Detected heterozygotes during the molecular analysis of the common CYP21A2 point mutations in Macedonian patients with congenital adrenal hyperplasia and their relatives.
BACKGROUND
Deficiency of 21-hydroxylase is present in 90-95% cases of congenital adrenal hyperplasia (CAH), an autosomal recessive disorder. Eleven common pseudogene-derived mutations account for approximately 95% of all affected CYP21A2 alleles in all three clinical forms of the disease.


OBJECTIVE
To analyse the detected heterozygotes during the molecular analysis of eleven CYP21A2 common pseudogene-derived point mutations in Macedonian CAH patients and their relatives, using the PCR-ACRS protocol.


METHODS
We performed direct molecular detection of CYP21A2 mutations: p.P30L, IVS2-655 C/A→G, G110Δ8nt, p.I172N, p.I236N, p.V237E, p.M239K, p.F306+t, p.V281L, p.Q318X and p.R356W, in 51 CAH Macedonian patients and their 70 healthy relatives (parents and siblings), using the differential PCR-ACRS protocol.


RESULTS
Six of the analysed mutations were detected in 29.4% (15/51) of the patients, in the heterozygous state, with the following distribution: IVS2-655 C/A→G (13.7%), p.P30L (11.8%), p.Q318X (9.8%), p.I172N (3.9%), p.R356W (3.9%) and p.V281L (1.96%). Six cases (6/15) were compound heterozygotes and nine (9/15) were simple heterozygotes. Genotype-phenotype correlation was observed in all of our detected compound heterozygote patients. Their clinical presentation was correlated with the less severely mutated allele. Four of the analysed mutations (p.P30L 20%, IVS2-655 C/A→G 12.9%, p.Q318X 7.1% and p.R356W 2.9%) appeared in thirty healthy relatives (42.9%), in the heterozygous state.


CONCLUSIONS
Distribution of the analysed CYP21A2 mutations among CAH patients and their relatives is comparable to studies from other populations. As expected, high carrier frequency of alleles causing 21-hydroxylase deficiency was observed in relatives of CAH patients.
Genetic Laboratory, Department of Endocrinology and Genetics University Children's Clinic, Medical Faculty, Ss. Cyril and Methodius University, Skopje, R. Macedonia.
Violeta
V
Anastasovska
Mirjana
M
Kocova
D000312:Adrenal Hyperplasia, Congenital / Q000235:genetics*; D006580:Genetic Carrier Screening; D006115:Greece; D006801:Humans; D017354:Point Mutation; D013255:Steroid 21-Hydroxylase / Q000235:genetics*
C531510:CYP21A2 protein, human; D013255:Steroid 21-Hydroxylase