Cytochrome P450 (CYP) 3A enzymes, the most important phase 1 drug-metabolizing enzymes, are responsible for 50% of the metabolism of clinically used drugs. CYP3A activity varies widely among individuals, which can affect the probability of adverse drug reactions and drug-drug interactions mediated by the induction or inhibition of the enzyme. Hence, it is important to be able to predict CYP3A activity in individuals to reduce the incidence of unexpected drug responses. To specifically and quickly measure CYP3A activity, we developed method based on gas chromatography interfaced with triple-quadrupole mass spectrometry for the quantification of cortisol, cortisone, 6β-hydroxycortisol, and 6β-hydroxycortisone simultaneously in urine and 4β-hydroxycholesterol in plasma. The results were calculated based on charcoal-stripped steroid-free urine and plasma control samples. The accuracy and precision were 93.18% to 110.0% and 1.96% to 5.34%, respectively. This method was then applied to measure endogenous steroids from urine and plasma samples of healthy Korean males and females. The calibration curves of all analytes showed good linearity with a correlation coefficient (r2) that ranged from 0.9953 to 0.9999. Therefore, this validated method can be used to measure endogenous biomarkers to predict CYP3A activity and might be applicable in the prediction of CYP3A-mediated drug interactions of new drug candidates.

BACKGROUND: To validate the clinical application of chromosomal microarray analysis (CMA) as a first-tier clinical diagnostic test and to determine the impact of CMA results on patient clinical management, we conducted a multicenter prospective study in Korean patients diagnosed as having developmental delay/intellectual disability (DD/ID), autism spectrum disorders (ASD), and multiple congenital anomalies (MCA). METHODS: We performed both CMA and G-banding cytogenetics as the first-tier tests in 617 patients. To determine whether the CMA results directly influenced treatment recommendations, the referring clinicians were asked to complete a 39-item questionnaire for each patient separately after receiving the CMA results. RESULTS: A total of 122 patients (19.8%) had abnormal CMA results, with either pathogenic variants (N=65) or variants of possible significance (VPS, N=57). Thirty-five well-known diseases were detected: 16p11.2 microdeletion syndrome was the most common, followed by Prader-Willi syndrome, 15q11-q13 duplication, Down syndrome, and Duchenne muscular dystrophy. Variants of unknown significance (VUS) were discovered in 51 patients (8.3%). VUS of genes putatively associated with developmental disorders were found in five patients: IMMP2L deletion, PTCH1 duplication, and ATRNL1 deletion. CMA results influenced clinical management, such as imaging studies, specialist referral, and laboratory testing in 71.4% of patients overall, and in 86.0%, 83.3%, 75.0%, and 67.3% of patients with VPS, pathogenic variants, VUS, and benign variants, respectively. CONCLUSIONS: Clinical application of CMA as a first-tier test improves diagnostic yields and the quality of clinical management in patients with DD/ID, ASD, and MCA.
Autism Spectrum Disorder ; Autistic Disorder ; Cytogenetics ; Diagnostic Tests, Routine ; Down Syndrome ; Humans ; Intellectual Disability ; Korea ; Microarray Analysis ; Muscular Dystrophy, Duchenne ; Prader-Willi Syndrome ; Prospective Studies ; Referral and Consultation ; Specialization

Most cases of congenital hyperthyroidism are autoimmune forms caused by maternal thyroid stimulating antibodies. Nonautoimmune forms of congenital hyperthyroidism caused by activating mutations of the thyrotropin receptor (TSHR) gene are rare. A woman gave birth to a boy during an emergency cesarean section at 33 weeks of gestation due to fetal tachycardia. On the 24th day of life, thyroid function tests were performed due to persistent tachycardia, and hyperthyroidism was confirmed. Auto-antibodies to TSHR, thyroid peroxidase, and thyroglobulin were not found. The patient was treated with propylthiouracil and propranolol, but hyperthyroidism was not well controlled. At 3 months of age, the patient had craniosynostosis and hydrocephalus, and underwent a ventriculoperitoneal shunt operation. Direct sequencing of the TSHR gene showed a heterozygous mutation of c.1899C>A (p.Asp633Glu) in exon 10. No mutations were discovered in any of the parents in a familial genetic study. We have reported a case of sporadic nonautoimmune congenital hyperthyroidism, by a missense mutation of the TSHR gene, for the first time in South Korea.
Cesarean Section ; Craniosynostoses ; Emergencies ; Exons ; Female ; Germ-Line Mutation ; Humans ; Hydrocephalus ; Hyperthyroidism* ; Immunoglobulins, Thyroid-Stimulating ; Iodide Peroxidase ; Korea ; Male ; Mutation, Missense ; Parents ; Parturition ; Pregnancy ; Propranolol ; Propylthiouracil ; Receptors, Thyrotropin ; Tachycardia ; Thyroglobulin ; Thyroid Function Tests ; Ventriculoperitoneal Shunt

BACKGROUND: We describe the genetic profiles of Korean patients with glucose-6-phosphate dehydrogenase (G6PD) deficiencies and the effects of G6PD mutations on protein stability and enzyme activity on the basis of in silico analysis. METHODS: In parallel with a genetic analysis, the pathogenicity of G6PD mutations detected in Korean patients was predicted in silico. The simulated effects of G6PD mutations were compared to the WHO classes based on G6PD enzyme activity. Four previously reported mutations and three newly diagnosed patients with missense mutations were estimated. RESULTS: One novel mutation (p.Cys385Gly, labeled G6PD Kangnam) and two known mutations [p.Ile220Met (G6PD São Paulo) and p.Glu416Lys (G6PD Tokyo)] were identified in this study. G6PD mutations identified in Koreans were also found in Brazil (G6PD São Paulo), Poland (G6PD Seoul), United States of America (G6PD Riley), Mexico (G6PD Guadalajara), and Japan (G6PD Tokyo). Several mutations occurred at the same nucleotide, but resulted in different amino acid residue changes in different ethnic populations (p.Ile380 variant, G6PD Calvo Mackenna; p.Cys385 variants, Tomah, Madrid, Lynwood; p.Arg387 variant, Beverly Hills; p.Pro396 variant, Bari; and p.Pro396Ala in India). On the basis of the in silico analysis, Class I or II mutations were predicted to be highly deleterious, and the effects of one Class IV mutation were equivocal. CONCLUSIONS: The genetic profiles of Korean individuals with G6PD mutations indicated that the same mutations may have arisen by independent mutational events, and were not derived from shared ancestral mutations. The in silico analysis provided insight into the role of G6PD mutations in enzyme function and stability.
Asian Continental Ancestry Group/*genetics ; Child ; Child, Preschool ; DNA/chemical synthesis/genetics/metabolism ; Exons ; Glucosephosphate Dehydrogenase/chemistry/*genetics/metabolism ; Glucosephosphate Dehydrogenase Deficiency/*genetics/pathology ; Humans ; Male ; Mutation, Missense ; Polymorphism, Genetic ; Protein Structure, Tertiary ; Republic of Korea ; Sequence Analysis, DNA

BACKGROUND: We evaluated a sensitive and quantitative method utilizing fragment analysis of the fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD), simultaneously measuring mutant allele burden and length, and verified the analytical performance. METHODS: The number and allelic burden of FLT3-ITD mutations was determined by fragment analysis. Serial mixtures of mutant and wild-type plasmid DNA were used to calculate the limit of detection of fragment analysis, conventional PCR, and Sanger sequencing. Specificity was evaluated using DNA samples derived from 50 normal donors. Results of fragment analysis were compared to those of conventional PCR, using 481 AML specimens. RESULTS: Defined mixtures were consistently and accurately identified by fragment analysis at a 5% relative concentration of mutant to wild-type, and at 10% and 20% ratios by conventional PCR and direct sequencing, respectively. No false positivity was identified. Among 481 AML specimens, 40.1% (193/481) had FLT3-ITD mutations. The mutant allele burden (1.7-94.1%; median, 28.2%) and repeated length of the mutation (14-153 bp; median, 49 bp) were variable. The concordance rate between fragment analysis and conventional PCR was 97.7% (470/481). Fragment analysis was more sensitive than conventional PCR and detected 11 additional cases: seven had mutations below 10%, three cases represented conventional PCR failure, and one case showed false negativity because of short ITD length (14 bp). CONCLUSIONS: The new fragment analysis method proved to be sensitive and reliable for the detection and monitoring of FLT3-ITD in patients with AML. This could be used to simultaneously assess ITD mutant allele burden and length.
Alleles ; DNA ; Humans ; Leukemia, Myeloid, Acute ; Limit of Detection ; Methods ; Plasmids ; Polymerase Chain Reaction* ; Sensitivity and Specificity ; Tissue Donors ; Vascular Endothelial Growth Factor Receptor-1

Birt-Hogg-Dubé syndrome (BHDS) is a rare disease with autosomal dominant inheritance that manifests through skin tumors, pulmonary cystic lesions, and renal tumors. A mutation of FLCN located on chromosome 17p11.2, which encodes a tumor-suppressor protein (folliculin), is responsible for the development of BHDS. We report the case of a patient presenting with spontaneous pneumothorax, in whom a familial genetic study revealed a novel nonsense mutation: p.(Arg379*) in FLCN.
Birt-Hogg-Dube Syndrome* ; Codon, Nonsense ; Estrone* ; Humans ; Pneumothorax* ; Rare Diseases ; Skin ; Thoracic Surgery, Video-Assisted ; Thoracoscopy ; Wills

Birt-Hogg-Dubé syndrome (BHDS) is a rare disease with autosomal dominant inheritance that manifests through skin tumors, pulmonary cystic lesions, and renal tumors. A mutation of FLCN located on chromosome 17p11.2, which encodes a tumor-suppressor protein (folliculin), is responsible for the development of BHDS. We report the case of a patient presenting with spontaneous pneumothorax, in whom a familial genetic study revealed a novel nonsense mutation: p.(Arg379*) in FLCN.
Birt-Hogg-Dube Syndrome* ; Codon, Nonsense ; Estrone* ; Humans ; Pneumothorax* ; Rare Diseases ; Skin ; Thoracic Surgery, Video-Assisted ; Thoracoscopy ; Wills

Pseudohypoparathyroidism (PHP) is a rare disorder caused by genetic and epigenetic aberrations in the GNAS complex locus resulting in impaired expression of stimulatory G protein (Gsα). PHP type Ib (PHP-Ib) is characterized by hypocalcemia and hyperphosphatemia due to renal resistance to the parathyroid hormone, and is distinguished from PHP-Ia by the absence of osteodystrophic features. An 11-yr-old boy presented with poor oral intake and cramping lower limb pain after physical activity. Laboratory studies revealed hypocalcemia, hyperphosphatemia, and increased parathyroid hormone levels. The GNAS complex locus was evaluated using the methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) assay. Gain of methylation in the NESP55 domain and loss of methylation in the antisense (AS) transcript, XL, and A/B domains in the maternal allele were observed. Consequently, we present a case of PHP-Ib diagnosed using MS-MLPA.
Alleles ; Epigenomics ; GTP-Binding Proteins ; Humans ; Hyperphosphatemia ; Hypocalcemia ; Lower Extremity ; Male ; Methylation* ; Motor Activity ; Multiplex Polymerase Chain Reaction ; Muscle Cramp ; Parathyroid Hormone ; Pseudohypoparathyroidism*

No abstract available.
Humans ; Kansas*

No abstract available.
Humans ; Kansas*