentations and hormonal profiles. It is difficult to determine the sex of rearing and predict long-term pubertal outcomes. Therefore, long-term follow-up is required to monitor spontaneous puberty, sex outcome, and urological and gynecological complications.
Adolescent ; Diagnosis, Differential ; Disorders of Sex Development ; Female ; Follow-Up Studies ; Genitalia ; Gonadal Dysgenesis ; Gonadal Dysgenesis, Mixed ; Gonads ; Humans ; Karyotype ; Male ; Ovotesticular Disorders of Sex Development ; Puberty ; Retrospective Studies

X-linked juvenile retinoschisis (XLRS) is characterized by the progressive loss of visual acuity and vitreous hemorrhage. XLRS is caused by a mutation of retinoschisin 1 (RS1) gene at Xp22.13. In the current report, a 2-year-old Korean patient with XLRS was described. The germline deletion of exon 1 was identified in the RS1 gene. Considering X-linked inheritance pattern, validation of a carrier state of a patient's mother is important for the genetic counseling of other family members and for the future reproductive plan. To confirm the carrier state of his mother, the multiplex ligation-dependent probe amplification analysis was done using peripheral leukocytes and found the heterozygous deletion of exon 1 in his mother.
Carrier State ; Child, Preschool ; Exons ; Genes, X-Linked ; Genetic Counseling ; Humans ; Leukocytes ; Mothers ; Multiplex Polymerase Chain Reaction ; Retinoschisis* ; Visual Acuity ; Vitreous Hemorrhage