Table 1. Number of patients (%) by sex, age at the initial visit, and age of onset.

	Number of patients (%)
Gender
Male	2,590 (51.8)
Female	2,410 (48.2)
Age (at initial visit)
0–2 yr	205 (4.1)
3–10 yr	1,040 (20.8)
11–18 yr	1,200 (24.0)
19–30 yr	1,885 (37.7)
31–40 yr	540 (10.8)
41–50 yr	85 (1.7)
> 50 yr	45 (0.9)
Age of onset
<1 yr	749 (15.0)
1–2 yr	652 (13.0)
3–6 yr	955 (19.1)
7–18 yr	1,498 (30.0)
>18 yr	1,146 (22.9)