scholarly journals Predicting Phenotype in Steroid 21-Hydroxylase Deficiency? Comprehensive Genotyping in 155 Unrelated, Well Defined Patients from Southern Germany

2000 ◽  
Vol 85 (3) ◽  
pp. 1059-1065 ◽  
Author(s):  
Nils Krone ◽  
Andreas Braun ◽  
Adelbert Anton Roscher ◽  
Dietrich Knorr ◽  
Hans Peter Schwarz
Keyword(s):  
Splice Site ◽  
Splice Site Mutation ◽  
Compound Heterozygous ◽  
Site Mutation ◽  
Hydroxylase Deficiency ◽  
Salt Wasting ◽  
Severe Mutation ◽  
Heterozygous Form ◽  
21 Hydroxylase Deficiency ◽  
Intron 2

Abstract Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders. CAH is most often caused by deficiency of steroid 21-hydroxylase. The frequency of CYP21-inactivating mutations and the genotype-phenotype relationship were characterized in 155 well defined unrelated CAH patients. We were able to elucidate 306 of 310 disease-causing alleles (diagnostic sensitivity, 98.7%). The most frequent mutation was the intron 2 splice site mutation (30.3%), followed by gene deletions (20.3%), the I172N mutation (19.7%) and large gene conversions (7.1%). Five point mutations were detected that have not been described in other CAH cohorts. Genotypes were categorized in 4 mutation groups (null, A, B, and C) according to their predicted functional consequences and compared to the clinical phenotype. The positive predictive value for null mutations (ppvnull) was 100%, as all patients with these mutations had a salt-wasting phenotype. In mutation group A (intron 2 splice site mutation in homozygous or heterozygous form with a null mutation), the ppvA to manifest with salt-wasting CAH was 90%. In group B predicted to result in simple virilizing CAH (I172N in homozygous or compound heterozygous form with a more severe mutation), ppvB was 74%. In group C (P30L, V281L, P453S in homozygous or compound heterozygous form with a more severe mutation), ppvC was 64.7% to exhibit the nonclassical form of CAH, but 90% when excluding the P30L mutation. Thus, in general, a good genotype-phenotype relationship is shown in patients with either the severest or the mildest mutations. A considerable degree of divergence is observed within mutation groups of intermediate severity. As yet undefined factors modifying 21-hydroxylase gene expression and steroid hormone action are likely to account for these differences in phenotypic expression.

High frequency of splice site mutation in 21-hydroxylase deficiency children

2014 ◽  
Vol 38 (5) ◽  
pp. 505-511 ◽  
Author(s):  
S. Sharaf ◽  
M. Hafez ◽  
D. ElAbd ◽  
A. Ismail ◽  
G. Thabet ◽  
...  
Keyword(s):  
Splice Site ◽  
High Frequency ◽  
Splice Site Mutation ◽  
Site Mutation ◽  
Hydroxylase Deficiency ◽  
21 Hydroxylase Deficiency

scholarly journals Molecular diagnosis of patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Tania Mayvel Espinosa Reyes ◽  
Teresa Collazo Mesa ◽  
Paulina Arasely Lantigua Cruz ◽  
Adriana Agramonte Machado ◽  
Emma Domínguez Alonso ◽  
...  
Keyword(s):  
Congenital Adrenal Hyperplasia ◽  
Point Mutations ◽  
Adrenal Hyperplasia ◽  
Hydroxylase Deficiency ◽  
Cross Sectional ◽  
Salt Wasting ◽  
Frequent Mutations ◽  
Detection Of Mutations ◽  
21 Hydroxylase Deficiency ◽  
Intron 2

Abstract Background Congenital adrenal hyperplasia (CAH) is an autosomal recessive group of diseases. 21-Hydroxylase deficiency (21OHD) accounts for between 95 and 99% of all CAH cases. Objectives To characterize the genotype of patients clinically diagnosed with 21OHD and to identify the most frequent mutations in the Cuban population. Methods Cross-sectional descriptive study that included all patients diagnosed with 21OHD from January 2000 to December 2018. For the molecular analysis of the CYP21A2 gene, a protocol was used that used the polymerase chain reaction in 2 stages; in the first stage genomic DNA was amplified and 5 point mutations were detected in the second stage (Intron 2, Deletion of 8 bp, G318X, I172N and P30L). Results The 5 point mutations were identified in 31 of the 55 (56%) studied patients, 16/21 (76%) in the salt-wasting, 12/18 (67%) in the simple virilizing and 3/16 (19%) in the nonclassical form. The Intron 2 mutation was the most frequent, followed by G318X and 8 bp deletion. Compound heterozygotes were found in 10 patients, all corresponded to classic forms of the disease. Conclusions The causal CYP21A2 gene mutation was detected in 56% (72% in classic CAH), which makes the method encouraging. The most frequent mutations observed were Intron 2 and G318X. The detection of mutations offers confirmation of diagnosis, prediction of phenotype and genetic counseling.

scholarly journals Heterozygosis for CYP21A2 mutation considered as 21-hydroxylase deficiency in neonatal screening

2008 ◽  
Vol 52 (8) ◽  
pp. 1388-1392 ◽  
Author(s):  
Fernanda Caroline Soardi ◽  
Sofia Helena V. Lemos-Marini ◽  
Fernanda Borchers Coeli ◽  
Víctor Gonçalves Maturana ◽  
Márcia Duarte Barbosa da Silva ◽  
...  
Keyword(s):  
Splice Site ◽  
Neonatal Screening ◽  
Compound Heterozygous ◽  
Adrenal Hyperplasia ◽  
Hydroxylase Deficiency ◽  
Molecular Features ◽  
Molecular Studies ◽  
17 Hydroxyprogesterone ◽  
21 Hydroxylase Deficiency ◽  
Intron 4

Steroid 21-hydroxylase deficiency (21-OHD) accounts for more than 90% of congenital adrenal hyperplasia. CAH newborn screening, in general, is based on 17-hydroxyprogesterone dosage (17-OHP), however it is complicated by the fact that healthy preterm infants have high levels of 17-OHP resulting in false positive cases. We report on molecular features of a boy born pre-term (GA = 30 weeks; weight = 1,390 g) with elevated levels of 17-OHP (91.2 nmol/L, normal < 40) upon neonatal screening who was treated as having CAH up to the age of 8 months. He was brought to us for molecular diagnosis. Medication was gradually suspended and serum 17-OHP dosages mantained normal. The p.V281L mutation was found in compound heterozygous status with a group of nucleotide alterations located at the 3' end intron 4 and 5' end exon 5 corresponding to the splice site acceptor region. Molecular studies continued in order to exclude the possibility of a nonclassical 21-OHD form. The group of three nucleotide changes was demonstrated to be a normal variant since they failed to interfere with the normal splicing process upon minigene studies.

A Common Splice Site Mutation Is Shared by Two Families with Different Type 2N von Willebrand Disease Mutations

1999 ◽  
Vol 82 (09) ◽  
pp. 1061-1064 ◽  
Author(s):  
Kingsley Hampton ◽  
F. Eric Preston ◽  
Ian Peake ◽  
Anne Goodeve ◽  
I. Mandy Nesbitt
Keyword(s):  
Splice Site ◽  
Direct Sequencing ◽  
Splice Site Mutation ◽  
Von Willebrand Disease ◽  
The Other ◽  
Compound Heterozygous ◽  
Site Mutation ◽  
Disease Mutations ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryUsing an ELISA-based method to detect type 2N von Willebrand disease (VWD), we found two individuals with absent FVIII binding. Direct sequencing of the FVIII binding region of the von Willebrand factor (VWF) gene showed that one individual had an R854Q substitution whilst the other had a T791M substitution. The very low FVIII binding and the VWF:Ag levels in both individuals suggested a second defect on the other VWF allele. Conformation sensitive gel electrophoresis of polymerase chain reaction amplified DNA was used to detect an additional change in the VWF gene of each patient. Direct sequencing confirmed a previously unreported G to A transition in the donor splice site in intron 25 of both individuals which should result in a null allele. This was confirmed by mRNA analysis. These two individuals therefore have compound heterozygous VWD in which the only expressed allele has a type 2N mutation. In our population, such compound heterozygosity appears to be a significant cause of type 2N VWD.

scholarly journals Multiple transcripts of the CYP21 gene are generated by the mutation of the splicing donor site in intron 2 from GT to AT in 21-hydroxylase deficiency

2001 ◽  
Vol 171 (3) ◽  
pp. 397-402 ◽  
Author(s):  
HH Lee ◽  
SF Chang
Keyword(s):  
Donor Site ◽  
Splice Acceptor Site ◽  
Splice Donor Site ◽  
Acceptor Site ◽  
Site Mutation ◽  
Hydroxylase Deficiency ◽  
Exon 2 ◽  
Eukaryotic Genes ◽  
21 Hydroxylase Deficiency ◽  
Intron 2

Maturation of primary RNA transcripts of eukaryotic genes often involves the removal of introns and joining of exons. The fidelity of RNA splicing is dependent on the identity of the nucleotide (nt) sequences at exon/intron boundaries. Most importantly, the highly conserved intronic 5'GT and 3'AG sequences are essential for correct splicing. Substitution of GT by any other nt leads to incomplete mRNA and a disruption of protein structure. We describe here the results of our transfection experiments in COS-1 cells with a CYP21 genomic construct that contained an IVS 2+1G-->A mutation. Analysis of the transcripts by RT-PCR revealed that two different transcripts were generated by this mutant genome. In all the splicing products, we found that the entire exon 2 was deleted. Surprisingly, 30% of the transcripts from this mutant CYP21 genome were accompanied by an inclusion of 3' intron 2 sequences due to the use of a different splice acceptor site. This is the first report of the molecular characterization of a splice donor site mutation in CYP21 via transcription in COS-1 cells.

scholarly journals Genotype-phenotype associations in non-classical steroid 21-hydroxylase deficiency

2000 ◽  
pp. 397-403 ◽  
Author(s):  
N Weintrob ◽  
C Brautbar ◽  
A Pertzelan ◽  
Z Josefsberg ◽  
Z Dickerman ◽  
...  
Keyword(s):  
Precocious Puberty ◽  
Phenotypic Expression ◽  
Ethnic Origin ◽  
Stepwise Logistic Regression ◽  
Compound Heterozygous ◽  
Significant Variable ◽  
Hydroxylase Deficiency ◽  
Severe Mutation ◽  
Group B ◽  
21 Hydroxylase Deficiency

OBJECTIVE: To evaluate whether genotype differences can explain the clinical variability of non-classical steroid 21-hydroxylase deficiency (NC21-OHD) and to determine if genotype is related to ethnic origin. DESIGN: Genotyping for mutations in the steroid 21-hydroxylase (CYP21) gene was performed in 45 unrelated Israeli Jewish patients (nine males) with NC21-OHD (60min 17-hydroxyprogesterone (17-OHP), 45-386nmol/l) who were referred for evaluation of postnatal virilization or true precocious/early puberty. Eleven siblings diagnosed through family screening were genotyped as well. METHODS: Patients were divided by genotype into three groups: (A) homozygous or compound heterozygous for the mild mutations (V281L or P30L) (n=29; eight males); (B) compound heterozygous for one mild and one severe mutation (Q318X, I2 splice, I172N) (n=12; no males); (C) mild mutation detected on one allele only (n=4; one male; peak 17-OHP 58-151nmol/l). We then related the genotype to the ethnic origin, clinical phenotype and hormone level. Since group C was very small, comparisons were made between groups A and B only. RESULTS: At diagnosis, group B tended to be younger (5. 8+/-3.0 vs 8.1+/-4.3 years, P=0.09), had greater height SDS adjusted for mid-parental height SDS (1.6+/-1.1 vs 0.7+/-1.4, P=0.034), tended to have more advanced bone age SDS (2.9+/-1.5 vs 1.7+/-2.1, P=0.10) and had a higher peak 17-OHP level in response to ACTH stimulation (226+/-92 vs 126+/-62nmol/l, P<0.01). Group B also had pubarche and gonadarche at an earlier age (5.1+/-2.4 vs 7.4+/-2.2 years, P<0.01 and 7.4+/-1.8 vs 9.9+/-1.4 years, P<0.001, respectively) and a higher rate of precocious puberty (50 vs 17%, P=0.04). Stepwise logistic regression analysis (excluding males) yielded age at gonadarche as the most significant variable differentiating the two groups, with a positive predictive value of 86% for a cut-off of 7.5 years. CONCLUSIONS: The findings suggest that genotype might explain some of the variability in the phenotypic expression of NC21-OHD. Compound heterozygotes for one mild and one severe mutation have a higher peak 17-OHP associated with pubarche and gonadarche at an earlier age and more frequent precocious puberty. Hence, the severity of the enzymatic defect might determine the timing and pattern of puberty.

Hypofibrinogenaemia with Compound Heterozygosity for Two γ Chain Mutations – γ 82 Ala→Gly and an Intron Two GT→AT Splice Site Mutation

2000 ◽  
Vol 84 (09) ◽  
pp. 449-452 ◽  
Author(s):  
Jane Wyatt ◽  
Stephen May ◽  
Peter George ◽  
Stephen Brennan
Keyword(s):  
Splice Site ◽  
Splice Site Mutation ◽  
The Novel ◽  
Normal Pattern ◽  
Site Mutation ◽  
Reverse Phase ◽  
Sds Page ◽  
Mother And Daughter ◽  
History Of ◽  
Intron 2

SummaryWe investigated the molecular basis of hypofibrinogenaemia in a woman with a history of recurrent, pregnancy-associated bleeding, and miscarriage. She had a Clauss fibrinogen of 0.9 mg/ml and SDS PAGE of purified fibrinogen showed a normal pattern of chains. However careful inspection of reverse phase chain separation profiles showed apparent homozygosity for a more hydrophilic form of the γ chain. DNA Sequencing showed only heterozygosity for a CGT→GGT (Ala→Gly) mutation at codon γ82, but further sequencing showed an additional GT splice sequence mutation at the 5’ end of intron 2 of the γ gene. Translation of mRNA containing this intron would result in premature truncation explaining the phenotypic homozygosity of the γ82 Ala→Gly substitution. The patient’s sister had a mild bleeding disorder with hypofibrinogenaemia and she too was a compound heterozygote for the γ mutations. Her nephew had only the novel splice site mutation, while her mother and daughter inherited only the γ82 Ala→Gly substitution.

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