Table 1. Phenotypic manifestations of patients with Pearson syndrome.

Organ/tissue	Abnormality	Frequency	Reference
Central nervous system
	Epilepsy	+	[12]
	Ataxia	+	[14]
	Movement disorder (tremor)	+	[14]
	Hypotonia	++	[15]
	Failure to thrive	++	[15]
	Diffuse white matter lesions	+	[15]
	Subcortical white matte lesions	+	[9]
	Delayed motor milestones	++	[14,15]
	Attention deficit	+	[12]
	Hypomyelination (PLIC)	+	[15]
	Leigh-like features	+	[9,16]
	Hypointensities of brain stem, cerebellum, pons	+	[9,14]
	Cortical blindness	+	[12]
	Cerebral atrophy	+	[12]
	Basal ganglia calcification	+	[14]
	Lactic acidosis	+++	[15]
Peripheral nervous system
	Myopathy	+	[6]
	Ptosis	+	[13]
	Absent deep tendon reflexes	+	[15]
Eyes
	Corneal opacities	++	[8,9,17]
	Retinal compromise	+	[9]
Endocrine organs
	Diabetes	+++	[5]
	Growth retardation (short stature)	+++	[9,13,15]
	Adrenal insufficiency	++	[10,17]
	Hypoparathyroidism	+	[9]
Heart
	Complete heart block	+	[18]
	Right (left) myocardial thickening	+	[9,13,15]
	Repolarisation abnormalities	+	[9]
	QT-prolongation	+	[9]
	Bicuspid right ventricle	+	[9]
Gastrointestinal
	Exocrine pancreas insufficiency	+++	[15]
	Steatosis	+++	[16]
	Hepatomegaly	++	[15]
	Malabsorption	++	[15]
	Liver dysfunction	+++	[6,8]
	Vacuolated hepatocytes	+	[6]
	Reflux	++	[15]
	Duodenal ulcer	+	[12]
	Diarrhoea	++	[12]
Kidneys
	Renal cysts	+	[19]
	Tubulopathy	+++	[5]
	Fanconi syndrome	++	[6]
	Renal insufficiency	+	[6]
	Global sclerosis of glomerula	+	[6]
Blood
	Anemia	+++	[9,13]
	Leucopenia	+++	[9]
	Thrombocytopenia	+++	[9]
Skin
	Hyperpigmentation	+	[9]
	Café au lait spots	+	[9]
Other
	Hypospadia	+	[20]
	Cleft lip/palate	+	[20]
	Serum lactate ↑	+++	[15]
	Urine organic acids ↑	++	[15]
	3-methly-glutaconic aciduria	++	[6]
	Splenomegaly	+	[9]
	Acute myeloid leukemia	+	[9]