Table 3 Laboratory and magnetic resonance imaging (MRI) findings in SURF1 deficiency

Blood

Metabolic acidosis

21/33

64

Elevated lactate

31/38

81

Cerebrospinal fluid

Elevated lactate

30/30

100

Muscle

Reduced/absent COX histochemistry

23/33

70

Type I fibre predominance

8/33

24

Elevated muscle lipid content

16/33

48

Reduced muscle COX activity

25/26

96

Fibroblast

Reduced fibroblast COX activity

25/25

100

Nerve conduction studies

Peripheral neuropathy

13/16

81

MRI lesions

Midbrain

12/33

36

Pons

10/33

30

Medulla

15/33

45

Putamen

16/33

48

Globus pallidus

14/33

42

Caudate nucleus

12/33

36

Subthalamic nucleus

4/33

12

Periaqueductal grey matter

4/33

12

Olivary nuclei

3/33

9

Red nuclei

2/33

6

Cerebellar white/grey matter

6/33

18

Cerebellar atrophy

3/33

9

Dentate nucleus

13/33

39

Cerebellar peduncles

8/33

24

Leukoencephalopathy

2/33

6