Table 2 Diagnosis and progression of symptoms

Age at diagnosis (n = 43), mean years (SD)

8.2 (4.0)

Symptomatic at diagnosis? n (%)

Yes

40 (93.0%)

No

3 (7.0%)

Initial signs/symptoms noticed by caregiver

First

(n = 40)

Second

(n = 13)

Third

(n = 5)

Fourth

(n = 2)

Decline in visual acuity

28 (70.0%)

Decline in visual acuity

6 (46.2%)

Decline in visual acuity

3 (60.0%)

Seizures

2 (100.0%)

Behavioral issues

5 (12.5%)

Behavioral issues

3 (23.1%)

Cognitive decline

1 (20.0%)

Communication issues

3 (7.5%)

Communication issues

2 (15.4%)

Gross motor delay

1 (20.0%)

Cognitive decline

1 (2.5%)

Cognitive decline

2 (15.4%)

Seizures

1 (2.5%)

Symptom prevalence and onset (years)

Symptom present?

Mean age of onset, years (SD)

 Decline in visual acuity

41 (95.3%)

5.7 (1.2)

 Insomnia

37 (86.0%)

7.4 (3.6)

 Learning difficulties

33 (76.7%)

8.3 (4.1)

 Behavioral problems

32 (74.4%)

6.3 (4.1)

 Memory loss

32 (74.4%)

9.7 (4.0)

 Anxiety

30 (69.8%)

9.7 (5.9)

 Seizures

28 (65.1%)

10.5 (3.5)

 OCD

28 (65.1%)

8.1 (3.9)

 Ataxia

24 (55.8%)

12.4 (3.6)

 Depression

17 (39.5%)

11.7 (5.7)

 Missed milestones at checkups

13 (30.2%)

3.3 (2.3)