Table 2 Cognitive functioning and mental health (n = 33)

Average or above IQ (IQ ≥ 80; n = 13)

1

mDNA 3243 A > G

M

10

S

121³

129

105

65

8

5

7

9

10

62

57

70

59

77,17

2

mDNA 3243 A > G

M

16

R

121⁵

113

125

97

3

mitochondrial deletion, 9101_14603del

F

16

R

123³*

8

6

2

7

9

71

80

89

68

61,96

4

mDNA 3242 A > G

F

9

R

120³*

5

mitochondrial deletion, 8470_13446del

M

13

R

120³*

7

5

7

8

12

46

50

57

50

70,65

6

mitochondrial deletion, 8649_16084del

M

11

R

118⁴

130

108

100

11

14

57

50

58

64

7

mDNA 3243 A > G

M

15

R

116³*

7

7

10

8

12

63

57

85

53

50

8

NDUFS7, c.364G > A, (p.Val122Met), homozygous

F

5

R

110²*

8

10

9

mDNA 04,300 A > G

M

5

R

92²

87

100

94

6

7

70

64

70

57

10

mDNA 8993T > G

M

7

R

87²

110

85

55

2

6

8

11

mDNA 3243A > G

M

13

R

84⁴

78

92

83

11

2

51

54

53

53

65,22

12

FXN homozygous expansion repeats

M

11

R

84³*

11

11

11

8

10

42

50

50

50

64,13

13

mDNA 4404T > C

F

10

R

84³*

39,13

Borderline IQ (IQ = 70–79; n = 8)

14

mDNA 3243 A > G

M

11

R

78³

88

72

67

9

8

5

11

11

60

57

58

61

15^†

mDNA 3243 A > G

M

12

S

78³

86

73

67

9

5

TD

8

9

55

54

57

53

16

mDNA 7507 A > G

M

7

S

78³*

TD

TD

TD

6

11

73

57

66

66

43,48

17^†

SURF1, c.312_321delinsAT, (p.Leu105*), homozygous

F

2

-

-6

77¹

18^†

RRM2B, 1045 G > A, (pAla349Thr), homozygous

F

1

-

-3

72¹

19

NDUFS1, c.683T > C, (p.Val228Ala), 737 + 3 A > G (spl?)

F

15

S

71³

73

75

83

8

2

6

6

9

80

82

78

83

27,17

20

mDNA 3243 A > G

F

16

R

70³*

10

11

10

11

10

69

59

60

63

45,65

21

mDNA 09185T > C

M

8

R

70³

76

68

75

3

1

2

5

8

41

50

50

51

58,7

Clinically low IQ (IQ < 70; n = 12)

22

mDNA 3243 A > G

F

12

S

62³

79

55

67

4

2

1

6

7

58

55

51

70

23

mDNA 3243 A > G

M

16

S

58³

63

58

55

1

5

24

FBXL4 c.1641_1642del (p.Cys547*), c.1252G > C (p.Ala418Pro)

F

7

S

55⁶

62

52

52

77

25

SDHA c.1535G > A (p.Arg512Gln), c.1753C > T (p.Arg585Trp)

M

4

S

 < 55²

 < 55

55

69

56

76

77

26

SDHA, c.64-2A > G, splicing defect homozygous

M

11

S

50⁶

43

50

56

70

27

RARS2, c.442A > G (p.Thr148Ala), c.1519G > A (p.Glu507Lys)

M

17

S

46³

 < 55

 < 55

 < 55

1

5

59

57

78

64

28

RARS2, c.442A > G (p.Thr148Ala), c.1519G > A (p.Glu507Lys)

F

12

S

46³*

1

1

4

5

56

50

57

68

29

OPA1, c.1156_1157del (pLeu386Glufs*2)

F

3

-

-18

46

50

56

62

30

FBXL4, c.1361A > C (p.Gln454Pro), homozygous

M

6

S

-33

31

SUCLA2 1271delG9p (pGly424Aspfs*18), homozygous

M

4

S

NA^

32

ACO2 2012G > A (pArg671Gln), 2050C > T(pArg684Trp)

F

8

S

NA^

51

50

52

52

63,04

33^†

NDUFS7 c.364G > A(pVal122Met) homozygous

M

14

S

NA^