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.

5 alpha-reductase-2 gene mutations in the Dominican Republic.

Male pseudohermaphroditism due to 5 alpha-reductase deficiency was clinically and biochemically described in a large Dominican kindred of 23 families with 38 affected subjects in 1974. Recently, the 5 alpha-reductase-2 gene defect in the large Dominican kindred was found to be due to a single base substitution of thymidine (TGG) for cytosine (CGG) on exon 5 of the 5 alpha-reductase-2 gene, causing a tryptophan replacement of arginine at amino acid 246 (R246W) of the enzyme. In the present report, affected subjects from four additional Dominican families were studied to determine whether they carried the same 5 alpha-reductase-2 gene defect as the large kindred, suggesting a common ancestry for the gene defect within this small country. Using single strand conformational polymorphism and DNA sequencing, two other mutations of the 5 alpha-reductase-2 gene were found in affected subjects from two of the four families. A point mutation on exon 2 of the 5 alpha-reductase-2 gene, in which substitution of adenine (GAC) for guanine (GGC) caused an aspartic acid replacement of glycine at amino acid 115 (G115D), was demonstrated in one of these families, and a substitution of adenine (AGT) for guanine (GGT) on exon 3 causing a serine replacement for glycine at amino acid 183 (G183S) was detected in the other family. Affected subjects from the two remaining families demonstrated the same exon 5 mutation of the 5 alpha-reductase-2 gene as previously detected in the large Dominican kindred. The phenotypic and biochemical characteristics of the male pseudohermaphrodites were similar regardless of the genetic defect, except that one affected subject (C-VI-2) with the same exon 5 mutation as the large Dominican kindred had much more facial and body hair. Thus, the identification of multiple mutations in the 5 alpha-reductase-2 gene in male pseudohermaphrodites from the Dominican Republic demonstrates a lack of common ancestry, as had been previously postulated.

Male pseudohermaphroditism due to primary 5 alpha-reductase deficiency: variation in gender identity reversal in seven Mexican patients from five different pedigrees.

In the present study, we describe the clinical, endocrinological, psychosexual and biochemical features of 7 Mexican male pseudohermaphrodites with primary 5 alpha-reductase deficiency in whom heterogeneity in the pattern of gender identity change at puberty was observed. The patients belonged to 5 different pedigrees from diverse locations in Mexico. Six of them were admitted to the Hospital during or after puberty. The one prepubertal subject was the sibling of a previously studied patient. Basal serum gonadotropins were determined by double antibody radioimmunoassay. Basal and choriogonadotropin (CG)-stimulated concentrations of androstenedione (A), testosterone (T) and dihydrotestosterone (DHT) were determined by radioimmunoassay after extraction and separation by celite chromatography. Urinary aetiocholanolone, androsterone and C19 and C21 5 beta/5 alpha metabolite ratios were analyzed by capillary gas chromatography. Enzyme activity and androgen receptors were studied in fibroblasts cultured from genital skin. Psychological assessment was performed using the Bender-Gestalt Wechsler Adult Intelligence Scale, the Rorschach Ink Blot and the Thematic Apperception Tests. All 7 patients were unambiguously reared as females; three spontaneously changed their gender identity and role from female to male after puberty, another one changed during psychotherapy at the end of puberty. Two patients (one prepubertal and the other pubertal) have been under therapy during 1.5 years, but due to familial and social factors a female gender has prevailed. The remaining patient consulted at age 15 because of virilization; her female gender identity did not change after more than one year of treatment and due to the fact she was depressed and had suicidal tendencies, the penis and testes were removed.(ABSTRACT TRUNCATED AT 250 WORDS)

The prevalence of 5 alpha-reductase deficiency in children with ambiguous genitalia in the Dominican Republic.

During a 10-year period 65 children and adolescents with ambiguous genitalia from the Dominican Republic, not known through kindred studies of 5 alpha-reductase deficiency, were evaluated. Plasma androgen determinations were performed before and/or after Leydig cell stimulation of the testes with human chorionic gonadotropin. Of the children there were 24 female pseudohermaphrodites, 21 of whom had 21-hydroxylase deficiency, 1 true hermaphrodite and 40 (62 per cent) male pseudohermaphrodites. One child had a human chorionic gonadotropin response suggestive of 17-20 desmolase deficiency, and on further evaluation he also had partial deficiencies of the enzymes 21-hydroxylase and 17 alpha-hydroxylase. Five subjects had a female phenotype and subnormal androgen responses to human chorionic gonadotropin. In 5 of 33 male pseudohermaphrodites with a normal testosterone response to human chorionic gonadotropin 5 alpha-reductase deficiency was suspected by elevated plasma testosterone/dihydrotestosterone ratios before and/or after human chorionic gonadotropin stimulation. The diagnosis of 5 alpha-reductase deficiency was confirmed by elevated 5 beta/5 alpha urinary C19 and C21 steroid metabolite ratios. One subject with 5 alpha-reductase deficiency was traced to the original Dominican kindred of 38 affected subjects. Pedigree analysis of another proband revealed 3 additional affected relatives. Four subjects with a normal testosterone response to human chorionic gonadotropin had XO/XY gonadal dysgenesis. There were 25 male pseudohermaphrodites with normal plasma testosterone and dihydrotestosterone responses to human chorionic gonadotropin, who were not diagnosed by this methodology. This study reveals that 5 alpha-reductase deficiency occurs with a frequency of 13 per cent as a cause of male pseudohermaphroditism in the Dominican Republic with approximately the same frequency as XO/XY gonadal dysgenesis. Unlike female pseudohermaphrodites, the majority of male subjects with pseudohermaphroditism remain unclassified by these techniques.

Androgens and the evolution of male-gender identity among male pseudohermaphrodites with 5alpha-reductase deficiency.

To determine the contribution of androgens to the formation of male-gender identity, we studied male pseudohermaphrodites who had decreased dihydrotestosterone production due to 5 alpha-reductase deficiency. These subjects were born with female-appearing external genitalia and were raised as girls. They have plasma testosterone levels in the high normal range, show an excellent response to testosterone and are unique models for evaluating the effect of testosterone, as compared with a female upbringing, in determining gender identity. Eighteen of 38 affected subjects were unambiguously raised as girls, yet during or after puberty, 17 of 18 changed to a male-gender identity and 16 of 18 to a male-gender role. Thus, exposure of the brain to normal levels of testosterone in utero, neonatally and at puberty appears to contribute substantially to the formation of male-gender identity. These subjects demonstrate that in the absence of sociocultural factors that could interrupt the natural sequence of events, the effect of testosterone predominates, over-riding the effect of rearing as girls.

Steroid 5alpha-reductase deficiency in man: an inherited form of male pseudohermaphroditism.

In male pseudohermaphrodites born with ambiguity of the external genitalia but with marked virilization at puberty, biochemical evaluation reveals a marked decrease in plasma dihydrotestosterone secondary to a decrease in steroid 5alpha-reductase activity. In utero the decrease in dihydrotestosterone results in incomplete masculinization of the external genitalia. Inheritance is autosomal recessive.