English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Steroid 21-hydroxylase deficiency is the most common enzymatic defect causing congenital adrenal hyperplasia, an inherited disorder of cortisol biosynthesis. All mutations thus far characterized that cause this disorder appear to result from recombinations between the gene encoding the enzyme, CYP21B (CYP21), and the adjacent pseudogene, CYP21A (CYP21P). These are either deletions caused by unequal crossing-over during meiosis or apparent transfers of deleterious sequences from CYP21A to CYP21B, a phenomenon termed gene conversion. However, a small percentage of alleles do not carry such a mutation. We analyzed DNA from a patient with the mild, nonclassic form of 21-hydroxylase deficiency, who carried one allele that had no gene conversions detectable by hybridization with oligonucleotide probes. Sequence analysis revealed that this allele carried two missense mutations, R339H and P453S, neither of which has been previously observed in CYP21A or CYP21B. Each of these mutations was introduced into CYP21 cDNA which was then expressed in COS1 cells using a vaccinia virus system. Each mutation reduced the ability of the enzyme to 21-hydroxylate 17-hydroxyprogesterone to 50% of normal and the ability to metabolize progesterone to 20% of normal. Thus, each of these mutations represents a potential nonclassic 21-hydroxylase deficiency allele that is not the result of an apparent gene conversion.

R339H and P453S: CYP21 mutations associated with nonclassic steroid 21-hydroxylase deficiency that are not apparent gene conversions.