Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0235394 (wasting)
 8,040 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Steroid 21-hydroxylase deficiency is the major cause of congenital adrenal hyperplasia. Genotyping for deletions and nine point mutations in the CYP21 gene has been performed in 38 Spanish patients and their relatives by Southern blot analysis and allele-specific oligonucleotide hybridization. Three clinical variants were included in this study, viz., salt-wasting (SW, 21 patients), simple virilizer (SV, two patients), and late-onset (LO, 15 patients) forms. Twenty-three patient genotypes (16 SW, two SV, and five LO) were fully characterized. In both alleles, all but one of these severe forms (SW and SV) presented mutations that abolished or severely affected enzymatic activity. Patients with LO forms showed mutations that moderately impaired enzymatic activity in both alleles, or severe mutations in only one chromosome. Of 46 chromosomes from severe forms, 41 were characterized in this study (89%). The most frequent mutation was an aberrant splicing site (655 A or C to G) in intron 2, in 30% of these chromosomes. Deletions were found in 20%, and large gene conversions in 13% of these alleles. This screening allowed the characterization of 18 out of 30 LO chromosomes, the most frequent mutation being Val281Leu (37%). Severe mutations were found, in heterozygosis, in one third of LO patients.
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PMID:Analysis of steroid 21-hydroxylase gene mutations in the Spanish population. 763 70

Patients with salt-wasting congenital adrenal hyperplasia (SW-CAH) most commonly carry an A-G transition at nucleotide 656 (nt 656 A-->G), causing abnormal splicing of exons 2 and 3 in CYP21, the gene encoding active steroid 21-hydroxylase. Affected infants are severely deficient in cortisol and aldosterone, and usually come to medical attention during the neonatal period. We report on 2 affected boys, homozygous for the nt 656 mutation, who thrived in early infancy, but suffered salt-wasting crises unusually late in infancy, at 3.5 and 5.5 months, respectively. Laboratory studies at presentation showed hyponatremia, hyperkalemia, dehydration, and acidosis; serum aldosterone was low in spite of markedly elevated plasma renin activity. Basal 17-hydroxyprogesterone levels were only moderately elevated, yet the stimulated levels were more typical of severe, classic CAH due to 21-hydroxylase deficiency. Genomic DNA from the patients was analyzed. Southern blot showed no major deletions or rearrangements. CYP21-specific amplification by polymerase chain reaction, coupled with allele-specific hybridization using wild-type and mutant probes at each of 9 sites for recognized disease-causing mutations, revealed a single, homozygous mutation in each patient: nt 656 A-->G. These results were confirmed by sequence analysis. We conclude that the common nt 656 A-->G mutation is sometimes associated with delayed phenotypic expression of SW-CAH. We speculate that variable splicing of the mutant CYP21 may modify the clinical manifestations of this disease.
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PMID:Splicing mutation in CYP21 associated with delayed presentation of salt-wasting congenital adrenal hyperplasia. 767 50

Mutations in 21 hydroxylase gene were investigated in 40 Russian patients with congenital adrenal hyperplasia. Quantitative amplification/restriction procedure was used for detection of mutations involving promoter region, 3 and 8 exons. For affected chromosomes alleles of tightly linked HLA A and B genes were defined, as well as 5 different alleles or allele combinations HLA DQA1 gene. The most frequent (> 20% of chromosomes) cause of salt wasting adrenal hyperplasia in Russia is a chimeric CYP21A-CYP21B gene with normal copy of a pseudogene which results from gene conversion in chromosome with B14-DQA1 0101/0102 haplotype. The second common mutation (about 10%) is a result of intragenic recombination well-known deletion of the gene linked with A3-B47-DQA1 0201/0601 haplotype. Two other mutations were linked with A3-B35-DQA1 0401/0402 and A3-B40-DQA1 0201/0601 haplotypes.
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PMID:Preliminary investigation of mutations in 21-hydroxylase gene in patients with congenital adrenal hyperplasia in Russia. 774 11

Congenital adrenal hyperplasia, caused by any one of a number of inborn errors of steroidogenesis in which cortisol is not sufficiently produced by the adrenal cortex, is in most cases due to a deficiency of the enzyme steroid 21-hydroxylase. Classic 21-hydroxylase deficiency occurs in about 1 in 14,000 live births. In classic 21-hydroxylase deficiency, the most common cause of genital ambiguity in females, prenatal exposure to excess androgens results in virilization of the female fetus. Newborn males have normal genitalia. Postnatally, untreated females as well as males present with signs of androgen excess. Three fourths of classic 21-hydroxylase deficiency cases do not effectively synthesize aldosterone and are salt-wasting, a condition that is potentially fatal. An allelic variant of classic 21-hydroxylase deficiency, termed nonclassic 21-hydroxylase deficiency, is associated with a milder enzymatic defect and no genital ambiguity at birth, but postnatal virilization may be seen. The 21-hydroxylase enzyme, a cytochrome P450 hemeprotein (cytochrome P450c21), is encoded by the gene CYP21, which has a closely neighboring homologous pseudogene, CYP21P. Mutations in the CYP21 gene, causing 21-hydroxylase deficiency, are common and occur owing to two mechanisms: gene deletion and apparent gene conversion. Prenatal diagnosis is important to identify a fetus affected with 21-hydroxylase deficiency. Genital ambiguity in affected females can be prevented by proper administration of dexamethasone to the pregnant mother. Postnatally, the treatment of 21-hydroxylase deficiency is lifelong hormonal replacement. With carefully supervised medical treatment, congenital adrenal hyperplasia patients have the capacity for normal puberty and fertility.
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PMID:Steroid 21-hydroxylase deficiency (congenital adrenal hyperplasia). 782 36

Steroid 21-hydroxylase deficiency is a major cause of congenital adrenal hyperplasia and is caused by genetic impairment of this enzyme. Since approximately 80% of cases are caused by point mutations of the CYP21B (CYP21A2) gene, whereas the remaining 20% are due to deletion of this gene, we used the polymerase chain reaction single strand conformation polymorphism technique for rapid and accurate diagnosis of this disease. Of 23 patients examined, 1 had a hemizygous CYP21B gene. 18 patient's genes localized their harmful mutations or deletion on both the alleles, while 4 of them found their causative mutations on one of the two alleles, and 1 failed to find any responsible mutation. All the mutations (four nucleotide substitutions) detected are also found in the CYP21A (CYP21A1) pseudogene. A mutation at the intron 2 site is most prevalent in both salt-wasting and simple virilizing forms of the disease, and accounts for 37% of the patient's genes (17/46). Pedigree analysis of these mutations revealed that the mutations (at least four of them) occurred de novo at a considerable frequency on both the paternally and maternally inherited chromosomes. This result could explain occasional discordance of the diagnosis using HLA typing with the clinical symptoms.
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PMID:Molecular analysis of patient and carrier genes with congenital steroid 21-hydroxylase deficiency by using polymerase chain reaction and single strand conformation polymorphism. 822 33

Disorders of the CYP21 gene, which is located within the major histocompatibility complex on the short arm of chromosome 6, are the leading causes of congenital adrenal hyperplasia (CAH). The coding gene and a highly homologous pseudogene are tandemly arranged with the two genes for the fourth component of complement (C4A and C4B). To analyse the prevalence rates of mutations of the CYP21 genes and the segregation of the CYP21 genes with their corresponding human leucocyte antigen (HLA)-haplotypes, 21 families with one or two children with the severe form of 21-hydroxylase deficiency were studied. Mutations of the CYP21 gene on their corresponding HLA-haplotype were detected by hybridisation of polymerase chain reaction (PCR)-amplified genomic DNA with sequence-specific oligonucleotides and solid phase direct sequencing. Our study has shown the following. (1) A single basepair mutation (A-->G or C-->G) within the second intron is the most frequent mutation leading to impaired 21-hydroxylase activity. This mutation is only detected in HLA-haplotypes associated with the salt-wasting form of CAH. (2) A large deletion of part or all of the CYP21 gene is associated with the HLA-haplotype A3, BW47, C6, DR7, DR53, DQ2 but is also observed in other HLA-haplotypes and can be detected by a simple rapid PCR restriction fragment length polymorphism method. (3) Two alleles of the coding CYP21 gene differing in a leucine codon within the first exon, (formerly described as a mutation associated with 21-hydroxylase deficiency) have been found with an equal distribution in patients with 21-hydroxylase deficiency, non-disease HLA-haplotypes and the local healthy controls.
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PMID:Altered CYP21 genes in HLA-haplotypes associated with congenital adrenal hyperplasia (CAH): a family study. 836 24

Direct DNA sequencing of the steroid 21-hydroxylase gene (CYP21) revealed two novel mutations in two patients with severe congenital adrenal hyperplasia. The nonsense mutation Trp23Stop (TGG --> TGA) was found in a woman with the simple virilizing form of the disease. She was a compound heterozygote, with the previously described Ile173Asn mutation on her other allele. A boy, who developed salt-wasting in the neonatal period, carried an allele with a novel mutation of the canonical splice acceptor site in intron 1 (AG --> GG). He was also a compound heterozygote, with the well-known splice mutation in intron 2 on his other allele.
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PMID:An intron 1 splice mutation and a nonsense mutation (W23X) in CYP21 causing severe congenital adrenal hyperplasia. 869 38

Congenital adrenal hyperplasia (CAH) is an inherited metabolic disease caused by the deficiency of one of the enzymes necessary for cortisol synthesis. Deficiency of 21-hydroxylase (21-OH) accounts for 95% of affected patients There are two forms of the disease. The first is classic, which may be incomplete (simple virilizing) or complete (salt wasting). The second is nonclassic, which may be symptomatic or asymptomatic. In classic 21-OH deficiency which occurs in 1:10000-15000 live births, prenatal exposure to excess androgens results in virilisation of female fetus. Newborn males have normal genitalia. Postnatally, untreated females as well as males present with signs of androgen excess. Three fourths of classic 21-OH deficiency cases do not effectively synthesize aldosterone and are salt wasting, a condition that is potentially fatal. Nonclassic 21-OH deficiency, allelic variant of classic 21-OH deficiency is associated with a milder enzymatic defect and no genital ambiguity at birth, but postnatal virilization may be seen. A subset of individuals with nonclassic 21-OH deficiency are asymptomatic, despite high levels of androgens (cryptic form of disease). The 21-OH enzyme, a cytochrome P450 hemoprotein (cytochrome P450 c21) is encoded by the gene CYP21, which has a closely neighboring homologous pseudogene, CYP21P. Mutations in the CYP21 gene, causing 21-OH deficiency, are common and occur owing to two mechanisms: gene deletion and apparent gene conversion. Prenatal diagnosis is important to identify a fetus affected with 21-OH deficiency. Genital ambiguity in affected females can be prevented by proper administration of dexamethasone to pregnant mother. Postnatally, the treatment of 21-OH deficiency is lifelong hormonal replacement. With carefully supervised medical treatment. CAH patients have the capacity for normal puberty and fertility.
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PMID:[Congenital adrenal hyperplasia due to 21-hydroxylase enzyme deficiency]. 875 1

Steroid 21-hydroxylase deficiency is among the most common inborn errors of metabolism in man. Characterization of mutations in the 21-hydroxylase gene (CYP21) has permitted genetic diagnosis, facilitated by the polymerase chain reaction (PCR). The most common mutation is conversion of an A or C at nt656 to a G in the second intron causing aberrant splicing of mRNA. Homozygosity for nt656G is associated with profoundly deficient adrenal cortisol and aldosterone synthesis, secondary hypersecretion of adrenal androgens, and a severe form of congenital adrenal hyperplasia (CAH) characterized by ambiguous genitalia and/or sodium wasting in newborns. During the course of genetic analysis of CYP21 mutations in CAH families, we and others have noticed a number of relatives genotyped as nt656G homozygotes, yet showing no clinical signs of disease. A number of lines of evidence have led us to propose that the putative asymptomatic nt656G/G individuals are incorrectly typed due to dropout of one haplotype during PCR amplification of CYP21. For prenatal diagnosis, we recommend that microsatellite typing be used as a supplement to CYP21 genotyping in order to resolve ambiguities at nt656.
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PMID:Identification of non-amplifying CYP21 genes when using PCR-based diagnosis of 21-hydroxylase deficiency in congenital adrenal hyperplasia (CAH) affected pedigrees. 896 61

The major cause of congenital adrenal hyperplasia (CAH), a common recessive genetic disease, is the deficiency of steroid 21-hydroxylase (21OH), a microsomal enzyme encoded by the CYP21 gene. Although several CAH causing mutations have been identified in the CYP21 gene of patients with 21OH deficiency, genotyping of the 21OH locus is quite complex because of the high frequency of gene conversion and the presence of multiple mutations on single CAH alleles. In order to perform the complete characterisation of the CYP21 gene coding region more simply, we developed a highly sensitive, non-radioactive method allowing DNA single strand conformation polymorphism (DNA-SSCP) analysis. This method was applied to the characterisation of all the exons and intron-exon junctions of the CYP21 gene in five patients affected by the simple virilising form and one affected by the salt wasting form. In all samples showing SSCP signals, direct sequence analysis showed the presence of more than one single sequence variant. In particular, four mutations which are already known to cause the disease, 16 polymorphisms, and one newly identified C to T transition at position 849 were detected. A random sequence analysis, performed on 31 out of 81 exons showing a normal SSCP pattern, shows the method to be highly sensitive: no sequence variant was detected, thus confirming the validity of this non-radioactive DNA-SSCP analysis in characterising the CYP21 gene in patients with steroid 21OH deficiency. Notwithstanding the complete characterisation of all exons and exon/intron junctions of the CYP21 gene, no complete genotype/phenotype correlation was found in the panel of patients analysed, thus suggesting that characterisation of CAH alleles must be extended to outside the coding region of the CYP21 gene, most probably into the promoter region.
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PMID:Characterisation of CAH alleles with non-radioactive DNA single strand conformation polymorphism analysis of the CYP21 gene. 913 94


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