Molecular analysis of the CYP21 gene and prenatal diagnosis in families with 21-hydroxylase deficiency in northeastern Iran.
OBJECTIVE
A rapid and convenient approach for the detection of the most common CYP21 gene mutations in patients with congenital adrenal hyperplasia (CAH) with classical forms of 21-hydroxylase deficiency was used. In addition, a new semiquantitative strategy for the detection of del8-bp was designed. These procedures were used for prenatal diagnosis and genotype-phenotype correlation in northeastern Iran.


METHODS
Molecular analysis of the CYP21 gene for the detection of the 9 most common mutations (CYP21gene deletion, P30L, i2g, del-8bp, I172N, E6 cluster, V281L, Q318X and R356W) was performed on 30 CAH patients and for prenatal diagnosis in 2 cases.


METHODS
Restriction fragment length polymorphism, amplification-created restriction sites, allele-specific polymerase chain reaction (PCR) and semiquantitative PCR were performed.


RESULTS
We characterized 90% of the CAH chromosomes. The most frequent mutations in the CYP21 gene were del-CYP21 (25%), I172N (22%) and i2g (15%). Unlike in other ethnic groups, there was no R356W mutation, however, a higher rate of del-8bp (10%) was found in our population. Wealso found 6 complex alleles in our patients. For 2 families prenatal CYP21 gene analysis resulted in the diagnosis of healthy fetuses and termination of dexamethasone treatment in the 15th week of gestation. Genotype-phenotype correlation was observed. The rate of homozygosity (50%) was greater than the predicted values due to the higher rate of parental consanguinity in our population.


CONCLUSIONS
These molecular procedures proved to be sensitive and rapid for the detection of the most common mutations of the CYP21 gene and prenatal diagnosis. Increased 17-hydroxyprogesterone, found in neonatal CAH screening, can be confirmed by these mutation analyses.
Vakili
Rahim
R
Division of Endocrinology and Metabolism, Department of Pediatrics, Imam Reza Hospital, Mashhad University of Medical Sciences, Iran.
Baradaran-Heravi
Alireza
A
Barid-Fatehi
Babak
B
Gholamin
Mehran
M
Ghaemi
Nosrat
N
Abbaszadegan
Mohammad Reza
MR
D000293:Adolescent; D000312:Adrenal Hyperplasia, Congenital / Q000235:genetics*; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D005820:Genetic Testing / Q000379:methods*; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007492:Iran; D008297:Male; D010641:Phenotype; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D013255:Steroid 21-Hydroxylase / Q000235:genetics*
D013255:Steroid 21-Hydroxylase