We analyzed the effects of age and sex on the relationship between muscle mass and serum creatinine levels in an apparently healthy population, including older adults. We retrospectively evaluated 1,502 individuals from the Korea National Health and Nutrition Examination Survey (KNHANES) and 4,586 individuals from the Health Check (HC) groups. We utilized data from the KNHANES and HC groups on serum creatinine levels and skeletal muscle mass index (SMI), determined using dual X-ray absorptiometry or bioelectric impedance analysis. A significant negative correlation between SMI and age was observed in both the KNHANES and HC groups in males but not in females. In males, serum creatinine levels showed a significant negative correlation with age in both the KNHANES (r = −0.522, P < 0.0001) and HC groups (r = −0.451, P < 0.0001). In females, there was no significant correlation between serum creatinine levels and age in the KNHANES (r = −0.016, P = 0.5985) and HC group (r = −0.011, P = 0.5618). Serum creatinine levels decrease more significantly in older males than in older females due to sex-specific muscle mass decline.

Childhood adrenocortical carcinoma (ACC) is a rare disease that is mostly linked to familial cancer syndrome. Although the prevalence of ACC is extremely low in children, it is clinically important to diagnose ACC early because age and tumor stage are closely related to prognosis. From this perspective, understanding the underlying genetics and possible symptoms of ACC is crucial in managing ACC with familial cancer syndromes. In this report, we present the case of a 3-year-old girl who initially presented with symptoms of precocious puberty and was later found to have ACC by imaging analysis. On genetic analysis, the patient was found to have a MEN1 gene mutation. MEN1 mutations are found in patients with multiple endocrine neoplasia type 1 (MEN1), usually precipitating multiple endocrine tumors, including pituitary adenoma, parathyroid hyperplasia, and adrenal tumors. Although MEN1 mutation is usually inherited in an autosomal dominant manner, neither of the patient’s parents had the same mutation, making hers a case of sporadic MEN1 mutation with initial presentation of ACC. The clinical course and further investigations of this patient are discussed in detail in this report.

Rationale: Osteopathia striata with cranial sclerosis is characterized by linear striations in the metaphysis of the long bones and pelvis with cranial sclerosis. It is an X-linked dominant sclerosing bone dysplasia and affected males show fetal or neonatal lethality. Mutations in the gene encoding Wilms tumor on the X chromosome (WTX) was identified as the cause of X-linked osteopathia striata with cranial sclerosis. About 30 pathogenic mutations in WTX have been reported recently. We have identified a novel nonsense mutation in the family diagnosed as osteopathia striata with cranial sclerosis. Patient concerns: The proband came to our attention at age 9 for the evaluation of toe-out gait and planovalgus deformity. Clinically, the proband showed coarse facial features including frontal bossing, ocular hypertelorism, wide depressed nasal bridge, dental malocclusion, mild macrocephaly and low set ears. Radiologically, sclerotic linear striations were seen in the X-rays of the pelvis and the metaphyseal region of femur and tibia and the cranial sclerosis was observed. The proband's mother presented similar facial features and the X-rays of the pelvis, femur, and tibia revealed same sclerotic linear striations as the proband's. Diagnoses: Osteopathia striata with cranial sclerosis. Interventions: A genetic analysis was conducted on genomic DNA isolated from peripheral blood leukocytes of the proband and the mother for confirming the clinical suspicion of osteopathia striata with cranial sclerosis. WTX on Xq11.2 gene was analyzed in direct sequencing for coding exons including intron-exon boundaries. Outcomes: One novel nonsense mutation (c.1003C>T, p.Gln335^∗) and known single nucleotide variant were observed in a heterozygous form. Lessons: We found a novel nonsense mutation in a family diagnosed as osteopathia striata with cranial sclerosis. The relationship between various clinical features and genetic mutations can be clarified by accumulation of genetic database.

18p deletion (18p-) syndrome is a rare chromosome abnormality that has a wide range of phenotypes, with short stature, intellectual disability, and facial dysmorphism being the main clinical features. Here, we report the first case in Korea of a 16-year-old male adolescent with 18p- syndrome resulting from de novo unbalanced whole-arm translocation between chromosomes 13 and 18 (45, XY, der(13;18)(q10:q10)). Three rare clinical findings were discovered that had not been reported in the previous literature; morbid obesity without other hormonal disturbances, rib cage deformity leading to the direct compression of the liver, and lumbar spondylolisthesis at the L5-S1 level. This case expands the phenotypic spectrum of 18p- syndrome and highlights the importance of considering chromosomal analysis, since this syndrome can be easily overlooked in a clinical setting, especially without distinctive symptoms of other organs, due to its nonspecific but typical features of short stature and mild intellectual disability with a mildly dysmorphic face. Moreover, since not all cases of 18p- syndrome with unbalanced translocation (13;18) show the same phenotype, multidisciplinary examinations and follow-up seem to be important to monitor evolving and developing clinical manifestations and to predict prognosis in advance associated with the specific genes of 18p breakpoint regions.

Plasma-free metanephrines are the most sensitive and specific biochemical markers for diagnosing catecholamine-secreting tumors, such as pheochromocytoma and paraganglioma. In this study, we developed and validated a liquid chromatography–tandem mass spectrometry method for quantifying metanephrine and normetanephrine in human plasma, using solid-phase extraction with a weak cation-exchange mechanism. Validation was performed according to the FDA Bioanalytical Method Validation Guidance and CLSI guideline C62-A. The method showed excellent linearity over concentration ranges of 0.11–13.92 nmol/L for metanephrine and 0.14–26.43 nmol/L for normetanephrine, with correlation coefficients exceeding 0.999. The accuracy, precision, and lower limit of quantification met the acceptance criteria of the study. Matrix effect evaluation revealed a process efficiency of 121% for metanephrine at the lowest concentration, slightly exceeding the acceptable range of 100 ± 15%. This was likely because of matrix-induced ion enhancement or variability in extraction efficiency. However, all other tested concentrations were within the acceptable limits. Overall, this method demonstrated high sensitivity, specificity, and reproducibility, making it suitable for routine clinical applications. Minor deviations at low concentrations do not compromise reliability; however, future optimizations, such as matrix-matched calibration, may further improve performance.