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)

We studied a family in which one out of two children presented a non-salt wasting form of CAH. Genomic DNA of the patient, his brother, his parents and a normal control were digested by the Taq I and Bgl II restriction enzymes. The fragments were electrophoresed, transferred onto a nitrocellulose membrane and hybridized with two specific probes: pC21a for the CYP21 genes and pAT-A for the C4 genes. We performed simultaneous RFLP analyses of the CYP21 and C4 genes and determined the relative hybridization intensity of the genes using scanning densitometry of the X-ray films. The affected child had a CYP21B gene conversion in the CYP21A pseudogene on one chromosome inherited from his mother and a mutated CYP21B gene on the second chromosome inherited from his father. The second maternal chromosome, inherited by the unaffected brother, presented an unusual CYP21A gene deletion without a C4A or C4B gene deletion. Although CYP21A is a pseudogene, this type of complete CYP21A gene deletion associated with a CYP21B gene conversion has never been previously described.
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PMID:CYP21B gene conversion and complete CYP21A gene deletion in congenital adrenal hyperplasia. 197 31

During our investigations of polymorphisms at, and in the immediate chromosomal vicinity of, the 21-hydroxylase locus in families with 21-hydroxylase deficiency, three families were found to show marked discordance in clinical features of HLA identical subjects. In one family, there is discordance between a boy with the simple virilising form of 21-hydroxylase deficiency and his two younger sisters, who are both HLA identical to their brother, but who have additional salt wasting features. In the other two families, one subject is severely affected and has very high 17-hydroxyprogesterone levels, but has an HLA identical sib who is asymptomatic and shows only slightly raised 17-hydroxyprogesterone levels. In all cases, HLA identity, as indicated by protein polymorphism studies (HLA-A, B, DR, C4A, C4B, and Bf typing), has been verified at the gene organisation level using 21-hydroxylase and complement C4 DNA probes. An HLA-Bw47 bearing haplotype in one of the latter families has not been transmitted to the affected child and appears to carry a normal 21-OHB allele and two genes which specify C4A allotypes.
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PMID:21-hydroxylase deficiency families with HLA identical affected and unaffected sibs. 278 76

Several autoimmune disorders as well as congenital adrenal hyperplasia (CAH) are either associated or closely linked with genetic variants of the fourth component of complement (C4A and C4B) and the enzyme steroid 21-hydroxylase (21-OH). These proteins are encoded by genes that are located downstream from the genes for complement proteins, C2 and factor B (BF) between HLA-B and -DR in the major histocompatibility complex (MHC). Previous studies of variants and null alleles were based on electrophoretic mobility of C4 protein and linkage with disease phenotypes. These data did not permit analysis of the basis for the observed null alleles and duplicated variants. We studied this region of the MHC in 126 haplotypes for a structural analysis of the four adjacent loci, C4A, 21-OHA, C4B, and 21-OHB. About half of the C4 genes typed as C4 null are deleted and several unrecognized homoduplicated C4 alleles were detected. Hence the frequencies of different C4 structural variants must be recalculated based on a direct analysis of the genes. Analysis of the C4/21-OH genes of patients with the classical (salt-wasting) form of CAH showed that some involve a deletion of the C4B and 21-OHB genes; whereas for two only the 21-OHB gene is deleted, i.e., the C4B gene is present. Together, these data provide a better understanding of the mechanisms generating and importance of deleted C4 and 21-OH null alleles in human disease.
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PMID:Polymorphism of the human complement C4 and steroid 21-hydroxylase genes. Restriction fragment length polymorphisms revealing structural deletions, homoduplications, and size variants. 301 42

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

We determined the frequency of large rearrangements and point mutations in 130 Brazilian patients with 21-hydroxylase deficiency and correlated genotype with phenotype. The frequency of CYP21 deletions was lower (4.4%) than in most of the previous series described, whereas the frequency of large gene conversions was similar to the frequency reported in the literature (6.6%). The most frequent point mutations were I2 splice (41.8% in salt wasting - SW), I172N (32.6% in simple virilizing - SV) and V281L (40.2% in the late onset form - LO). The frequency of the nine most common point mutations was similar to that reported for other countries. The 93 fully genotyped patients were classified into 3 mutation groups based on the degree of enzymatic activity (A<2%, B approximately 2%, C>20%). In group A, 62% of cases presented the SW form; in group B, 96% the SV form, and in group C, 88% the LO form. We diagnosed 80% of the affected alleles after screening for large rearrangements and 15 point mutations. To diagnose these remaining alleles we sequenced the CYP21 gene of one patient with the SV form and identified a heterozygous G-->A transition in codon 424. This mutation leads to a substitution of glycine by serine in a conserved region and was also found in a compound heterozygous state in 4 other patients. The mutation G424S presented a linkage disequilibrium with CYP21P and C4A gene deletions and HLA DR17, suggesting a probable founder effect. Search for the G424S mutation in other populations will reveal if it is restricted to the Brazilian patients or if it has a wider ethnic distribution.
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PMID:21-Hydroxylase deficiency in Brazil. 1100 22

The aim of this work was to analyse C4 genotypes, C4 protein levels, phenotypes and genotypes in patients with the classical form of 21-hydroxylase deficiency. Fifty-four patients from 46 families (36 female, 18 male; mean age 10.8 years) with different clinical manifestations (31 salt-wasting; 23 simple-virilizing) were studied. Taq I Southern blotting was used to perform molecular analysis of the C4/CYP21 gene cluster and the genotypes were defined according to gene organization within RCCX modules. Serum C4 isotypes were assayed by enzyme-linked immunosorbent assay. The results revealed 12 different haplotypes of the C4/CYP21 gene cluster. Total functional activity of the classical pathway (CH50) was reduced in individuals carrying different genotypes because of low C4 concentrations (43% of all patients) to complete or partial C4 allotype deficiency. Thirteen of 54 patients presented recurrent infections affecting the respiratory and/or the urinary tracts, none of them with severe infections. Low C4A or C4B correlated well with RCCX mono-modular gene organization, but no association between C4 haplotypes and recurrent infections or autoimmunity was observed. Considering this redundant gene cluster, C4 seems to be a well-protected gene segment along the evolutionary process.
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PMID:Complement 4 phenotypes and genotypes in Brazilian patients with classical 21-hydroxylase deficiency. 1913 35