Novel (60%) and recurrent (40%) androgen receptor gene mutations in a series of 59 patients with a 46,XY disorder of sex development.

BACKGROUND Androgen receptor (AR) gene mutations are the most frequent cause of 46,XY disorders of sex development (DSD) and are associated with a variety of phenotypes, ranging from phenotypic women [complete androgen insensitivity syndrome (CAIS)] to milder degrees of undervirilization (partial form or PAIS) or men with only infertility (mild form or MAIS). OBJECTIVE The aim of the study was to characterize the contribution of the AR gene to the molecular cause of 46,XY DSD in a series of Spanish patients. SETTING We studied a series of 133 index patients with 46,XY DSD in whom gonads were differentiated as testes, with phenotypes including varying degrees of undervirilization, and in whom the AR gene was the first candidate for a molecular analysis. METHODS The AR gene was sequenced (exons 1 to 8 with intronic flanking regions) in all patients and in family members of 61% of AR-mutated gene patients. RESULTS AR gene mutations were found in 59 individuals (44.4% of index patients), of whom 46 (78%) were CAIS and 13 (22%) PAIS. Fifty-seven different mutations were found: 21.0% located in exon 1, 15.8% in exons 2 and 3, 57.9% in exons 4-8, and 5.3% intronic. Twenty-three mutations (40.4%) had been previously described and 34 (59.6%) were novel. CONCLUSIONS AR gene mutation is the most frequent cause of 46,XY DSD, with a clearly higher frequency in the complete phenotype. Mutations spread along the whole coding sequence, including exon 1. This series shows that 60% of mutations detected during the period 2002-2009 were novel.

Population pharmacokinetics of teicoplanin in children.

Teicoplanin is frequently administered to treat Gram-positive infections in pediatric patients. However, not enough is known about the pharmacokinetics (PK) of teicoplanin in children to justify the optimal dosing regimen. The aim of this study was to determine the population PK of teicoplanin in children and evaluate the current dosage regimens. A PK hospital-based study was conducted. Current dosage recommendations were used for children up to 16 years of age. Thirty-nine children were recruited. Serum samples were collected at the first dose interval (1, 3, 6, and 24 h) and at steady state. A standard 2-compartment PK model was developed, followed by structural models that incorporated weight. Weight was allowed to affect clearance (CL) using linear and allometric scaling terms. The linear model best accounted for the observed data and was subsequently chosen for Monte Carlo simulations. The PK parameter medians/means (standard deviation [SD]) were as follows: CL, [0.019/0.023 (0.01)] × weight liters/h/kg of body weight; volume, 2.282/4.138 liters (4.14 liters); first-order rate constant from the central to peripheral compartment (Kcp), 0.474/3.876 h(-1) (8.16 h(-1)); and first-order rate constant from peripheral to central compartment (Kpc), 0.292/3.994 h(-1) (8.93 h(-1)). The percentage of patients with a minimum concentration of drug in serum (Cmin) of <10 mg/liter was 53.85%. The median/mean (SD) total population area under the concentration-time curve (AUC) was 619/527.05 mg · h/liter (166.03 mg · h/liter). Based on Monte Carlo simulations, only 30.04% (median AUC, 507.04 mg · h/liter), 44.88% (494.1 mg · h/liter), and 60.54% (452.03 mg · h/liter) of patients weighing 50, 25, and 10 kg, respectively, attained trough concentrations of >10 mg/liter by day 4 of treatment. The teicoplanin population PK is highly variable in children, with a wider AUC distribution spread than for adults. Therapeutic drug monitoring should be a routine requirement to minimize suboptimal concentrations. (This trial has been registered in the European Clinical Trials Database Registry [EudraCT] under registration number 2012-005738-12.).