Table 1. The mutational spectrum of probands harbouring mtDNA and OPA1 mutations.

Mutation	Below 14 years	Below 10 years	Below 6 years	7–14 years	F / S	F / M	Onset age
Total	119/304	63/201	29/94	90/210	61/243	69/235	8.7 ± 3.4
mtDNA	89/304	38/201	6/94	83/210	30/59	10/79	10.6 ± 2.8
OPA1	26/304	24/201	21/94	5/210	8/18	4/22	5.8 ± 3.4
OPA3	4/304	1/201	2/94	2/210	2/2	0/4	6 ± 3.16

F / S: Familial / Sporadic; F / M: Female / Male