Table 1 Baseline and follow-up assessment of patients diagnosed with Primary Mitochondrial Disorders

Family history

• Pattern of transmission (autosomal, X-linked, matrilineal)

• Recurrence of distinctive features:

- Myopathy

- Mental retardation/epilepsy

- Precocious death/stillbirth

- Diabetes

- Hearing loss

- Cardiovascular diseases

- Short stature

- Ocular involvement.

Clinical examination

• Auxological parameters (weight, length/stature, cranial circumference)

• Vital parameters (blood pressure, heart rate, respiratory rate, oxygen saturation)

• Assessment of neurological status and cognitive development

Specialist evaluations

• Audiological screening

• Ophthalmologic screening in order to exclude:

- retinitis

- cataract

- optic nerve atrophy

- progressive loss of vision

Cardiologic evaluation

• Clinical examination

• 12-lead ECG and transthoracic echocardiograph

Brain Magnetic Resonance

• Common findings:

- Leigh syndrome

- Focal hypodense lesions

- Cortical and cerebellar atrophy

- White matter hyperintensity

- Basal ganglia involvement

- Agenesis/hypoplasia of the corpus callosum

Brain MR spectroscopy

Abnormal accumulation of lactate in the parenchyma and cerebrospinal fluid

Laboratory investigation

• Complete blood count

• Liver and renal functional tests

• Blood fasting glucose

• Blood gas analysis

• Plasma lactate levels

• Creatine phosphokinase (CPK)

• Plasma amino acids

• Urine amino and organic acids

• Redox status

• Acylcarnitine profiles