Related Experiment Video
Updated: Jul 11, 2026

Generating CRISPR/Cas9 Mediated Monoallelic Deletions to Study Enhancer Function in Mouse Embryonic Stem Cells
Published on: April 2, 2016
Frequent deletion and duplication of the steroid 21-hydroxylase genes
Abstract:
Congenital adrenal hyperplasia due to 21-hydroxylase (21-OHase) deficiency is an HLA-linked disorder resulting from a mutation in the 21-OHase B gene encoding the adrenal cytochrome P450 specific for steroid 21-hydroxylation. To identify polymorphisms associated with 21-OHase deficiency, DNA samples from 22 unrelated patients with this disorder were examined with a human cDNA clone encoding the enzyme. Deletions of the active 21-OHase gene were found in almost one-fourth of classical 21-OHase deficiency alleles. In contrast, mild, "nonclassical" 21-OHase deficiency is associated with a duplicated 21-OHase gene.
Related Concept Videos
Nondisjunction
Gene Families
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
Genome Copying Errors
Gene Duplication and Divergence
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.
Exon Recombination
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Nondisjunction

