Ultrasonography (US) is of value in the evaluation and characterization of breast masses in children. Most masses represent either normal breast tissue, cysts, or fibroadenomas. Premature thelarche may be unilateral, and normal breast tissue is found at US. Cysts are commonly retroareolar; when they become infected, they appear sonographically as a complex mass. Fibroadenoma is the most frequent breast tumor in adolescent girls, and it is usually solitary, homogeneous, and hypoechoic. Malignant breast lesions are very rare in children; most are due to metastatic disease secondary to rhabdomyosarcoma, leukemia, lymphoma, and neuroblastoma, and their US appearance is nonspecific. Gynecomastia in boys can be mimicked by general obesity and pectoral hypertrophy; US is helpful in the diagnosis, especially when gynecomastia is asymmetric. Most breast lesions in children and adolescents are benign, and surgery should be avoided to prevent later deformity. US is the ideal imaging modality to evaluate breast lesions and may be used to guide a fine-needle aspiration biopsy. Color Doppler US evaluation is helpful; cysts are avascular, fibroadenomas may be avascular or hypovascular, and abscesses show peripheral increased flow. Bloody nipple discharge is more common in prepubertal patients, may occur in infants, and may be secondary to mammary ductal ectasia. Discharge commonly resolves spontaneously, and findings at US are frequently normal.

TART in prepubertal males with classic CAH could be found during childhood. We also report differences in markers of gonadal function in a subgroup of patients, especially in those with inadequate control.

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) and inserts three amino acids (L141, W142, and A143). In transactivation assays, the recreated mutant VDR was 1000-fold less active than the wildtype (WT) VDR. In glutathione S-transferase (GST) pull-down assays, the mutant VDR bound GST-retinoid X receptor (RXR) weakly in the absence of 1,25(OH) 2 D 3 ; however, the binding did not increase with increasing concentrations of ligand. The mutant VDR did not bind to GST-vitamin D receptor interacting protein (DRIP) 205 at concentrations up to 1 M 1,25(OH) 2 D 3 . We also examined effects of the three individual mutations on VDR transactivation. Only the insertion of A143 into the WT VDR disrupted VDR transactivation to the same extent observed with the natural mutation. Conclusion: We describe a novel insertion/substitution mutation in helix H1 of the VDR ligand-binding domain (LBD) that abolishes ligand binding and result in the syndrome of HVDRR. This is the first time an insertion/ substitution has been found as the defect-causing HVDRR.

Analysis by PCR was more sensitive in detecting Y chromosome sequences than conventional karyotype. The presence of Y material was not associated with virilization. We confirmed the association of Y fragments and gonadoblastoma at an early age.

We propose a molecular explanation for the reduced activity exhibited by the MC2R alanine 126 by serine mutant.

Mutations in the Fibroblast Growth FactorReceptor 3 gene (FGFR3) in Chilean patients with idiopathic short stature, hypochondroplasia and achondroplasia Background: Achondroplasia and hypochondroplasia are skeletal dysplasias of autosomal dominant inheritance that represent different degrees of severity of the same pathological entity. Both dysplasias are caused by mutations in the Fibroblast Growth Factor Receptor 3 (FGFR3) gene. In achondroplasia more than 95% of the cases studied to date carry the same mutation (G380R). Hypochondroplasia represents a greater clinical and genetic heterogeneity, possibly being confused with "idiopathic short stature". The N540K mutation has been detected in 50-70% of cases of hypochondroplasia and mutations at the 650 locus in approximately 2.8%. Aim: To assess the frequency of N540K and G380R mutations, and changes at the 650 locus in Chilean patients with idiopathic disproportionate short stature, hypochondroplasia and achondroplasia. Patients and Methods: We studied 21 patients referred for idiopathic short stature, 5 with clinically suspected hypochondroplasia and 4 with achondroplasia. The G1138A, G1138C (G380R), and C1620, C1620A (N540K) mutations and the nucleotide changes at the 650 locus were studied using PCR and restriction analysis of genomic DNA. Results: Three out of five hypochondroplasia patients were heterozygous for the N540K mutation. All of the 4 patients with achondroplasia presented the G1138A mutation. None of these mutations were found in patients with idiopathic short stature. Conclusion: Chilean patients with hypochondroplasia and achondroplasia have the same mutations described in other ethnic groups. The identification of mutations in 3 out of 5 patients with hypochondroplasia shows that this analysis is a useful tool for its diagnostic confirmation. In short stature the molecular study should only be indicated in those cases presenting other clinical and/or radiological features of hypochondroplasia (Rev Méd Chile 2003; 131: 1405-10). (

Steroid 21-hydroxylase deficiency (21OHD) compromises about 95% of all cases of congenital adrenal hyperplasia. We have characterized the disease-causing mutations in the steroid 21-hydroxylase genes of 19 Chilean patients (12 females and 7 males) with the simple virilizing (SV) form of 21OHD and compared them with other SV-populations. Using allele-specific polymerase chain reaction, we identified lesions in 28 chromosomes out of 38 tested (73.7%). The most frequent finding was the mutation I173N=12/38 (31.6%) similar as described in Caucasian, Asian and other Hispanic populations, where this mutation represents around 20-40% of the genetic defects in the CYP21B gene. The mutation V282L=4/38 (10.5%) and deletion (Del) or large gene conversion (LGC)=3/38 (7.9%) were also frequently detected. Only 2 alleles carried the mutation I2 splice (5.3%), this frequency is lower than that reported in Caucasian or in Mexican populations. We did not find alleles with the mutations R357W, Cluster E6, P31L and P454S in these patients. The complete genotype was determined in 11/19 patients (58%) and one allele in 6/19 patients (31.6%). In summary, about 30% of the Chilean population with SV 21OHD presented the missense mutation I173N as described in other populations. The frequency of the other lesions showed differences even between populations with similar genetic background.