Knowledge of appropriate foods and beverages needed for weight loss and diet of patients in an Obesity Clinic.

BACKGROUND/OBJECTIVE: Knowledge does not automatically translate into behaviour change. This study examined the relationship between knowledge of appropriate foods and beverages needed for weight loss and the diet of patients seeking weight management. SUBJECTS/METHODS: A cross-sectional study of 104 consecutive first-time patients (55 women and 49 men) seeking weight management, with a mean age of 37.3 ± 11.8 years and a BMI of 44.9 ± 9.4 kg/m(2), was carried out; 67.3% of these patients had a BMI of 40 kg/m(2) or greater. Patients were told to design a detailed weight-loss diet that they would recommend to a person with the same characteristics (recommended diet or RD) as themselves and asked whether the RD was similar to their own. Consumed diet (CD) was assessed by a different dietitian through a 24-h diet recall. Estimated energy requirement (EER), energy content of RD and CD and number of fruit, vegetable, cereal and sweetened-beverage portions were calculated. Statistical differences were assessed through the Pearson's correlation and the Wilcoxon's rank-sum tests. RESULTS: RD and CD were 1104 ± 243 and 1976 ± 708 kcal for women and 1254 ± 287 and 2743 ± 1244 kcal for men, with statistical differences for both genders (P<0.001). Energy content of the RD was lower than the EER in men and women (P<0.001); CD was lower than the EER in women (P=0.033). Number of fruit/vegetable portions was lower in CD than in the RD in women (P<0.001), whereas cereal and sweetened-beverage portions were higher in CD than in the RD in both genders (P<0.001). RD was not followed by 46.1% of the patients. CONCLUSIONS: Patients with obesity seeking care have knowledge of the appropriate dietary strategies needed for weight loss, but do not translate it into practice. Treatment approaches should include tools that help patients to implement their nutrition knowledge.

Full-length SRY protein is essential for DNA binding.

SRY directs testicular development. It has been suggested that the only high-mobility group (HMG) box of the SRY is important for the function of this protein; however, other studies have suggested that the N- and C-terminal regions are also involved in this process. Herein, we analysed and compared in vitro the DNA-binding activity of the full-length SRY and three mutants (HMG box alone, N-terminal less and C-terminal less SRY proteins). DNA-binding capability was analysed by mobility shift assays, optical density and dissociation constant by using pure non-fusion SRY proteins. The structure of the full-length SRY was carried out using a protein molecular model. The HMG box SRY alone and C-terminal less SRY proteins had a statistically diminished DNA binding in comparison with the full-length SRY. In contrast, the affinity for DNA of the N-terminal less SRY was relatively similar to the full-length SRY. Likewise, three-dimensional structure of the full-length SRY suggested that some residues of the C-terminal region of the SRY interact with DNA. We demonstrate the importance that full-length SRY has, particularly the C-terminal region of the protein, in DNA binding in vitro. Likewise, the affinity of the HMG box alone is clearly reduced when compared with the full-length SRY.

CRH-stimulation of cyclic adenosine 5'-monophosphate pathway is partially inhibited by the coexpression of CRH-R1 and CRH-R2alpha.

Corticotropin-releasing hormone (CRH) is one of the major proteins responsible for brain stress regulation. Two well-known receptors have been described: type 1 and type 2alpha, both members of the receptor superfamily of G protein-coupled receptors (GPCR). We investigated receptor regulation when both CRH receptor subtypes are coexpressed in the same mammalian cell line. When both types of receptors are coexpressed, cAMP second messenger production is partially inhibited compared to when receptors are expressed separately. However, neither binding kinetics nor internalization rates are modified by coexpression of these receptors. To our knowledge this is the first demonstration of receptor interaction that results in the modification of CRH-mediated signal transduction pathway. Because CRH-R1 and CRH-R2alpha have overlapping mRNA expression patterns in the brain, these receptors may be coexpressed in neurons, suggesting that receptor interaction may play an important role in the effect evoked by CRH, contributing to the complexity of differential coupling of the CRH receptors in different endocrine and stress behavior responses.

Regulation of follicle-stimulating and luteinizing hormone receptor signaling by.

Follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) belong to the super-family of G protein-coupled receptors (GPCR); GPCRs are negatively regulated by RGS ("regulators of G protein signaling") proteins. In this study we evaluated the effects of RGS3 and RGS10 on FSHR and LHR ligand binding and effector coupling. FSHR and LHR ligand binding were unchanged in the presence of RGS3 or RGS10. However, signaling by FSHR and LHR was diminished by RGS3 but not by RGS10. This constitutes the first demonstration of an interaction between RGS proteins and LH and FSH signaling pathways and identifies a mechanism for negative regulation of RGS3 on FSHR and LHR signaling.

Basal and gonadotropin-releasing hormone-releasable serum follicle-stimulating hormone charge isoform distribution and in vitro biological-to-immunological ratio in male puberty.

Follicle-stimulating hormone is synthesized and secreted as a mixture of heterogeneous isoforms that differ from each other in carbohydrate structure, biological potency, and plasma half-life. The relative abundance of the FSH isoforms will depend on the endocrine status of the donor at the time of sample collection. In the present study, we attempted to define the impact of the changing endocrine milieu characteristic of male puberty on the charge heterogeneity and plasma half-life of the serum FSH isoforms released under endogenous and exogenous GnRH drives, and examined whether such a varying hormone milieu modifies the capability of the circulating hormone to trigger intracellular signal transduction at the human FSH receptor level. Forty healthy male subjects at Tanner stages (Ts) 1 to 5 were sampled at 10 min intervals for 10 h. Serum from successive samples collected across 2-4 h intervals containing FSH released under basal, low-dose (10 microg), and high-dose (90 microg) exogenous GnRH-stimulated conditions was subjected to preparative chromatofocusing and tested for bioactivity employing a homologous cell in vitro bioassay system. Deconvolution analysis was applied to estimate the apparent endogenous FSH plasma half-life in samples obtained after administration of low-dose exogenous GnRH. Under all conditions studied, serum FSH charge isoforms were distributed along a pH range of 7.0 to less than 3.0. Comparisons across the different Tanner stages revealed a significant and selective increase in the ratio of FSH isoforms with elution pH values <4.50 relative to those with values >/=4.50 at Ts-2. At Ts-3, this ratio returned to that present at Ts-1, to decline thereafter during the ensuing pubertal stages. Serum bioactive FSH concentrations progressively increased (from 3.72 +/- 1.3 to 16.2 +/- 5.3 IU/L) throughout puberty, and in all conditions bioactive FSH concentrations exceeded those detected by a specific radioimmunoassay. The biological to immunological (B:I) FSH ratio at baseline was significantly (p < 0.05) lower at Ts-1 and Ts-2 (1.33 +/- 0.30 and 1.62 +/- 0.34, respectively) than at more advanced stages of pubertal development (2.28 +/- 0.20, 2.96 +/- 0.38, and 2.77 +/- 0.63 at Ts-3-, 4-, and -5, respectively) Similar differences were detected in samples containing FSH molecules released after low- and high-dose GnRH administration. The apparent endogenous FSH half-life of the deconvolved GnRH-induced FSH pulses was similar in the five study groups. These results demonstrate that the transition from infancy to sexual maturity in men is accompanied by qualitative changes in the circulating FSH isoform mixture. Although the changes in FSH glycosylation occurring throughout puberty are not of sufficient magnitude to alter the survival of the gonadotropin in circulation, they allow preferential secretion of bioactive FSH. The enrichment of the circulating mix of FSH isoforms with highly bioactive variants throughout spontaneous puberty may potentially favor the development of spermatogenesis and acquisition of reproductive competence.

Polymorphic changes in the KAL1 gene: not all of them should be classified as polymorphisms.

The KAL1 gene has a closely related nonfunctional pseudogene on the Y chromosome; a high degree of X-Y sequence similarity is observed. Some individuals present a T to C substitution at position 1833 (exon 12). Because this nucleotide differs in the X (thymine) and in the Y (cytosine) chromosome, we investigated if this was truly a polymorphism, or if in some cases the Y sequence had been amplified. The complete sequence of exon 12 of KAL1 was analyzed in 11 Kallmann Syndrome (KS) males, in 50 normal males, in 50 normal females, and in 16 patients with Ullrich-Turner Syndrome (UTS). Nucleotide 1833 was found in a heterozygous or a homozygous state in KS, normal males and normal females; UTS patients were always homozygous. Of the 61 males, 17 were heterozygous, while 11 were TT and 33 were CC. With these observations we can not assure whether these patients present a "real" polymorphism. Besides, all males were heterozygous in nucleotides 1678, 1694, 1699, 1708 and 1825, whilst females were homozygous; and in these positions, KAL1 also differs from its pseudogene. These results indicate that we are identifying the X and the Y nucleotide and these variants are not polymorphisms. Sequence variations may be pseudogene products rather than true polymorphisms, so we should always determine if the position where the variation is located differs between KAL1 and its pseudogene, because it has been suggested that the presence of various polymorphisms in affected individuals could be the cause of KS.

46,XX sex reversal.

In humans, sexual differentiation is directed by SRY, a master regulatory gene located at the Y chromosome. This gene initiates the male pathway or represses the female pathway by regulating the transcription of downstream genes; however, the precise mechanisms by which SRY acts are largely unknown. Moreover, several genes have recently been implicated in the development of the bipotential gonad even before SRY is expressed. In some individuals, the normal process of sexual differentiation is altered and a sex reversal disorder is observed. These subjects present the chromosomes of one sex but the physical attributes of the other. Over the past years, considerable progress has been achieved in the molecular characterization of these disorders by using a combination of strategies including cell biology, animal models, and by studying patients with these pathologic entities.

Changes in the biological:immunological ratio of basal and GnRH-releasable FSH during the follicular, pre-ovulatory and luteal phases of the human menstrual cycle.

BACKGROUND: Significant changes in charge isoform distribution of serum FSH occur throughout the human menstrual cycle. In the present study, we analysed the impact of the changing endocrine milieu characteristic of the menstrual cycle on the capability of basal and gonadotrophin-releasing hormone (GnRH)-releasable FSH to trigger intracellular signal transduction via the human FSH receptor. METHODS: Seven normal women underwent blood sampling every 10 min for 10 h during the early follicular phase (FP), pre-ovulatory phase (PO) and mid- to late luteal phase (LP) of the menstrual cycle. Serum from successive samples collected across 2 h intervals containing FSH released under baseline and exogenous GnRH-stimulated conditions was tested for bioactivity employing a homologous in-vitro assay. RESULTS: The biological to immunological (B:I) ratio of basal and GnRH-releasable FSH was significantly (P < 0.05 ) higher at LP (range, 0.83 +/- 0.07 to 1.35 +/- 0.30) than during the FP (0.43 +/- 0.02 to 0.65 +/- 0.04) and PO (0.49 +/- 0.05 to 0.62 +/- 0.06). In all phases, the B:I FSH ratio in baseline samples was similar to those exhibited by samples collected after 10 and 90 microg GnRH administration. CONCLUSIONS: The selective increase in the capability of the admixture of FSH isoforms circulating during the LP to activate the FSH receptor, apparently represents an additional mechanism through which the anterior pituitary may regulate the maturation of those follicles destined to ovulate during the coming cycle.

Clinical expression and SRY gene analysis in XY subjects lacking gonadal tissue.

In several syndromes genetic males lack gonadal tissue. A range of phenotypes are seen, which varies from complete female external genitalia to anorchic subjects with sexual infantilism. Differences in phenotypic expression depend on the stage at which testes degenerated during intrauterine development. Although most cases of these syndromes are sporadic, several instances of familial recurrence suggest a genetic origin. To help elucidate the source, we performed molecular analysis of the complete SRY gene open reading frame in two subjects with true agonadism and in two with anorchia. Our results add to previous findings indicating that molecular defects in SRY are not readily identified as a cause of these syndromes.

Is there any physiological role for gonadotrophin oligosaccharide heterogeneity in humans? I. Gondatrophins are synthesized and released in multiple molecular forms. A matter of fact.

Carbohydrates attached to the protein core of all glycoprotein hormones play an essential role in the function of the molecule, influencing a number of intracellular and extracellular processes. As with other members of the glycoprotein hormone family, pituitary gonadotrophins are not produced as single or unique molecules but rather as arrays of isoforms that differ from each other mainly in the structure of their oligosaccharide attachments. In both experimental animals and in humans, the abundance of the different isoforms varies depending on the endocrine status of the donor present at the time of collection of the tissue or sample. Conditions characterized by an oestrogen-enriched hormonal milieu (eg. the preovulatory phase of the menstrual cycle) promote the formation and secretion of variants with relatively low sialic acid and/or sulphate content, whereas physiological deficiency of this sex steroid (as in the postmenopause) favours the production of highly sialylated, long-lived gonadotrophin variants. When tested individually, less sialylated isoforms exhibit higher receptor-binding and in-vitro biological activity but shorter plasma half-life than their more sialylated counterparts. Both the hormonal regulation and the functional differences among the naturally occurring isoforms strongly suggest that gonadotrophin heterogeneity represents a distinctly different mechanism through which the pituitary gland may regulate the intensity and duration of the gonadotrophic stimulus. Nevertheless, whereas the existence of the alternatively glycosylated variants of gonadotrophins in both the pituitary and in serum is currently without doubt, the physiological role of this phenomenon is still a controversial issue and a matter of debate.

No evidence of mutations in the follicle-stimulating hormone receptor gene in Mexican women with 46,XX pure gonadal dysgenesis.

In the ovary FSH is necessary for normal follicular development, binding to its receptor (FSHR) that pertains to the superfamily of G-protein coupled receptors. In the FSHR gene, which consists of 10 exons, an homozygous mutation was reported in six Finnish families with gonadal dysgenesis; whereas two isolated French patients exhibited compound heterozygous mutations. Several groups, however, have searched for FSHR mutations, although in most cases the gene has been studied partially, not finding any genetic abnormalities in German, English, North American or Brazilian women. We performed direct sequencing of all 10 exons of the FSHR gene in seven sporadic patients and two sisters with 46,XX pure gonadal dysgenesis, to investigate the cause of their disorder. No heterozygous or homozygous mutant alleles were present in any of the patients. Although the number of patients evaluated was small, considering all the other previous reports, it seems that except in the Finnish population, the proportion of women with mutations in the encoding region of this gene is very low. Other possibilities for the presence of 46,XX gonadal dysgenesis, such as defects in the regulatory regions of the FSHR gene promoter, in the untranslated regions of exons 1 and 10, and within introns, or the existence of other genes likely to be important for normal ovarian function on the X chromosome or on autosomes, should be considered. In contrast with other studies, we did not find polymorphisms of the FSHR gene, indicating that apparently in Mexicans this gene is not highly polymorphic.

A preponderance of circulating basic isoforms is associated with decreased plasma half-life and biological to immunological ratio of gonadotropin-releasing hormone-releasable luteinizing hormone in obese men.

Hormonal abnormalities of the reproductive axis have been described in obesity. In men, extreme obesity is associated with low serum testosterone (T) and high estrogen [estrone and estradiol (E(2))] levels. As changes in the sex steroid milieu may profoundly affect the carbohydrate heterogeneity and thus some of the biological and physicochemical properties of the LH molecule, we analyzed the relative distribution of LH isoforms circulating under baseline conditions (endogenous GnRH drive) as well as the forms discharged by exogenous GnRH stimulation from putative acutely releasable and reserve pituitary pools in overweight men. Secondarily, we determined the impact of the changes in LH terminal glycosylation on the in vitro bioactivity and endogenous half-life of the gonadotropin. Seven obese subjects with body mass indexes ranging from 35.7-45.5 kg/m(2) and seven normal men with body mass indexes from 22.5-24.2 kg/m(2) underwent blood sampling at 10-min intervals for a total of 10 h before and after the iv administration of 10 and 90 microg GnRH. Basally released and exogenous GnRH-stimulated serum LH isoforms were separated by preparative chromatofocusing and identified by RIA of eluent fractions. Serum pools of successive samples collected across 2-h intervals (five serum pools per subject) containing LH released under baseline and exogenous GnRH-stimulated conditions were tested for bioactivity employing a homologous in vitro bioassay. Mean serum T and E(2) levels were significantly lower and higher, respectively, in the obese men than in the control group [serum T, 13.5 +/- 2.4 vs. 19.4 +/- 1.4 nmol/L (mean +/- SEM; P: = 0.01); serum E(2), 0.184 +/- 0.01 vs. 0.153 +/- 0.01 nmol/L (P: < 0.05)]. Mean baseline serum LH levels were similar in obese subjects and normal controls (13.3 +/- 1.3 and 12.2 +/- 1.2 IU/L). Although multiple parameter deconvolution of the exogenous GnRH-induced LH pulses revealed that the magnitude of the pituitary response in terms of secretory burst mass, secretory amplitude, and half-duration of the LH pulses was similar in obese and control subjects, the apparent endogenous half-life of LH was significantly (P: < 0.05) shorter in the obese group (98 +/- 11 min) than in the normal controls (132 +/- 10 min). Under all conditions studied, the relative abundance of basic isoforms (those with pH >/=7.0) was significantly (P: < 0.05) increased in the obese subjects compared with the controls (percentages of LH immunoactivity recovered at pH >/=7.0: obese subjects, 34-57%; normal controls, 22-46%). The biological to immunological ratio of LH released in baseline and low dose (10 microg) GnRH-stimulated conditions were similar in obese subjects and normal controls, whereas LH released by obese subjects in response to the high (90 microg) GnRH dose exhibited significantly lower ratios than those detected in normal individuals (0.62 +/- 0.07 and 0.45 +/- 0.09 vs. 1.01 +/- 0.10 and 0.81 +/- 0.09 for LH released within 10-120 min and 130-240 min after GnRH administration in obese and controls, respectively; P: < 0.05). Collectively, these results indicate that the altered sex steroid hormone milieu characteristic of extreme obesity provokes a selective increase in the release of less acidic LH isoforms, which may potentially modify the intensity and duration of the blood LH signal delivered to the gonad. Altered glycosylation of LH may therefore represent an additional mechanism modulating the hypogonadal state prevailing in morbid obesity.

Scant XYqh- testicular cells with normal SRY was enough to differentiate bilateral testes in a 45,X/46,XYqh- patient.

OBJECTIVE: It has been established that in 45,X/46,XY individuals predominance of XY or XO gonadal cells determines gonadal differentiation. However, in some cases there is no concordance between the predominance of XY cells and testis differentiation. Here we describe the SRY findings in a patient bearing a 45,X/46,XYqh- karyotype. STUDY DESIGN: The patient presented two small testes (one with spermatogenesis), a male phenotype, and a predominant 45,X karyotype in leukocytes and gonadal cells. PCRs of SRY, ZFY and Yqh were performed on DNA from leukocytes and from left gonadal tissue. SRY-PCR products were purified and sequenced. RESULTS: A normal SRY sequence was found in both tissues. CONCLUSIONS: Despite the predominance of 45,X cells in gonads, some patients in whom SRY is normal can develop testes, probably due to the presence of alternative mechanisms involved in testicular differentiation; however, further gonadal development could be impaired.

Evidence for genetic heterogeneity in male pseudohermaphroditism due to Leydig cell hypoplasia.

Leydig cell aplasia or hypoplasia is a rare form of male pseudohermaphroditism resulting from inadequate fetal testicular Leydig cell differentiation. Affected individuals presented a wide phenotypic spectrum, ranging from complete female external genitalia to males with micropenis. Recessive mutations in the LH receptor gene have been identified as responsible for the condition. The majority of these mutations are point mutations and have been located in exon 11 of the gene. In this study, we report the molecular characterization of the LH receptor gene in three siblings with Leydig cell hypoplasia. After sequencing the 11 exons of the gene, no deleterious mutations were detected in any patient. However, we identified a previously described polymorphism in exon 11. In patients 1 and 3 DNA sequencing revealed a C to T substitution at nucleotide 1065; both patients were homozygous GAT/GAT at codon 355. In contrast, patient 2 was homozygous GAC/GAC, whereas the father and one unaffected sister were heterozygous GAC/GAT at this polymorphic site. These results exclude that Leydig cell hypoplasia in this family is due to a mutation in the LH receptor gene and provide evidence that defects in other loci may also result in failure of Leydig cell differentiation, demonstrating, for the first time, that Leydig cell hypoplasia is a genetically heterogeneous condition.

[Genetic heterogeneity and phenotypic variability in 46,XY sex reversal]. / Heterogeneidad genética y variabilidad fenotípica en la reversión sexual 46,XY.

The discordance between the chromosomic and the gonadal-phenotypic sex is known as sex reversal (XX males and XY females). We review the XY pure gonadal dysgenesis characterized by female phenotype, primary amenorrhea and absence of secondary sexual development. Bilateral streak gonads are always present in the complete form of this syndrome, while variable degrees of virilization are found in the partial forms, depending on the severity of the testicular damage. A plausible explanation for this pathology are SRY mutations that interfere with the testicular differentiation. However, only 10-15% of the patients with the complete form show SRY mutations, particularly in the HMG box. The remaining cases are probably due to mutations in different autosomal or X-linked genes which are also involved in the sex differentiation cascade. Recently, it has been shown that mutations in several genes responsible of well known genetic entities as WT1, SOX9, DSS and SF1, result in sex reversal. These findings reveal the genetic heterogeneity and clinical variability of XY sex reversal and provide the basis establishing a hierarchy of genes and their participation in the sex determination pathway.

A recurrent missense mutation in the KAL gene in patients with X-linked Kallmann's syndrome.

Kallmann's syndrome (KS) is defined by the association of hypogonadotropic hypogonadism and anosmia or hyposmia. Segregation analysis in familial cases has demonstrated diverse inheritance patterns, suggesting the existence of several genes regulating GnRH secretion. Genetic defects have been demonstrated in the KAL gene, located on the Xp22.3 region, explaining the X-linked form of the disease. We report molecular findings regarding the KAL gene in 12 unrelated males with X-linked KS. PCR of the 14 exons of the KAL gene was performed on genomic DNA. PCR products of all exons were purified and sequenced. Genetic defects in the KAL gene were found in 7 patients. One exhibits a deletion from exon 3 to exon 5. Six individuals present a previously unidentified missense mutation in exon 11, consisting of a G to A substitution at codon 514 (GAA to AAA). In the remaining 5 individuals, no mutations were observed. We also found three different polymorphic changes. The first one, in exon 2, had not been reported previously. The other two were located at exons 11 and 12. The deletion described, comprises only part (exon 5) of the coding region of the first fibronectin type III-like repeat of the KAL protein. The rest of the deletion comprises part of the conserved cysteine-rich N-terminal region that corresponds to the whey acidic protein motif. The same missense mutation was found in 6 of the 12 patients, indicating the possibility that it derived from a common ancestor or suggesting the presence of a hot spot in this region of the gene.

Frequency of Y chromosomal material in Mexican patients with Ullrich-Turner syndrome.

Cytogenetic studies have shown that 40-60% of patients with Ullrich-Turner syndrome (UTS) are 45,X, whereas the rest have structural aberrations of the X chromosome or mosaicism with a second cell line containing a structurally normal or abnormal X or Y chromosome. However, molecular analysis has demonstrated a higher proportion of mosaicism, and studies in different populations have shown an extremely variable frequency of Y mosaicism of 0-61%. We used Southern blot analysis and polymerase chain reaction (PCR) to detect the presence of Ycen, ZFY, SRY, and Yqh in 50 Mexican patients with UTS and different karyotypes to determine the origin of marker chromosomes and the presence of Y sequences. Our results indicated the origin of the marker chromosome in 1 patient and detected the presence of Y sequences in 4 45,X patients. Taken together, we found a 12% incidence of Y sequences in individuals with UTS. The amount of Y-derived material was variable, making the correlation between phenotype and molecular data difficult. Only 1 patient had a gonadoblastoma. We discuss the presence of Y chromosomes or Y sequences in patients with UTS and compare our frequency with that previously reported.

Two SRY-negative XX male brothers without genital ambiguity.

We report a Mexican family in which two sibs were identified as "classic" XX males without genital ambiguities. Molecular studies revealed that both patients were negative for several Y sequences, including SRY. A review of familial cases disclosed that this is the first family where a complete male phenotype was observed in Y-negative XX male non-twin brothers. These data suggest that an inherited loss-of-function mutation, in a gene participating in the sex-determining cascade, can induce normal male sexual differentiation in the absence of SRY.

Codon 89 polymorphism of the human 5alpha-steroid reductase type 2 gene.

The existence of a genetic polymorphism within the coding region of the human 5alpha-steroid reductase type 2 (5alpha-SR2) gene is reported in a Mexican population. Genotypic variation was assessed in 100 unrelated, healthy volunteers (50 males; 50 females), using single-stranded conformational polymorphism and direct sequencing analysis. Examination of exon 1 DNAs disclosed the presence of sequences encoding for valine (GTA) or leucine (CTA) at codon 89 of the gene. Of the subjects screened, 45% were homozygous for GTA (89Val), 50% had a heterozygous pattern GTA/CTA (89Val/89Leu) and the remaining 5% were homozygous for CTA (89Leu). These data support the view that the G/C condition at codon 89 of the 5alpha-SR2 gene represents a silent polymorphism which does not alter phenotypical development in the human.

Mutations of the 5 alpha-reductase type 2 gene in eight Mexican patients from six different pedigrees with 5 alpha-reductase-2 deficiency.

BACKGROUND AND OBJECTIVE: Male pseudohermaphroditism due to 5 alpha-reductase deficiency was originally described in 1974. Recently, 5 alpha-reductase Type 2 gene defects have been found generally to be due to point mutations within the 5 exons of the 5 alpha-reductase-2 gene. In this report, we describe the molecular study of patients with 5 alpha-reductase deficiency. DESIGN: Previously diagnosed patients with 5 alpha-reductase deficiency were sampled in order to perform molecular studies. PATIENTS: Eight 5 alpha-reductase deficient individuals from 6 unrelated families. MEASUREMENTS: Single-strand conformational polymorphism and DNA sequencing were performed after polymerase chain reaction amplification of each of the 5 exons of the gene. RESULTS: Five different missense mutations were found. In 4 patients a cytosine to guanine substitution was observed at codon 212 in exon 4. Two siblings presented a cytosine to adenine substitution at codon 207 in exon 4. Another patient exhibited a guanine to adenine substitution at codon 34 in exon 1, whilst one individual presented 2 mutations: a guanine to adenine substitution at codon 115 in exon 2 and a guanine to adenine substitution at codon 203 in exon 4 (previously undescribed mutation). CONCLUSIONS: The presence of the same mutation in 4 patients from 3 families indicates the increased prevalence of this mutation in a particular ethnic group, suggesting a common ancestry for the gene defect in these patients. The existence of hot spots is supported by the mutations in codons 34 and 207 which have also been found in other ethnic groups. Interestingly, the patient who presented 2 different mutations, one of them previously undescribed, was reared as a male and exhibited a more masculine phenotype. Further studies in patients with this and other mutations will be needed to verify genotype-phenotype correlation.