OBJECTIVES: This study aimed to evaluate a fixed-duration algorithm for gestational age (GA) estimation according to pregnancy outcomes and to describe the GA distribution of pregnancy-related codes in Korea. METHODS: We included 351,055 pregnancy episodes (2019–2022) from linked data between the National Health Insurance Service and the Korea Immunization Registry Information System (KIRIS). GA from claims data was estimated by subtracting fixed durations from the delivery date (algorithm-based GA), and GA derived from KIRIS was defined as the gold standard. Accuracy was evaluated as the proportion of episodes in which the difference between the estimated GA and the reference standard fell within ±2 weeks. We described the distributions of the GA at which each prenatal test, pregnancy complication, and diagnostic code was recorded. RESULTS: Algorithm-based GA estimation showed high accuracy for live births (92.2% within ±2 weeks) but markedly lower accuracy for non-live birth outcomes, including stillbirth (3.3%), termination (7.2%), spontaneous abortion (45.2%), and ectopic pregnancy (20.0%). In additional analyses aimed at identifying potential indicators for improving GA estimation, most events occurred within clinically expected timeframes, although some individual codes exhibited poor temporal alignment. CONCLUSIONS Algorithm-based GA estimation using claims data performed well for live births but demonstrated limited accuracy for non-live birth outcomes. Incorporating information from prenatal tests and pregnancy complications may enhance GA estimation.

Familial male-limited precocious puberty (FMPP) is a rare form of gonadotropin-independent precocious puberty that is caused by an activating mutation of the LHCGR gene. Herein, we report a case of FMPP with a mutation of the LHCGR gene in a Korean boy with familial history of precocious puberty through 3 generations. A 16-month-old boy presented with signs of precocious puberty, including pubic hair, acne, and increased growth velocity. The patient's grandfather and father had a history of precocious puberty and profound short stature. On physical examination, the patient had prepubertal testes with pubic hair development appropriate for Tanner stage II. The stretched penile length was 7 cm (>2 standard deviation score), and observed bone age was that of a 4-year-old boy. Laboratory findings showed high serum testosterone (5.74 ng/mL [appropriate for Tanner IV–V]; normal range, <0.05 ng/mL) with suppressed luteinizing hormone (<0.07 mIU/mL) and normal serum level of follicular stimulating hormone (0.56 mIU/mL; normal range, 0.38–1.11 mIU/mL). Genetic testing revealed a pathogenic variant of LHCGR (c.1730 C>T (p.Thr577Ileu)), confirming FMPP. Bicalutamide and anastrozole were administered, and pubertal progression was sufficiently suppressed without any specific side effects. To our knowledge, this is the first case of genetically confirmed FMPP in Korea.

Rhabdomyolysis associated with psychogenic polydipsia and hyponatremia is a rare condition that can cause substantial morbidity and mortality. We report a 14-year-old boy with psychogenic polydipsia who experienced recurrent hyponatremia and subsequent rhabdomyolysis. Treatment involved intravenous fluids and restriction of oral water intake. This case emphasizes the importance of early recognition and management of this condition. The possibility of rhabdomyolysis should be considered in patients with hyponatremia who have myalgia.

Background: Discontinuing growth hormone (GH) treatment during the transition to adulthood has been associated with adverse health outcomes in patients with childhood-onset growth hormone deficiency (CO-GHD). This study investigated the metabolic changes associated with interrupting GH treatment in adolescents with CO-GHD during the transition period. Methods: This study included 187 patients with CO-GHD who were confirmed to have adult GHD and were treated at six academic centers in Korea. Data on clinical parameters, including anthropometric measurements, metabolic profiles, and bone mineral density (BMD) at the end of childhood GH treatment, were collected at the time of re-evaluation for GHD and 1 year after treatment resumption. Results: Most patients (n=182, 97.3%) had organic GHD. The median age at treatment discontinuation and re-evaluation was 15.6 and 18.7 years, respectively. The median duration of treatment interruption was 2.8 years. During treatment discontinuation, body mass index Z-scores and total cholesterol, low-density lipoprotein, and non-high-density lipoprotein (HDL) cholesterol levels increased, whereas fasting glucose levels decreased. One year after GH treatment resumption, fasting glucose levels, HDL cholesterol levels, and femoral neck BMD increased significantly. Longer GH interruption (>2 years, 60.4%) resulted in worse lipid profiles at re-evaluation. The duration of interruption was positively correlated with fasting glucose and non-HDL cholesterol levels after adjusting for covariates. Conclusion GH treatment interruption during the transition period resulted in worse metabolic parameters, and a longer interruption period was correlated with poorer outcomes. GH treatment should be resumed early in patients with CO-GHD during the transition period.

Purpose: Osteogenesis imperfecta (OI) is a rare bone fragility disorder caused by defects in type 1 collagen biosynthesis. This study investigated the genotype-phenotype correlations and the efficacy of pamidronate therapy in patients with OI in a single academic center. Methods: This study included 24 patients with OI. A clinical scoring system was used to evaluate disorder severity. COL1A1 and COL1A2 genes were analyzed in 13 patients using Sanger sequencing. Genotype-phenotype correlations and the efficacy of pamidronate therapy were analyzed through a retrospective medical chart review. Results: Of the 24 patients, 18 (75%) were classified as type I (12 with type Ia and 6 with type Ib), 2 as type III (8.4%), and 4 as type IV (16.7%). Type Ia patients showed relatively higher lumbar bone mineral density (BMD) standard deviation scores (SDS) and lower clinical scores than those with other types. Seven patients with qualitative mutations had lower lumbar BMD-SDS (P=0.015) and higher clinical scores (P=0.008) than 6 patients with quantitative mutations. The annual fracture frequency and lumbar BMD-SDS improved in patients with qualitative mutations after pamidronate treatment. Conclusion This study demonstrated that OI patients with qualitative mutations in COL1A1/2 had a more severe phenotype than those with quantitative mutations. Patients with qualitative mutations showed a significant reduction in fracture frequency and an increase in lumbar BMD-SDS after pamidronate treatment. Clinical score and genotype might be helpful for predicting phenotype and response to pamidronate therapy in OI patients.

Purpose: Osteoporosis is a skeletal disorder characterized by reduced bone mass that results in increased risk of fractures. Pediatric osteoporosis can be caused by monogenic diseases, chronic diseases, and/or their treatment. This study was performed to investigate the effect of pamidronate infusion on osteoporosis in children and adolescents. Methods: This study included 13 unrelated pediatric patients (10 males and 3 females) whose bone mineral density (BMD) z-score was <-2.0. Pamidronate was administered intravenously at a dosage of 1 mg/kg for 3 consecutive days every 4 months. Clinical and biochemical findings were reviewed retrospectively. The BMD values of the lumbar spine and femoral neck were assessed by dual energy x-ray absorptiometry at baseline and annually. Results: The underlying diseases were immobilization (62%), inflammatory bowel disease (23%), protein-losing enteropathy (8%), and idiopathic juvenile osteoporosis (8%). The mean age at the start of treatment was 12.7±4.3 years. Duration of treatment ranged from 12–50 months. The baseline height-standard deviation score (SDS) and weight-SDS were -2.01±2.08 and -2.60±1.62, respectively. The lumbar spine BMD z-scores improved significantly after 1 year of pamidronate treatment, but the femoral neck BMD z-scores did not. However, both z-scores had significantly increased by the end of treatment. Conclusion This study demonstrated that pamidronate treatment increased BMD in pediatric patients with osteoporosis with no significant adverse events. Further studies are required to better define the long-term efficacy and safety of pamidronate therapy in a large number of pediatric patients.

Purpose: Osteoporosis is a skeletal disorder characterized by reduced bone mass that results in increased risk of fractures. Pediatric osteoporosis can be caused by monogenic diseases, chronic diseases, and/or their treatment. This study was performed to investigate the effect of pamidronate infusion on osteoporosis in children and adolescents. Methods: This study included 13 unrelated pediatric patients (10 males and 3 females) whose bone mineral density (BMD) z-score was <-2.0. Pamidronate was administered intravenously at a dosage of 1 mg/kg for 3 consecutive days every 4 months. Clinical and biochemical findings were reviewed retrospectively. The BMD values of the lumbar spine and femoral neck were assessed by dual energy x-ray absorptiometry at baseline and annually. Results: The underlying diseases were immobilization (62%), inflammatory bowel disease (23%), protein-losing enteropathy (8%), and idiopathic juvenile osteoporosis (8%). The mean age at the start of treatment was 12.7±4.3 years. Duration of treatment ranged from 12–50 months. The baseline height-standard deviation score (SDS) and weight-SDS were -2.01±2.08 and -2.60±1.62, respectively. The lumbar spine BMD z-scores improved significantly after 1 year of pamidronate treatment, but the femoral neck BMD z-scores did not. However, both z-scores had significantly increased by the end of treatment. Conclusion This study demonstrated that pamidronate treatment increased BMD in pediatric patients with osteoporosis with no significant adverse events. Further studies are required to better define the long-term efficacy and safety of pamidronate therapy in a large number of pediatric patients.