Table 1.

Overview of different cases with PARS2-related mutations (our case and other previously published cases).

	Our Case	Sofou et al. [10] (1st case report of PARS2 mutation)	Pronicka et al. [9]	Mizuguchi et al. [6]	Ciara et al. [8]	Yin et al. [7]	Al Balushi et al. [11]
Sex	Male	Male	Male	2 sisters	3 siblings (Two brothers and one sister)	2 sisters	Female
Family history	Eldest brother ha same phenotype.	Not mentioned	Affected siblings (no details given)	2 affected sisters, no mention of any other family member	3 affected siblings (2 brothers and 1 sister).	2 affected sisters, no mention of any other family member	Not mentioned
Longevity	Died at 21 years, brother died at 5 years	Died at the age of 16 years	Died under 2 years	Both alive at the time of report publishing(9 and 3 years of age)	Elder brother and sister died at 8.5 years; youngest brother alive at the time of report (6.5 years)	Younger one died at 4 months; older one alive at the time of report (3 years)	Alive at time of report publishing (3.3 years)
Clinical findings
Developmental delay	+	+	+	+	+	+	+
Hypotonia	+	+	+	+	+	+	Hypertonia
Microcephaly	+	+	+	+	+	+	−
Type of seizure	Infantile spasms, generalized seizure	Intractable epileptic encephalopathy	Generalized seizure	Generalized seizure	Generalized seizure	Generalized seizure	Infantile spasms
Cardiomyopathy	+	+	Not known	Not examined	+	Nil	Nil
Other organ involvements	Frequent episodes of respiratory infection, feeding difficulty	Visual impairment, feeding difficulty	Not known	Nil	Facial dysmorphism; visual impairment, hyperacusis	Feeding difficulty	Coagulation abnormalities
Diagnostic findings
MRI brain	Frontal and anterior parietal atrophy with signal changes involving caudate, lentiform nuclei, and thalami bilaterally	Supratentorial atrophy of the cerebral cortex, complete agenesis of the corpus callosum, and hypomyelination of the white matter	Done; findings not known	Diffuse hypomyelination,	Progressive volume loss of frontal lobes; widening of cortical sulci and frontal horns of lateral ventricles	Hypomyelination with cortical atrophy, decreased frontal lobe volume.	Cerebral atrophy, Bifrontal subdural hematoma.
EEG findings	High amplitude and posteriorly accentuated spike activity hypsarrhythmia	Bilateral synchronous spikes and polyspikes, mainly in posterior regions of hemispheres, with generally depressed background activity	Done; findings not known	Hypsarrhythmia	Hypsarrhythmia	Hypsarrhythmia, multifocal spikes, sharp waves with a symmetric background pattern	Not reported
Lactate levels	Normal; high only on one occasion	Elevated (serum and CSF)	Elevated (only mentioned that lactate excretion was elevated)	Elevated lactate (serum and CSF); not tested in CSF of the second sibling	CSF lactate level normal; plasma lactate level high	Elevated serum lactate levels; CSF levels were not tested	normal
Muscle/skin biopsy	Negative (skin biopsy)	Increased fiber caliber variation; no mitochondrial proliferation, and structurally abnormal mitochondria	Done; findings not known	Not done	Normal histological and histochemical picture and activities of respiratory chain complexes I–IV at the control range, except for citric synthase activity (increased at 281 nmol/min/mg)	Not done	Not done
ECHO	Initially normal. Severe degree of heart failure; EV 20%	Dilated cardiomyopathy, left ventricular hypertrophy	Done; findings not known	Not done	Dilated/hypertrophic cardiomyopathy	Normal	Normal
Genotype (ES)	Compound heterozygous variants: maternally-inherited c.283G > A (p.Val95Ile) and paternally-inherited 1091C > G (p.Pro364Arg)	Compound heterozygous variants: c.1130dupC, (p.K378 fs*1); 836C > T, (p.S279L),. located in a conserved motif of unknown function	Compound heterozygous variants: c.1091C > G (p.Pro364Arg); c.239 T > C (p.Ile80Thr)	Compound heterozygous variants in both siblings: c.283G4A (p.Val95Ile); c.607G4A (p.Glu203Lys)	Compound heterozygous variants: c.239 T > C, (p.Ile80Thr) c.1091C > G, (p.Pro364Arg)	Compound heterozygous variants c.283 G > A (p.V95I) and c.604G > C (p.R202G)	Compound heterozygous variants c.1091C > G (p.Pro364Arg) c.283G > A (p.Val95Ile)
Treatment	ACTH, and other antiepileptics; low dose aspirin, lisinopril, digoxin, carvedilol; mitochondrial “cocktail”	Antiepileptic drugs and other supportive treatment; did not receive mitochondrial “cocktail”	Antiepileptic drugs and other supportive treatment; did not receive mitochondrial “cocktail”	Antiepileptic drugs and other supportive treatment; did not receive mitochondrial “cocktail”	Antiepileptic drugs and other supportive treatment; did not receive mitochondrial “cocktail”	Antiepileptic drugs and other supportive treatment; did not receive mitochondrial “cocktail”	Not reported