Table 4.
CYP21A2 Mutations Found in 129 Unrelated Patients with 21-OHD
| Type | Allele No. | Frequency in 262 alleles (%) |
|---|---|---|
| Classic chimeric CYP21A1P/CYP21A2∗ | ||
| CH-1 | 30 | 11.45 |
| CH-2 | 0 | 0.00 |
| CH-3 | 4 | 1.53 |
| CH-5 | 29 | 11.07 |
| CH-6 | 0 | 0.00 |
| CH-7 | 0 | 0.00 |
| CH-8 | 13 | 4.96 |
| Total | 76 | 29.01 |
| Attenuated chimeric CYP21A1P/CYP21A2∗ | ||
| CH-4 | 3 | 1.15 |
| CH-9 | 0 | 0.00 |
| Total | 3 | 1.15 |
| Total chimeric CYP21A1P/CYP21A2 | ||
| 79 | 30.15 | |
| Most common mutations† | ||
| In2G | 62 | 23.66 |
| V281L | 47 | 17.94 |
| I172N | 36 | 13.74 |
| Q318X | 11 | 4.20 |
| R356W | 9 | 3.44 |
| L307fx15 | 6 | 2.29 |
| E6cluster | 5 | 1.91 |
| G110fsX21 | 2 | 0.76 |
| P30L | 1 | 0.38 |
| Other point mutations | ||
| 16 | 6.11 | |
| CYP21A2 duplications | ||
| 4 | 1.53 | |
∗
Chimeric types were assigned according to Chen et al.8
†
Nomenclature at the protein level is based on conventional codon numbering. Nomenclature at the cDNA level, based on ENST00000418967, is as follows: P30L (c.92C>T), In2G (c.293-13A/C>G), G110fsX21 (c.332_339del), I172N (c.518T>A), D183E (c.552C>G), D234D (c.705T>C), E6cluster [I236N (c.710T>A), V237E (c.713T>A), M239K (c.719T>A)], V281L (c.844G>T), L307fx15 (c.923_924insT), Q318X (c.955C>T), and R356W (c.1069C>T); 21-OHD, 21-hydroxylase deficiency.