Pilar Andaluz

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.

Ten Novel Mutations in the NR5A1 Gene Cause Disordered Sex Development in 46,XY and Ovarian Insufficiency in 46,XX Individuals

CONTEXT Steroidogenic factor-1 (SF-1/NR5A1) is a nuclear receptor that regulates adrenal and reproductive development and function. NR5A1 mutations have been detected in 46,XY individuals with disorders of sexual development (DSD) but apparently normal adrenal function and in 46,XX women with normal sexual development yet primary ovarian insufficiency (POI). OBJECTIVE A group of 100 46,XY DSD and two POI was studied for NR5A1 mutations and their impact. DESIGN Clinical, biochemical, histological, genetic, and functional characteristics of the patients with NR5A1 mutations are reported. SETTING Patients were referred from different centers in Spain, Switzerland, and Turkey. Histological and genetic studies were performed in Barcelona, Spain. In vitro studies were performed in Bern, Switzerland. PATIENTS A total of 65 Spanish and 35 Turkish patients with 46,XY DSD and two Swiss 46,XX patients with POI were investigated. MAIN OUTCOME Ten novel heterozygote NR5A1 mutations were detected and characterized (five missense, one nonsense, three frameshift mutations, and one duplication). RESULTS The novel NR5A1 mutations were tested in vitro by promoter transactivation assays showing grossly reduced activity for mutations in the DNA binding domain and variably reduced activity for other mutations. Dominant negative effect of the mutations was excluded. We found high variability and thus no apparent genotype-structure-function-phenotype correlation. Histological studies of testes revealed vacuolization of Leydig cells due to fat accumulation. CONCLUSIONS SF-1/NR5A1 mutations are frequently found in 46,XY DSD individuals (9%) and manifest with a broad phenotype. Testes histology is characteristic for fat accumulation and degeneration over time, similar to findings observed in patients with lipoid congenital adrenal hyperplasia (due to StAR mutations). Genotype-structure-function-phenotype correlation remains elusive.

Vascular Endothelial Growth Factor Is Expressed in Human Fetal Growth Cartilage

Angiogenesis is a crucial event in endochondral ossification. Chemoattractants and mitogens for endothelial cells (such as basic fibroblast growth factor [bFGF] and transforming growth factor β [TGF‐β]), which act as local regulators of the process, are synthesized by chondrocytes under several stimuli and in relation to the differentiation stage of the cartilage. Vascular endothelial growth factor (VEGF) is a 44‐kDa protein well known as a potent angiogenic molecule owing to its mitogenic and permeability‐causing properties. In this work, VEGF was located by immunohistochemistry in growth plate cartilage of human fetuses (20–22 weeks old) and its expression was demonstrated by reverse‐transcription polymerase chain reaction (RT‐PCR). Primary culture of human fetal epiphyseal chondrocytes (HFEC) maintained VEGF expression at protein and messenger RNA (mRNA) levels and this expression was stimulated by cartilage‐promoting growth factors incorporated into the culture media (rFGF‐b, rTGF‐β1, and insulin‐like growth factor [rIGF‐I] at 50 ng/ml). The conditioned medium (CM) of HFEC stimulated the proliferation of endothelial cells, and this was partially blocked by anti‐VEGF antibody. These studies showed VEGF production by chondrocytes of the epiphyseal growth cartilage and suggested a role of this factor in cartilage physiology and the angiogenic process.

The exon 3-deleted/full-length Growth Hormone Receptor Polymorphism Does Not Influence the Effect of Puberty or Growth Hormone Therapy on Glucose Homeostasis in Short Non-Growth Hormone-Deficient Small-for-Gestational-Age Children: Results from a Two-Year Controlled Prospective Study

CONTEXT The exon 3-deleted/full-length (d3/fl) GH receptor polymorphism (d3/fl-GHR) has been associated with responsiveness to GH therapy in short small-for-gestational-age (SGA) patients, although consensus is lacking. However, its influence on glucose homeostasis, at baseline or under GH therapy, has not been investigated. OBJECTIVE Our objective was to evaluate whether the d3/fl-GHR genotypes influence insulin sensitivity in short SGA children before or after puberty onset or during GH therapy. DESIGN We conducted a 2-yr prospective, controlled, randomized trial. SETTING Thirty Spanish hospitals participated. Auxological, GH secretion, and glucose homeostasis evaluation was hospital based, whereas molecular analyses and data computation were centralized. PATIENTS Patients included 219 short SGA children [body mass index sd score (SDS) < or = 2.0]; 159 were prepubertal (group 1), and 60 had entered puberty (group 2). INTERVENTION Seventy-eight patients from group 1 were treated with GH (66 microg/kg.d) for 2 yr (group 3). MAIN OUTCOME MEASURES Previous and 2-yr follow-up auxological and biochemical data were recorded, d3/fl-GHR genotypes determined, and data analyzed. RESULTS In groups 1 and 2, fasting glucose, insulin, homeostasis model assessment (HOMA), and quantitative insulin sensitivity check index (QUICKI) were similar in each d3/fl-GHR genotype. Group 2 glucose, insulin, and HOMA were significantly higher and QUICKI lower than in group 1. In group 3 GH-treated patients, height SDS, growth velocity SDS, fasting glucose, insulin, and HOMA significantly increased as did body mass index SDS at the end of the second year, and QUICKI decreased during the first and second years, with no differences among the d3/fl-GHR genotypes. CONCLUSION In short SGA patients, the d3/fl-GHR genotypes do not seem to influence prepubertal or pubertal insulin sensitivity indexes or their changes over 2 yr of GH therapy (66 mug/kg.d).

Clinical, Biochemical and Morphologic Diagnostic Markers in an Infant Male Pseudohermaphrodite Patient with Compound Heterozygous Mutations (G115D/R246W) in SRD5A2 Gene

A patient with male pseudohermaphroditism and clinical diagnosis of partial androgen insensitivity in the neonatal period was studied at pubertal age for a molecular diagnosis. Hormone studies were conducted at baseline and under hCG stimulation for testosterone and dihydrotestosterone determinations at 2 months of age. Gonadectomy was performed at 4 months. At the age of 13 years genital skin fibroblasts were studied for androgen binding and 5α-reductase activity and peripheral blood DNA was available for androgen receptor (AR) and 5α-reductase (SRD5A2) gene analysis. Exons 1–8 of AR gene and exons 1–5 of SRD5A2 gene were sequenced. AR gene coding sequences were normal. SRD5A2 gene analysis revealed two heterozygote mutations (G115D and R246W), with the mother carrying the G115D and the father the R246W mutations. The compound heterozygote mutations in SRD5A2 gene explained an extremely low 5α-reductase enzyme activity in genital skin fibroblasts. Revision of hormonal data from the neonatal period revealed an increased testosterone-to-dihydrotestosterone ratio at the end of an hCG stimulation test, which concurred with the molecular diagnosis. Testis morphology at 4 months of age was normal. Clinical and biochemical differential diagnosis between partial androgen insensitivity syndrome and 5α-reductase enzyme deficiency is difficult in the neonatal period and before puberty. Our results show that in our patient the testosterone-to-dihydrotestosterone ratio would have adequately orientated the diagnosis. The two mutations in SRD5A2 gene have been described in patients of different lineages, though not in combination to date. Testis morphology showed that, during early infancy, the 5α-reductase deficiency may not have affected interstitial or tubular development.

SRD5A2 gene mutations and polymorphisms in Spanish 46,XY patients with a disorder of sex differentiation.

One hundred and forty-six index patients with 46,XY DSD in whom gonads were confirmed as testes were consecutively studied for a molecular diagnosis during the period 2002-2010. AR gene was analysed in all patients as the first candidate gene, yielding a mutation in 42.5% of cases and SRD5A2 gene was analysed as the second candidate gene, resulting in the characterization of 10 different mutations (p.Y91D, p.G115D, p.Q126R, p.R171S, p.Y188CfsX9, p.N193S, p.A207D, p.F219SfsX60, p.R227Q and p.R246W) in nine index patients (6.2% of the total number of 46,XY DSD patients). One of the mutations (p.Y188CfsX9) has never been reported. In addition, we genotyped SRD5A2 gene p.V89L and c.281+15T>C polymorphisms in 46,XY DSD and in 156 normal adult males and found that patients with SRD5A2 mutations or without a known molecular diagnosis presented a higher frequency of homozygous p.L89, homozygous TT and combined CCTT genotypes compared with controls. This result suggests that 46,XY DSD patient phenotypes may be influenced by SRD5A2 polymorphism genotypes. SRD5A2 gene mutations may not be as infrequent as previously considered in 46,XY DSD patients with variable degrees of external genitalia virilization at birth and normal T production and appears to be the second aetiology in our series.

Vitamin D and growth hormone regulate growth hormone/insulin-like growth factor (GH–IGF) axis gene expression in human fetal epiphyseal chondrocytes

OBJECTIVE Cell proliferation and gene expression regulation were studied in human fetal epiphyseal chondrocytes to ascertain the involvement of GH-IGF axis components in human fetal growth regulation by 1,25-dihydroxyvitamin D(3) (VitD) and growth hormone (GH). DESIGN Chondrocytes from primary cultures were plated in serum-free medium for 48 h and incubated for a further 48 h with VitD (10(-11) to 10(-6)M) and/or IGF-I (100 ng/ml) and/or GH (500 ng/ml). We analyzed (3)H-thymidine incorporation into DNA and IGF-I, IGFBP-3, GHR, SOX9, COL2A1, aggrecan and COMP gene expression by real-time quantitative PCR. RESULTS VitD dose-dependently and significantly inhibited (3)H-thymidine incorporation whereas GH had no effect on proliferation and, when combined with VitD, the same inhibition was observed as with VitD alone. IGF-I (100 ng/ml) significantly stimulated proliferation and opposed inhibition by VitD. VitD dose-dependently stimulated IGF-I (11.1+/-19.8 at VitD10(-6)M), IGFBP-3 (2.6+/-0.9), GHR (3.8+/-2.8) and COMP (1.5+/-0.6) expression whereas it inhibited SOX9 (0.7+/-0.2), COL2A1 (0.6+/-0.3) and aggrecan (0.6+/-0.2) expression and had no significant effect on IGF-II. IGF-I stimulated IGF-I, IGFBP-3, SOX9, COL2A1 and aggrecan expression and opposed COL2A1 and aggrecan gene expression inhibition by VitD. GH alone had no effect on gene expression whereas, in the presence of VitD, significantly-increased IGF-I expression stimulation was observed above values obtained with VitD alone (17.5+/-7.4). CONCLUSIONS Our results suggest that VitD regulation of fetal growth cartilage could have consisted of parallel enhancing of cell differentiation and conditioning to a phenotype more sensitive to regulation by other hormones such as GH as shown by increased GHR and IGF-I expression, but not by IGF-II expression which was not regulated.

Familial short stature and intrauterine growth retardation associated with a novel mutation in the IGF-I receptor (IGF1R) gene

IGF‐I is essential for normal human growth and mediates its effects through the IGF1R. IGF1R mutations have been associated with varying degrees of intrauterine and postnatal growth retardation.

STAR splicing mutations cause the severe phenotype of lipoid congenital adrenal hyperplasia: insights from a novel splice mutation and review of reported cases

The steroidogenic acute regulatory protein (StAR) transports cholesterol to the mitochondria for steroidogenesis. Loss of StAR function causes lipoid congenital adrenal hyperplasia (LCAH) which is characterized by impaired synthesis of adrenal and gonadal steroids causing adrenal insufficiency, 46,XY disorder of sex development (DSD) and failure of pubertal development. Partial loss of StAR activity may cause adrenal insufficiency only.

Contribution of human growth hormone-releasing hormone receptor (GHRHR) gene sequence variation to isolated severe growth hormone deficiency (ISGHD) and normal adult height

Molecular causes of isolated severe growth hormone deficiency (ISGHD) in several genes have been established. The aim of this study was to analyse the contribution of growth hormone‐releasing hormone receptor (GHRHR) gene sequence variation to GH deficiency in a series of prepubertal ISGHD patients and to normal adult height.