title: CYP21B gene conversion and complete CYP21A gene deletion in congenital adrenal hyperplasia.
abstract: 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.
authors.affiliation: Laboratoire de Biochimie Endocrinienne du Développement et de la Reproduction, CHRU Lapeyronie, Montpellier, France.
authors.forename: J M
authors.initials: JM
authors.lastname: Lobaccaro
authors.forename: N
authors.initials: N
authors.lastname: Ghanem
authors.forename: G
authors.initials: G
authors.lastname: Lefranc
authors.forename: C
authors.initials: C
authors.lastname: Sultan
mesh_terms: D000312:Adrenal Hyperplasia, Congenital / Q000235:genetics*; D000328:Adult; D001426:Bacterial Proteins; D003181:Complement C4 / Q000235:genetics; D011415:Complement Factor B / Q000235:genetics; D015342:DNA Probes; D003720:Densitometry; D015252:Deoxyribonucleases, Type II Site-Specific; D005260:Female; D005785:Gene Conversion; D006801:Humans; D008297:Male; D012150:Polymorphism, Restriction Fragment Length; D011544:Pseudogenes; D013255:Steroid 21-Hydroxylase / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D003181:Complement C4; D015342:DNA Probes; D013255:Steroid 21-Hydroxylase; C024404:BglII endonuclease; D015252:Deoxyribonucleases, Type II Site-Specific; C027046:TCGA-specific type II deoxyribonucleases; D011415:Complement Factor B