[P1-156] Analysis of Clinical Features and Genetic Characteristics of Encephalomyopathic Mitochondrial DNA Depletion Syndrome in 5 Cases
[Objective] To analyze the clinical and genetic characteristics of mitochondrial DNA depletion syndrome caused by succinyl-CoA ligase deficiency.
[Method] The clinical features and genetic characteristics of 5 cases with mitochondrial DNA depletion syndrome in Beijing Children 's Hospital from November, 2013 to May, 2016 were analyzed.
[Results] The ratio of male to female was 4: 1 and the age of onset was 5 months after birth. All of the patients showed hearing loss, developmental delay, feeding difficulties and growth retardation. Brain MRI showed symmetric basal ganglia abnormal signals with or without atrophy, with brain atrophy-like changes, or only showed brain atrophy-like changes. Urine organic acid analysis prompted a slightly higher level of methylmalonic acid (normal 2.67-30.7 times). 1 case had SUCLA2 c.534 + 1G> A homozygous mutation and 4 cases had SUCLG1 gene defects, with a total of seven mutations (c.826-2A> G, c.550G> A, c.916G> T, c.619T> C, c.980dupT, c.961C> G, c.713T> C), in which four were missense mutations, the other three were shear, frameshift and nonsense mutation respectively. Except c.961C> G, the other six mutations were novel mutations.
[Conclusions] Mitochondrial DNA depletion syndrome caused by defects of succinyl-CoA ligase (SUCL) is characterized by relatively specific clinical features and biological markers, and SUCLA2 and SUCLG1 gene testing are helpful in the early diagnosis.
[Method] The clinical features and genetic characteristics of 5 cases with mitochondrial DNA depletion syndrome in Beijing Children 's Hospital from November, 2013 to May, 2016 were analyzed.
[Results] The ratio of male to female was 4: 1 and the age of onset was 5 months after birth. All of the patients showed hearing loss, developmental delay, feeding difficulties and growth retardation. Brain MRI showed symmetric basal ganglia abnormal signals with or without atrophy, with brain atrophy-like changes, or only showed brain atrophy-like changes. Urine organic acid analysis prompted a slightly higher level of methylmalonic acid (normal 2.67-30.7 times). 1 case had SUCLA2 c.534 + 1G> A homozygous mutation and 4 cases had SUCLG1 gene defects, with a total of seven mutations (c.826-2A> G, c.550G> A, c.916G> T, c.619T> C, c.980dupT, c.961C> G, c.713T> C), in which four were missense mutations, the other three were shear, frameshift and nonsense mutation respectively. Except c.961C> G, the other six mutations were novel mutations.
[Conclusions] Mitochondrial DNA depletion syndrome caused by defects of succinyl-CoA ligase (SUCL) is characterized by relatively specific clinical features and biological markers, and SUCLA2 and SUCLG1 gene testing are helpful in the early diagnosis.