Table 2. Frequency of mosaicism for each reported gene considering probands who were mosaic for a pathogenic or likely pathogenic variant in the corresponding gene.
| Gene | Disease/phenotype | Primary transcript | Percent of probands with mosaic variants | No. of mosaic variants/total no. of pathogenic and likely pathogenic variants | 95% CI | Percent of de novo variants detected by multigene panels when both parents tested by targeted dideoxy sequencing (no. of de novo variants/no. of cases tested) | Percent of de novo variants for positive cases when tested via trio-based WES |
|---|---|---|---|---|---|---|---|
| CDKL5 | Atypical RS, EIEE | NM_003159.2 | 8.8% | 8/91 | 0.039–0.166 | 100% (26/26) | 100% (6/6) |
| PCDH19 | EIEE (EFMR) | NM_001184880.1 | 8.2% | 6/73 | 0.031–0.170 | 75.9% (22/29) | 40% (2/5) |
| SCN2A | EIEE, BFNIS, GEFS+, IS, ICE | NM_021007.2 | 6.4% | 7/110 | 0.026–0.128 | 89.8% (44/49) | 95.2% (20/21) |
| SCN1A | GEFS+, ICE-GTCS, EIEE, SMEI, DS | NM_001165963.1 | 1.3% | 4/320 | 0.003–0.032 | 75.5% (74/98) | 73.7% (14/19) |
| GABRA1 | OS, DS, IS, GEFS+, JME, CAE | NM_000806.5 | 12.5% | 2/16 | 0.016–0.384 | 100% (8/8) | 100% (2/2) |
| GRIN2B | EIEE, ID | NM_000834.3 | 6.3% | 1/16 | 0.002–0.302 | 50% (1/2) | 100% (12/12) |
| GABRG2 | FS, FS with CAE, GEFS+ | NM_000816.3 | 4.2% | 1/24 | 0.001–0.211 | 73.3% (11/15) | 50% (1/2) |
| MECP2 | RS, atypical RS | NM_004992.3 | 1.1% | 1/88 | 0.0003–0.062 | 77.8% (7/9) | 81% (17/21) |
| KCNQ2 | BFNS, EIEE | NM_172107.2 | 0.6% | 1/155 | 0.001–0.035 | 81.5% (44/54) | 88.2% (15/17) |
| Total | 3.5% | 31/893 | 0.024–0.049 | 81.7% (237/290) | 84.8% (89/105) |
BFNIS, benign familial neonatal–infantile seizures; BFNS, benign familial neonatal seizures; CAE, childhood absence epilepsy; DS, Dravet syndrome; EFMR, epilepsy and mental retardation limited to females; EIEE, early infantile epileptic encephalopathy; FS, febrile seizures; GEFS+, genetic (generalized) epilepsy with febrile seizures plus; ICE, intractable childhood epilepsy; ICE-GTCS, intractable childhood epilepsy with generalized tonic–clonic seizures; ID, intellectual disability; IS, infantile spasms; JME, juvenile myoclonic epilepsy; OS, Ohtahara syndrome; RS, Rett syndrome; SMEI, severe myoclonic epilepsy of infancy; WES, whole-exome sequencing.
95% confidence interval (CI) is provided.