Male pseudohermaphroditism caused by mutations of the human androgen receptor.
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Disorders of Sex Development↗
Biomedical subjects
J E Griffin
Publications and source records attributed to J E Griffin.
Laser-assisted endoscopic forehead lift.
The periorbital area is one of the most expressive areas of the face, and there are many techniques available that can be used to alter the position of the eyebrows. Traditional surgical browlift techniques use coronal, midforehead, and direct approaches. This article discusses one of the most recent innovations in forehead lifting, the laser-assisted endoscopic forehead lift. A review of the literature describes the numerous available surgical techniques used to change the position of the eyebrow. The surgical technique for the laser-assisted endoscopic forehead lift is then presented in detail and illustrated with the results of two cases.
Female↗
Inactivation of the luteinizing hormone/chorionic gonadotropin receptor by an insertional mutation in Leydig cell hypoplasia.
We previously identified a nonsense mutation (Cys545Stop) in the paternal human LH/CG receptor (hLHR) allele in a family with two 46,XY children afflicted with Leydig cell hypoplasia. This mutation abolished the signal transduction capability of the affected hLHR. We have now examined all coding exons and the transcript of both alleles of the hLHR gene of the affected children. A 33-bp in-frame insertion was found in the maternal hLHR allele. This insertion occurred between nucleotide 54 and 55 and might be the result of a partial gene duplication. Genomic DNA-PCR showed that this defective maternal hLHR allele was inherited by the two affected children. However, examination of the inheritance of the 935-A/G polymorphism of the hLHR by genomic- and RT-PCR indicated that the maternal hLHR allele was not expressed in cultured fibroblasts of the patients. The effect of the in-frame insertion on the biological activity of the hLHR was examined by expressing the mutated hLHR construct, generated by site-directed mutagenesis, in HEK 293 cells. The expression of the mRNA for the mutant hLHR in HEK 293 cells was not affected. Response of cells expressing the mutated hLHR to hCG stimulation was impaired as demonstrated by reduced intracellular cAMP biosynthesis. This change in signal transduction was the result of a profound reduction in hormone binding at the cell surface due to altered expression and processing of the mutated receptor. We conclude that Leydig cell hypoplasia in this family is the result of compound heterozygous loss-of-function mutations of the hLHR gene.
Alleles↗
Posttraumatic scar revision: a review and case presentation.
Scar revision is a well-established procedure, but the achievement of satisfying long-term results may present a challenge. An appropriate initial management of wounds is of importance, since it has a role in determining the degree of revision required postoperatively. In addition to the conventional treatment and maturation of the scar tissue, a combination of procedures are now available which may alter the appearance of the final scar. Scar revision, followed by wound care that consists of silastic sheeting, steroid injection, and laser skin resurfacing with carbon dioxide laser (CO2), may be used as adjuncts to achieve camouflage of facial scars. Two case reports are presented to document the procedure, followed by treatment evaluation and protocol.
Adult↗
The use of the C-Arm in reduction of isolated zygomatic arch fractures: a technical overview.
Isolated zygomatic arch fractures account for approximately 10% of all zygoma fractures. Numerous techniques have been described to reduce these fractures using a variety of approaches. Successful reductions are often difficult to evaluate clinically because of the great amount of swelling that often accompanies these fractures. Postoperative radiographs are often the only way to assess the adequacy of the reduction. This article describes a technique that uses the C-Arm to quickly and accurately evaluate the reduction intraoperatively so that appropriate corrections can be made. A case report of a patient who suffered multiple orthopedic injuries and a w-shaped depressed fracture of the left zygomatic arch is presented. The C-Arm can obviate the need for intraoperative radiographs that, due to technician and film processing delays, add significantly to operative time.
Adult↗
Objective evaluation of the eyelids and eyebrows after blepharoplasty.
PURPOSE: Surgery of the upper and lower eyelids and eyebrows is primarily designed to enhance the esthetic appearance and provide functional visual field benefits. Paramount to successful surgical results is a carefully executed examination and treatment plan. The preoperative and postoperative evaluation of these individuals has been primarily subjective. This article describes a method for the quantification of periorbital relationships that is of use in the preoperative planning and postoperative evaluation of patients undergoing esthetic surgery of the eyelids and eyebrows. PATIENTS AND METHODS: The photographic records of 15 female patients who had undergone bilateral upper eyelid surgery were examined. None of the patients underwent lower eyelid or eyebrow surgery. Preoperative and postoperative frontal photographs were projected to a standard size, and measurements were made in a standardized fashion. For the comparison of intrapatient and interpatient relationships, objective anthropometric proportions rather than average measurements were used. Therefore, standard periorbital relationships were recorded and expressed as anthropometric ratios. Measurements were recorded for 30 eyes. The preoperative and postoperative relationships were measured and reported as mean values with standard deviation. The relationships studied were: 1) Upper lid height to orbit height, 2) Lower lid height to orbit height, 3) Lid sulcus height to orbit height, 4) Lid sulcus height to upper lid height, 5) Upper iris coverage to iris height, 6) Lower iris coverage to iris height, 7) Orbit height to middle facial height, 8) Medial brow to orbit height, 9) Lateral brow to orbit height, and 10) Eye fissure height to orbit height. Brow heights were measured vertically from a line connecting exocanthion and endocanthion. RESULTS: The postoperative changes in these patients showed the following: Upper lid height, eye fissure height, and brow position were not significantly affected by upper lid blepharoplasty surgery. The sulcus lid height was doubled postoperatively, and upper iris coverage was decreased slightly postoperatively. CONCLUSIONS: The results of the study indicate that the proposed methodology is appropriate for the objective evaluation of periorbital relationships pertinent to esthetic periorbital surgery. Its use is suggested as a diagnostic aid in preoperative planning and postsurgical evaluation.
Adult↗
Molecular genetics and pathophysiology of 17 beta-hydroxysteroid dehydrogenase 3 deficiency.
Autosomal recessive mutations in the 17 beta-hydroxysteroid dehydrogenase 3 gene impair the formation of testosterone in the fetal testis and give rise to genetic males with female external genitalia. Such individuals are usually raised as females, but virilize at the time of expected puberty as the result of increases in serum testosterone. Here we describe mutations in 12 additional subjects/families with this disorder. The 14 mutations characterized to date include 10 missense mutations, 3 splice junction abnormalities, and 1 small deletion that results in a frame shift. Three of these mutations have occurred in more than 1 family. Complementary DNAs incorporating 9 of the 10 missense mutations have been constructed and expressed in reporter cells; 8 of the 9 missense mutations cause almost complete loss of enzymatic activity. In 2 subjects with loss of function, missense mutations testosterone levels in testicular venous blood were very low. Considered together, these findings strongly suggest that the common mechanism for testosterone formation in postpubertal subjects with this disorder is the conversion of circulating androstenedione to testosterone by one or more of the unaffected 17 beta-hydroxysteroid dehydrogenase isoenzymes.
17-Hydroxysteroid Dehydrogenases↗
A nonsense mutation of the human luteinizing hormone receptor gene in Leydig cell hypoplasia.
Leydig cell hypoplasia (LCH) is a form of male pseudohermaphroditism in which Leydig cell differentiation and testosterone production are impaired. This report describes the first case of a nonsense mutation (A1635C) in exon 11 of the human luteinizing hormone receptor (hLHR) gene in two sisters with LCH. This mutation causes loss of function of the receptor by introducing a stop codon at residue 545 in transmembrane helix 5 of the hLHR. Surface expression of the truncated hLHR (hLHR-t545) in human embryonic kidney cells stably transfected with cDNA encoding hLHR-t545 was diminished compared to the wild-type hLHR and hCG-induced cAMP accumulation was impaired. These results establish that single base mutations in exon 11 of the hLHR gene can produce inactivation as well as activation of the hLHR. Furthermore, they demonstrate that functional domains between transmembrane helix 5 and the C-terminal cytoplasmic tail of the hLHR are required for normal cell surface expression of the receptor and signal transduction.
Base Sequence↗
Mutations of the androgen receptor coding sequence are infrequent in patients with isolated hypospadias.
Androgen receptor defects can cause severe hypospadias. To examine the possibility that androgen receptor defects are a common cause of such deficiencies, we have determined the coding sequence of the androgen receptor gene in nine patients with severe hypospadias. The analysis of the androgen receptor coding sequence predicts a normal amino acid sequence for the androgen receptor of eight of the nine patients, indicating that the observed defects in virilization are infrequently caused by mutations of the open-reading frame of the androgen receptor. These findings demonstrate the importance of family history and endocrine studies in identifying patients likely to harbor coding sequence mutations in the androgen receptor gene, and they serve to focus attention on other genes that may influence androgen action in this group of patients.
Base Sequence↗
Amino acid substitutions in the hormone-binding domain of the human androgen receptor alter the stability of the hormone receptor complex.
We have investigated the basis of androgen resistance in seven unrelated individuals with complete testicular feminization or Reifenstein syndrome caused by single amino acid substitutions in the hormone-binding domain of the androgen receptor. Monolayer-binding assays of cultured genital skin fibroblasts demonstrated absent ligand binding, qualitative abnormalities of androgen binding, or a decreased amount of qualitatively normal receptor. The consequences of these mutations were examined by introducing the mutations by site-directed mutagenesis into the androgen receptor cDNA sequence and expressing the mutant cDNAs in mammalian cells. The effects of the amino acid substitutions on the binding of different androgens and on the capacity of the ligand-bound receptors to activate a reporter gene were investigated. Substantial differences were found in the responses of the mutant androgen receptors to incubation with testosterone, 5 alpha-dihydrotestosterone, and mibolerone. In several instances, increased doses of hormone or increased frequency of hormone addition to the incubation medium resulted in normal or near normal activation of a reporter gene by cells expressing the mutant androgen receptors. These studies suggest that the stability of the hormone receptor complex is a major determinant of receptor function in vivo.
Androgen-Insensitivity Syndrome↗
Leydig cell neoplasia in a patient with Reifenstein syndrome.
We present the rare coincidence of a Leydig cell tumor in both testicles of a patient with partial androgen insensitivity syndrome (PAIS). The clinical picture with perineoscrotal hypospadia, micropenis, gynecomastia and delayed puberty and the serum hormone levels with elevated concentrations of testosterone, luteinising hormone (LH) and follicle-stimulating hormone were entirely consistent with PAIS. Ultimately, the diagnosis was confirmed by determination of genital skin fibroblast androgen receptor binding capacity for 5 beta-dihydrotestosterone, which demonstrated a qualitatively abnormal androgen receptor. At 44 years of age, a nodule in the left testis led to orchidectomy. At that time, the right testis was inconspicuous sonographically. But 3 years later the right testis developed nodules and was removed. Review of testicular histology revealed the presence of Leydig cell hyperplasia (LCH), multifocal nodular hyperplasia and Leydig cell neoplasia (LCN) in both testes. Many micronodules of Leydig cells in transition from hyperplasia to neoplasia were also identified. The simultaneous development of histologically identical nodes of LCN independently from each other and a different sites of both tests indicates the presence of a tumorigenic factor acting on the Leydig cells. Furthermore, the observation of multiple foci of cells in all stages of transition from hyperplasia to neoplasia demonstrates the persistent process of transformation. We speculate, that in this patient the grossly elevated LH levels present over 30 years have enhanced, if not provoked, the formation of LCN. In addition, the defective androgen receptor might have prevented suppressive effects of androgens on the Leydig cells.
Disorders of Sex Development↗
Complete testicular feminization caused by an amino-terminal truncation of the androgen receptor with downstream initiation.
We have characterized the molecular defect causing androgen resistance in two 46,XY siblings with complete testicular feminization. Although binding studies in genital skin fibroblasts showed a reduced Bmax, an increased dissociation rate of ligand, and an 8S peak of dihydrotestosterone binding on sucrose density gradient centrifugation, no immunoreactive androgen receptor (AR) was detected in immunoblots using anti-NH2-terminal antibodies, suggesting an abnormal amino terminus. Sequence analysis of the AR gene revealed a point mutation CAG-->TAG (Gln-->Stop) at nucleotide 340. In vitro mutagenesis studies suggest the synthesis of the mutant AR is initiated downstream of the termination codon at reduced levels and that each molecule is functionally impaired. These results define a novel mechanism causing androgen resistance: the combination of decreased amount and functional impairment of AR caused by an abnormality within the amino terminus of the receptor. These findings suggest that domains important to the in vivo function of the receptor reside within the amino terminus and that disruption of these domains can occur with only subtle effects on receptor binding. Identification of this mutation made it possible to identify the mutant allele within the family and to ascertain antenatally that it was not present in a 46,XY fetal sibling of the proband at 9 wk gestation.
Alleles↗
Steroid 5 alpha-reductase 2 deficiency.
In the 20 yr since it was established that impairment of dihydrotestosterone formation is the cause of a rare form of human intersex, a wealth of information has accumulated about the genetics, endocrinology, and variable phenotypic manifestations, culminating in the cloning of cDNAs encoding two 5 alpha-reductase genes and documentation that mutations in the steroid 5 alpha-reductase 2 gene are the cause of 5 alpha-reductase deficiency. Perplexing and difficult problems remain unresolved, e.g. whether the variability in manifestations is due to variable expressions of steroid 5 alpha-reductase 1 or to effects of testosterone itself. It is also imperative to establish whether defects in steroid 5 alpha-reductase 2, perhaps in the heterozygous state, are responsible for a portion of cases of sporadic hypospadias, to determine whether 5 alpha-reductase plays a role in progesterone action in women, and to elucidate the relation between androgen action and gender role behavior.
3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Genetic basis of endocrine disease. 4. The spectrum of mutations in the androgen receptor gene that causes androgen resistance.
Mutations in the androgen receptor gene cause phenotypic abnormalities of male sexual development that range from a female phenotype (complete testicular feminization) to that of undervirilized or infertile men. Using the tools of molecular biology, we have analyzed androgen receptor gene mutations in 31 unrelated subjects with androgen resistance syndromes. Most of the defects are due to nucleotide changes that cause premature termination codons or single amino acid substitutions within the open reading frame encoding the androgen receptor, and the majority of these substitutions are localized in three regions of the androgen receptor: the DNA-binding domain and two segments of the androgen-binding domain. Less frequently, partial or complete gene deletions have been identified. Functional studies and immunoblot assays of the androgen receptors in patients with androgen resistance indicate that in most cases the phenotypic abnormalities are the result of impairment of receptor function or decreases in receptor abundance or both.
Androgen-Insensitivity Syndrome↗
Androgen resistance--the clinical and molecular spectrum.
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3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Molecular basis of androgen resistance.
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Androgens↗
Molecular genetics of steroid 5 alpha-reductase 2 deficiency.
Two isozymes of steroid 5 alpha-reductase encoded by separate loci catalyze the conversion of testosterone to dihydrotestosterone. Inherited defects in the type 2 isozyme lead to male pseudohermaphroditism in which affected males have a normal internal urogenital tract but external genitalia resembling those of a female. The 5 alpha-reductase type 2 gene (gene symbol SRD5A2) was cloned and shown to contain five exons and four introns. The gene was localized to chromosome 2 band p23 by somatic cell hybrid mapping and chromosomal in situ hybridization. Molecular analysis of the SRD5A2 gene resulted in the identification of 18 mutations in 11 homozygotes, 6 compound heterozygotes, and 4 inferred compound heterozygotes from 23 families with 5 alpha-reductase deficiency. 6 apparent recurrent mutations were detected in 19 different ethnic backgrounds. In two patients, the catalytic efficiency of the mutant enzymes correlated with the severity of the disease. The high proportion of compound heterozygotes suggests that the carrier frequency of mutations in the 5 alpha-reductase type 2 gene may be higher than previously thought.
3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Mutations in the ligand-binding domain of the androgen receptor gene cluster in two regions of the gene.
We have analyzed the nucleotide sequence of the androgen receptor from 22 unrelated subjects with substitution mutations of the hormone-binding domain. Eleven had the phenotype of complete testicular feminization, four had incomplete testicular feminization, and seven had Reifenstein syndrome. The underlying functional defect in cultured skin fibroblasts included individuals with absent, qualitative, or quantitative defects in ligand binding. 19 of the 21 substitution mutations (90%) cluster in two regions that account for approximately 35% of the hormone-binding domain, namely, between amino acids 726 and 772 and between amino acids 826 and 864. The fact that one of these regions is homologous to a region of the human thyroid hormone receptor (hTR-beta) which is a known cluster site for mutations that cause thyroid hormone resistance implies that this localization of mutations is not a coincidence. These regions of the androgen receptor may be of particular importance for the formation and function of the hormone-receptor complex.
Amino Acid Sequence↗