Table 4: Frequency of detected CYP21A2 mutations and zygosity status among Iraqi CAH patients.

Type of mutationNumber of cases (number of alleles carrying that mutation)Number (%) of mutant alleles
HomozygousHeterozygous

P30L000
I2Splice8 (16)2 (2)18 (14.5%)
Del 8 bp1 (2)2 (2)4 (3.2%)
I172N5 (10)010 (8.1%)
Cluster E6000
V281l1 (2)3 (3)5 (4.03%)
L307 frameshift000
Q318X4 (8)4 + 2 (6)14 (11.3%)
R356W000
P453S01 (1)1 (0.81%)
R483P01 (1)1 (0.81%)
Large deletions/conversions12 (24)024 (19.3%)

Total detected31 (62)11 (13)77 mutations in 75 alleles (60.5%)

Undetected20 (40 + 9)49 (39.5%)

Total cases62 (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).