Table 1.

Demographics and Characteristics of Our Cohort

	Frequency (n = 404)	Percentage (95% CI)
Age at mitochondrial disease diagnosis
<18 y	243	60.1
18–44 y	95	23.5
45–64 y	27	6.7
≥65 y	2	0.5
Unknown	37	9.2
Age at enrollment in the NAMDC Patient Registry
<18 y	187	46.3
18–44 y	128	31.7
45–64 y	72	17.8
≥65 y	17	4.2
Sex
Female	230	56.9
Male	174	43.1
Race/Ethnicity
White	347	85.9
Asian	16	4
Hispanic or Latino	16	4
Black/African American	8	2
Multiracial	7	1.7
American Indian/Alaska Native	3	0.7
Native Hawaiian/Pacific Islander	1	0.2
Other/Unknown	6	1.5
Type of associated pathogenic molecular genetic mutation
Mutation of nuclear DNA	158	39.1 (34.3–44.1)
Mitochondrial DNA defects	228	0.4 (51.4–61.3)
Mutation(s) in both	18	4.5(2.7–7)
Presence of a clinical mitochondrial syndrome diagnosis
Diagnosis identified	389	96.3
Undetermined/unknown	15	3.7