Identification of missense mutations in the SRD5A2 gene from patients with steroid 5α‐reductase 2 deficiency

Vilchis,; Méndez,; Lieberman,; Chávez,

doi:10.1046/j.1365-2265.2000.00941.x

Cited by 49 publications

(37 citation statements)

References 22 publications

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“…Nearly 40% of the subjects we studied were homozygous or heterozygous for Pro212 ? Arg Vilchis et al 2000;Chávez et al 2000). The prevalence of alterations at this site in Mexican patients could be the result of a founder gene effect.…”

Section: Discussionmentioning

confidence: 99%

Novel compound heterozygous mutations in the SRD5A2 gene from 46,XY infants with ambiguous external genitalia

Vilchis

Valdez²,

Ramos

et al. 2008

J Hum Genet

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Dihydrotestosterone is crucial for normal development of external genitalia and prostate in the male embryo. Autosomal recessive mutations in the 5a-reductase type 2 (SRD5A2) gene disrupt the synthesis of dihydrotestosterone in the urogenital tract and give rise to genetic males with undervirilized external genitalia that may be femalelike or ambiguous. In this study, three unrelated 46,XY children (0.5, 3, and 8 years old) who presented severe undermasculinization at birth were examined for genetic abnormalities in the SRD5A2 gene. Coding sequence abnormalities were ascertained by exon-specific polymerase chain reaction (PCR), single-stranded conformational polymorphism (SSCP), and sequencing analysis. Functional properties of the mutant alleles were investigated by means of site-directed mutagenesis assays. DNA molecular studies showed that all three patients were compound heterozygotes for SRD5A2 mutations. Patient 1 had a point mutation 547G ? A in exon 3 (G183S) and a novel dinucleotidic mutation 634,635CC ? TG in exon 4 (P212X). This double change results in premature termination signal (TGA) at codon 212, which predicts the expression of a truncated 211-amino acid protein. Patient 2 was the carrier of mutations G115D in exon 3 and S210F in exon 4. Patient 3 had two substitution mutations in exon 1, including a novel G ? C transversion at nucleotide 169 (E57Q) and a G ? A transition at nucleotide 254 (G85D). In transitory transfection assays, the recombinant cDNAs harboring mutations E57Q and G85D showed residual 5a-reductase activity, whereas those with mutations G115D, S210F, and P212X were devoided of activity. In contrast, the G183S substitution affected the catalytic activity of the enzyme by decreasing its affinity for testosterone substrate. We describe six different mutations of the SRD5A2 gene detected in three children with genital ambiguity. These genotypes are consistent with the clinical phenotype of steroid 5a-reductase 2 deficiency. Our data suggest that the combined gene variants (E57Q/G85D, G115D/S210F, and G183S/P212X) result in subfunctional or nonfunctional enzymes, causing masculinization defects in these patients. This further underscores that exon 4 of SRD5A2 may be a site prone to inactivating mutations.

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Section: Discussionmentioning

confidence: 99%

Novel compound heterozygous mutations in the SRD5A2 gene from 46,XY infants with ambiguous external genitalia

Vilchis

Valdez²,

Ramos

et al. 2008

J Hum Genet

View full text Add to dashboard Cite

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“…Single-stranded conformational polymorphism (SSCP) analysis of PCR products was performed according to the method of Orita (1989), using [α-32 P] deoxycytidine triphosphate as described elsewhere (Vilchis et al 2000). Sequencing of the mutant and normal PCR fragments was carried out with the Thermosequenase ([α-33 P] dideoxynucleotide triphosphate) terminator cycle sequencing kit (Amersham, Cleveland, OH, USA), following the manufacturer's recommendations.…”

Section: Methodsmentioning

confidence: 99%

Eight novel mutations of the androgen receptor gene in patients with androgen insensitivity syndrome

et al. 2001

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Androgen insensitivity syndrome (AIS) is an X-linked genetic disorder of male sexual differentiation caused by mutations in the androgen receptor (AR) gene. A reliable genotype-phenotype correlation in these patients does not exist as yet. Here we report the molecular studies performed on eight individuals with AIS. Exon-specific polymerase chain reaction (PCR), single-strand conformation polymorphism, and sequencing analyses, were performed in exons 2 to 8 of the AR gene. In one case, total cellular RNA was extracted from genital skin fibroblasts and reverse transcriptase-PCR was performed. Six different point mutations leading to amino acid substitutions (P682T, Q711E, G743E, F827V, H874R, D879Y), one splicejunction mutation (gAEc at ϩ5, exon 6/intron 6), and a missense mutation without amino acid substitution (S888S) were identified. All mutations, including a de novo mutation, were previously undescribed on the steroid binding domain. Of the eight mutations identified, four led to a complete female phenotype (codons 743, 827, 874 and the donor splice site ϩ5), two were detected in phenotypic females with partial virilization (codons 682 and 711), and two were present in phenotypic male subjects with undervirilized external genitalia, thus indicating that all of these sites determine AR functional activity.

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“…However, in many instances, this method has failed as a good predictor and various other approaches have been proposed [22,39,41,45,49], urinary steroid profiling (UPS) and gene mutation analysis being two alternatives. Chan et al suggested that UPS results can be misinterpreted; thus, molecular [25,39,40] p.G115D/p.G115D 5 2.60 0.55 [22,39,41,42] analysis was considered the most effective diagnostic method also taking into account the small size of the gene makes the diagnostic procedure easier [50].…”

Section: Diagnosismentioning

confidence: 99%

5-α-Reductase type 2 deficiency: is there a genotype-phenotype correlation? A review

et al. 2018

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5-α-Reductase type 2 enzyme catalyzes the conversion of testosterone into dihydrotestosterone, a potent androgen responsible for male sexual development during the fetal period and later during puberty. Its deficiency causes an autosomal recessive disorder of sex development characterized by a wide range of under-virilization of external genitalia in patients with a 46,XY karyotype. Mutations in the SRD5A2 gene cause 5-α-Reductase deficiency; although it is an infrequent disorder, it has been reported worldwide, with mutational heterogeneity. Furthermore, it has been proposed that there is no genotype-phenotype correlation, even in patients carrying the same mutation. The aim of this review was to perform an extensive search in various databases and to select those articles with a comprehensive genotype and phenotype description of the patients, classifying their phenotypes using the external masculinization score (EMS). Thus, it was possible to objectively compare the eventual genotypephenotype correlation between them. The analysis showed that for most of the studied mutations no correlation can be established, although the specific location of the mutation in the protein has an effect on the severity of the phenotype. Nevertheless, even in patients carrying the same homozygous mutation, a variable phenotype was observed, suggesting that additional genetic factors might be influencing it. Due to the clinical variability of the disorder, an accurate diagnosis and adequate medical management might be difficult to carry out, as is highlighted in the review.

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Identification of missense mutations in the SRD5A2 gene from patients with steroid 5α‐reductase 2 deficiency

Cited by 49 publications

References 22 publications

Novel compound heterozygous mutations in the SRD5A2 gene from 46,XY infants with ambiguous external genitalia

Novel compound heterozygous mutations in the SRD5A2 gene from 46,XY infants with ambiguous external genitalia

Eight novel mutations of the androgen receptor gene in patients with androgen insensitivity syndrome

5-α-Reductase type 2 deficiency: is there a genotype-phenotype correlation? A review

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