Demographics of study population
| Beals data4 (50 patients) | Current data (237 patients) | Total (287 patients) | |
| Gender | |||
| Male | 31 | 150 | 181 |
| Female | 19 | 87 | 106 |
| Site of involvement | |||
| Right | 16 | 60 | 76 |
| Left | 8 | 40 | 48 |
| Bilateral | 26 | 137 | 163 |
| No of affected subjects per family pedigree | |||
| 1 | 10 | 89 | 99 |
| 2 | 7 | 65 | 72 |
| 3 | 12 | 44 | 56 |
| 4 | 5 | 13 | 18 |
| >4 | 16 | 26 | 42 |