Genetic stratification of 161 unrelated PCD families, according to TEM findings
| TEM ultrastructural phenotype Total number of families (% of 134 with TEM defects defined) | Mutant known PCD gene or novel candidate | Families (n) |
| Normal TEM and inconclusive TEM analysis (no apparent defect, or few observed defects insufficient to make a diagnosis) 37 families (28%) | DNAH11* | 15 |
| HYDIN* | 6 | |
| DNAH5 | 3 | |
| CCDC103* | 2 | |
| RSPH1 | 1 | |
| OFD1 | 1 | |
| DNAI2 | 1 | |
| ZMYND10 | 1 | |
| Novel candidate gene | 4 | |
| Unsolved | 3 | |
| Outer dynein arm loss 31 families (23%) | DNAH5 | 17 |
| DNAI1 | 3 | |
| ARMC4 | 2 | |
| DNAI2 | 1 | |
| CCDC151 | 1 | |
| SPAG1 | 1 | |
| PIH1D3 | 1 | |
| Unsolved | 5 | |
| Combined inner and outer dynein arm loss 30 families (22%) | LRRC6 | 5 |
| DNAAF3 | 5 | |
| CCDC103 | 3 | |
| DNAH5 | 3 | |
| ZMYND10 | 2 | |
| DYX1C1 | 1 | |
| DNAAF1 | 1 | |
| HEATR2 | 1 | |
| DNAI1 | 1 | |
| Novel candidate gene | 4† | |
| Unsolved | 4 | |
| Microtubular disorganisation ± inner dynein arm loss 16 families (12%) | CCDC40 | 7 |
| CCDC39 | 5 | |
| CCDC65 | 1 | |
| RSPH9 | 1 | |
| RSPH1 | 1 | |
| Unsolved | 1 | |
| Central microtubular pair defect 8 families (6%) | RSPH4A | 4 |
| RSPH1 | 2 | |
| RSPH9 | 1 | |
| Unsolved | 1 | |
| Inner dynein arm loss 5 families (4%) | CCDC103 | 2 |
| CCDC164 | 1 | |
| CCDC40 | 1 | |
| Novel candidate gene | 1‡ | |
| Lack of cilia cross sections 7 families (5%) | CCNO | 2 |
| MCIDAS | 2 | |
| DYX1C1 | 1 | |
| RPGR | 1 | |
| Novel candidate gene | 1 | |
| No TEM analysis 27 families | CCDC40 | 5 |
| DNAH5 | 4 | |
| CCDC39 | 3 | |
| LRRC6 | 2 | |
| CCDC114 | 1 | |
| RSPH9 | 1 | |
| DNAH11 | 1 | |
| ZMYND10 | 1 | |
| Novel candidate gene | 2 | |
| Unsolved | 7 |
*DNAH11, HYDIN and often CCDC103 mutations are associated with normal TEM, while the other genes in this group are associated with visible TEM defects.25–27 Mutations in genes regarded during the study as candidates but since published as PCD genes were found in †2 families with CFAP300 and 1 family with DNAH9 variants, and in ‡1 family with DNAH9 variants.16 17
PCD, primary ciliary dyskinesia; TEM, transmission electron microscopy.