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Table 2 Clinical features, muscular biopsy, molecular diagnosis and outcome in enrolled patients

From: Impact of cardiovascular involvement on the clinical course of paediatric mitochondrial disorders

 

Overall

Patients without CVI

Patients with CVI

p-value

Number of patients (%)

86

55 (64%)

31 (36%)

 

Males/Females

0.5

0.15

1.8

< 0.01

Mean age at diagnosis (years; ±SDS)

6.4 (±8.58)

7.8 (±10.08)

5.75 (±7.67)

0.3

Mean age at LFUP (years; ±SDS)

11.4 (±10.1)

11.8 (±9.17)

10.98 (±11.5)

0.7

Muscular biopsy (n° patients; %)

55 (63.9%)

37 (67.2%)

18 (58%)

0.4

Respiratory chain enzyme deficiency (n°;%)

49 (57%)

35 (63.6%)

14 (45%)

 

- Complex I

12 (14%)

9 (16.3%)

3 (9.7%)

0.7

- Complex II

1 (1.2%)

1 (1.8%)

–

0.5

- Complex III

2 (2.3%)

2 (3.6%)

–

0.4

- Complex IV

3 (3.5%)

2 (3.6%)

1 (3.2%)

0.8

- Complex V

4 (4.6%)

2 (3.6%)

2 (6.4%)

0.3

- Combined deficiencies

27 (31.4%)

19 (34.5%)

8 (25.8%)

0.8

Molecular analysis (n°;%)

57 (66.3%)

31 (56.3%)

26 (83.8%)

 

- MTTL1 (A3243G)

8 (9.3%)

3 (5.4%)

5 (16.1%)

0.4

- TMEM70

5 (5.8%)

–

5 (16.1%)

< 0.01

- NARP

4 (4.6%)

3 (5.4%)

1 (3.2%)

0.4

- Barth syndrome

4 (4.6%)

–

4 (12.9%)

0.02

- POLG

2 (2.3%)

2 (3.6%)

–

0.4

- ACAD9

2 (2.3%)

1 (1.8%)

1 (3.2%)

0.4

- SURF1

1 (1.2%)

1 (1.8%)

–

0.4

- NDFUS1

1 (1.2%)

–

1 (3.2%)

0.8

- SDHB

1 (1.2%)

1 (1.8%)

–

0.4

- ELAC2

1 (1.2%)

–

1 (3.2%)

0.4

- DGUOK

1 (1.2%)

1 (1.8%)

–

0.4

- TK2

1 (1.2%)

1 (1.8%)

–

0.4

- tRNA (Glu)

1 (1.2%)

–

1 (1.2%)

0.4

- NAHD dehydrogenase (complex I) subunits:

7 (8.1%)

5 (9%)

2 (6.5%)

0.07

o MTND1

2 (2.3%)

1 (1.8%)

1 (3.2%)

 

o MTND2

1 (1.2%)

1 (1.8%)

–

 

o MTND3

1 (1.2%)

–

1 (3.2%)

 

o MTND5

1 (1.2%)

1 (1.8%)

–

 

o MTND6

2 (2.3%)

2 (3.6%)

–

 

- MTCYB1

1 (1.2%)

1 (1.8%)

–

0.4

- MT-CO1

1 (1.2%)

1 (1.8%)

–

0.4

- MT-TC

1 (1.2%)

1 (1.8%)

–

0.4

- Leber’s hereditary optic neuropathy

1 (1.2%)

1 (1.8%)

–

0.4

- Kearns-Sayre disease

2 (2.3%)

1 (1.8%)

1 (3.2%)

0.8

- Sengers disease

1 (1.2%)

–

1 (3.2%)

0.2

- Large mt-DNA depletion

2 (2.3%)

1 (1.8%)

1 (3.2%)

0.8

- TIMMDC1

1 (1.2%)

1 (1.8%)

–

0.4

- NUBPL

1 (1.2%)

1 (1.8%)

–

0.4

- SFXN4

1 (1.2%)

1 (1.8%)

–

0.4

- ATAD3A

1 (1.2%)

–

1 (3.2%)

0.2

- DARS2

1 (1.2%)

1 (1.8%)

–

0.4

- SLC19A3

1 (1.2%)

–

1 (3.2%)

0.2

Extra-cardiac manifestations (n°; %)

- Failure to thrive

28 (32.5%)

12 (21.8%)

16 (51%)

0.1

- Neurologic

52 (60.4%)

33 (60%)

19 (52.7%)

0.9

o neurodevelopmental delay

36 (42%)

21 (38%)

15 (48%)

–

o epilepsy

28 (32.5%)

14 (25.5%)

4 (13%)

–

o hypo- or hypertonia

17 (19.7%)

7 (12.7%)

10 (32%)

–

o recurrent headache/cerebral stroke

6 (7%)

3 (5.5%)

3 (9.7%)

-

-

- Ocular

16 (18.6%)

6 (11%)

10 (32%)

0.1

- Hearing loss

8 (9.3%)

2 (3.6%)

6 (19.3%)

0.3

- Diabetes

5 (5.8%)

1 (1.8%)

4 (13%)

0.1

- Renal failure

6 (7%)

1 (1.8%)

−5 (16%)

0.04

Cardiac involvement

31 (36%)

–

31 (100%)

n.a.

Clinical presentation

- Asymptomatic

  

18 (58%)

 

- Cardiac murmur

  

5 (16%)

 

- Heart failure

  

6 (19.3%)

 

- Prenatal suspicion

  

2 (6.4%)

 

- Systemic hypertension

  

3 (9.7%)

 

Baseline electrocardiographic anomalies (n°;%)

  

23 (74.1%)

n.a.

- Atrial enlargement

  

3 (9.6%)

 

- LV hypertrophy/volume overload

  

14 (45%)

 

- Right bundle branch block

  

7 (22.5%)

 

- Ventricular pre-excitation

  

2 (6.4%)

 

- Increased QTc interval

  

1 (1.8%)

 

- Premature atrial complexes

  

1 (1.8%)

 

Baseline echocardiographic findings (n°;%)

- HCM

  

13 (42%)

 

- HCM/NC

  

4 (13%)

 

- DCM

  

8 (25.8%)

 

- PAH

  

4 (13%)

 

Major cardiac events (n°; %)

  

6 (19%)

 

- Hospitalization due to HF

  

2 (6.4%)

 

- Decease due to HF

  

2 (6.4%)

 

- Resuscitated cardiac arrest

  

1 (1.8%)

 

- PM implantation (high-grade AV block)

  

1 (2.8%)

 

- Sudden cardiac death

  

1 (1.8%)

n.a.

Mortality

26 (30.2%)

12 (21.8%)

14 (45.1%)

< 0.01

- Cardiac cause

  

3 (9.6%)

 

- Respiratory infection

  

2 (6.4%)

 

- Metabolic crisis

  

2 (6.4%)

 

- Stroke

  

1 (1.8%)

 

- Not assessed

  

6 (19%)

 
  1. Abbreviations: CVI cardiovascular involvement; LFUP last follow-up; LV left ventricle; HCM hypertrophic cardiomyopathy; NC non-compaction; DCM dilative cardiomyopathy; PAH pulmonary hypertension; HF heart failure; PM pace-maker; AV atrioventricular