Anka Tıp Dergisi
Yazarlar: Bakhtiyar MAMMADOV, Aysel KALAYCI YİĞİN, Filiz ÖZDEMİR, Ahmet ÖZAYDIN, Mehmet SEVEN
Konular:Genetik ve Kalıtım
Anahtar Kelimeler:Congenital adrenal hyperplasia,CYP21A2,CYP21P,MLPA
Özet: Congenital adrenal hyperplasia (CAH) belongs to the group of familial diseases with autosomal recessive inheritance, which is caused by a disorder of adrenal steroid production. It is caused by the deficiency of any of the five enzymes that provide cortisol synthesis from cholesterol in the adrenal cortex. Characteristic of CAH is ambiguous genital structure and impaired sexual development. The most common cause of CAH is 21-hydroxylase enzyme deficiency. The CAH, which is caused by 21-hydroxylase deficiency, has 2 types as 'classic' and 'non-classical'. The differences in the clinical picture depend on the structural and functional changes caused by mutations in the 21-hydroxylase gene. The two steroid 21-hydroxylase genes (CYP21A2 active gene, CYP21P pseudogene) are located on the short arm of chromosome 6. The mutations that cause defect of the active gene are due to the fact that active and pseudogene are very close and quite homologous. Deletions, duplications, gene conversions and point mutations occur as a result of intergenic recombination of the DNA sequence. Due to the presence of CYP21A2 pseudogene; there are often problems in diagnosing CAH, which develops due to 21-hydroxylase deficiency only with sequence analysis studies for the CYP21A2 gene. In this study; patients who were directed to Department of Medical Genetics in Cerrahpasa Medical Faculty for CYP21A2 gene mutation analysis were reevaluated with clinical and laboratory findings. It was aimed to determine the number of copy changes that could not be detected in the sequence analysis. Therefore; ensuring the treatment of the patients without delay in their diagnosis; In addition, it is aimed to demonstrate that MLPA method is an easy, relatively cheap, fast and reliable method in mutation analysis for the CYP21A2 gene. With the MLPA method, 28 patients were included in the study, homozygous deletion covering the majority of the gene in 1 patient, heterozygous deletion in 2 patients and heterozygous duplication in 1 patient were detected.