Molecular Analysis of CYP21A2 Gene Mutations among Iraqi Patients with Congenital Adrenal Hyperplasia

Table 4

Frequency of detected CYP21A2 mutations and zygosity status among Iraqi CAH patients.

Type of mutation	Number of cases (number of alleles carrying that mutation)		Number (%) of mutant alleles
	Homozygous	Heterozygous
P30L	0	0	0
I2Splice	8 (16)	2 (2)	18 (14.5%)
Del 8 bp	1 (2)	2 (2)	4 (3.2%)
I172N	5 (10)	0	10 (8.1%)
Cluster E6	0	0	0
V281l	1 (2)	3 (3)	5 (4.03%)
L307 frameshift	0	0	0
Q318X	4 (8)	4 + 2 (6)	14 (11.3%)
R356W	0	0	0
P453S	0	1 (1)	1 (0.81%)
R483P	0	1 (1)	1 (0.81%)
Large deletions/conversions	12 (24)	0	24 (19.3%)
Total detected	31 (62)	11 (13)	77 mutations in 75 alleles (60.5%)
Undetected	20 (40 + 9)		49 (39.5%)
Total cases	62 (124)

Two of these heterozygous cases were compound, each having 3 mutations (namely, I2Splice, Del 8 bp, and Q318X) in their 2 alleles.
^#Additional 9 alleles were undetected in the 9 heterozygous cases; only one mutation was detected.
Thirteen mutant alleles were detected in 11 patients (nine of them had a single detected mutation but the remaining two had 3 mutations as mentioned above).