| Present study | Previous study—19972 | |
| Number of cases | 267 | 1176 |
| Detection rate (per 100 000) | 0.94 | 0.35 |
| Prevalence (per 100 000) | 10.5 | 3.16 |
| Sex ratio (male:female) | 1:2.2 | 1:1.8 |
| Patients younger than 10 years old at onset (%) | 15.1% | 47.8% |
| Pattern of age distribution | 2 peaks | 2 peaks |
| Highest peak in age distribution (in years) | 45–49 | 10–14 |
| Second peak in age distribution (in years) | 5–9 | 40–49 |
| Patients with family history | 15.4% | 10.0% |