Table 1.

Comparison of neurological manifestations in the current study (n = 5).

	Case 1	Case 2	Case 3	Case 4	Case 5
Age of onset	6 months	4 months	5 months	6 months	6 months
Gender	Girl	Boy	Boy	Boy	Boy
Clinical features	Language delay, followed by developmental regression, dyskinetic movement disorder, and sensorineural hearing loss	Global developmental delay, central hypotonia, choreoathetoid movements, and ophthalmoplegia	Global developmental delay and generalized dystonia	Developmental delay followed by regression, central hypotonia, optic atrophy, and hearing loss	Normal development followed by developmental arrest and generalized dystonia
Episodic encephalopathy	None	None	None	None	None
Seizures	None	None	None	None	None
Hydrocephalus	None	None	None	Present	Present
Consanguinity	None	None	None	None	None
Lactic acidosis	Present	Present	Present	Present	Present
Acylcarnitine profile	Elevated C3 and C4DC-Acylcarnitine	Elevated C3 and C4DC-Acylcarnitine	Elevated C3, C5-OH, and C4DC-Acylcarnitine	Elevated levels of methyl malonyl carnitine and hydroxy isovaleryl carnitine	Elevated C5OH and C4DC-Acylcarnitine
Urine MMA	Present	Present	Present	Present	Present
Age at MRI	9 years	14 months	1 year	1 year	2 years
Brain MRI	Unremarkable	Bilateral caudate, putamen, and globi pallidi hyperintensity	Bilateral caudate and lentiform nuclei hyperintensity Periventricular white matter hyperintensity	Bilateral caudate, lentiform nuclei hyperintensity, and atrophy Hydrocephalus	Bilateral globus pallidi, caudate and putamen hyperintensity, and atrophy Hydrocephalus Diffuse cerebral atrophy Periventricular and subcortical white matter hyperintensity
Genetic mutation	Homozygous missense mutation in SUCLA2 gene. c.985A > G, p.(Met329Val)	Compound heterozygous mutation in SUCLG1 gene. (i) c.201G > A, p. (Gln67), (ii) c.825 + 4A > T	Homozygous missense mutation in SUCLG1 gene c.358G > C (p.Val120Leu)	Homozygous missense mutation in SUCLG1 gene c.358G > C (p.Val120Leu)	Homozygous missense mutation in SUCLG1 c.358G > C (p.Val120Leu)
Therapeutic interventions	Mitochondrial cocktail	Supportive symptomatic management	Oral and injectable B12, carnitine, clonazepam, and trihexyphenidyl	Mitochondrial cocktail, B12 injections, trihexyphenidyl, baclofen, and bilateral pallidotomy	Trihexyphenidyl, baclofen, carnitine, coenzyme Q, and oral B12
Follow-up duration	14 years	4 years	2 years	2 years	3 years
Outcome	Slow steady gain of milestones, intermittent dyskinesia, no regression, and ambulatory	Global developmental delay with speech regression after 1 year of age but steady gains in other domains, recurrent vomiting	Severe generalized dystonia, spastic quadriparesis, severe developmental delay, and non-ambulatory	Severe generalized dystonia, severe developmental delay, and non-ambulatory	Intermittent dystonia, lower limb spasticity, slow gain of milestones, non-ambulatory, and difficulty sleeping