Clinical and Genetic Characteristics of Mitochondrial DNA Depletion Syndrome Associated with SUCLG1 Variants in China.
This study highlights the genetic diversity and clinical variability of mitochondrial DNA depletion syndrome associated with SUCLG1 mutations in children, emphasizing the need for genetic testing for accurate diagnosis.
Where it sits
this study against the rest of the l-carnitine (levocarnitine) corpusSummary and findings
This study analyzed the genetic variants and clinical characteristics of mitochondrial DNA depletion syndrome (MDS) associated with SUCLG1 mutations in 13 children from China. Key clinical features included hypotonia, psychomotor retardation, and elevated levels of certain metabolites. All children received vitamin B complex and coenzyme Q10, with two fatalities reported.
Abstract
This study aimed to summarize the genetic variants and clinical characteristics of mitochondrial DNA depletion syndrome (MDS) associated with SUCLG1 mutations in children from China. A systematic review of cases reported in a Chinese literature database was conducted. Clinical data and genetic findings of children with MDS caused by SUCLG1 mutations were analyzed. A total of 13 cases from 9 articles were identified. The primary clinical features included hypotonia, psychomotor retardation, feeding difficulties, growth retardation, hearing impairment, and liver function impairment. Urine organic acid analysis demonstrated a mild increase in methylmalonic acid, while plasma concentrations of propionylcarnitine and/or butyrylcarnitine were elevated. Additionally, increased lactate and pyruvic acid levels were observed in both plasma and cerebrospinal fluid. Brain magnetic resonance imaging identified basal ganglion lesions and/or cerebral atrophy. A total of 14 SUCLG1 variants were identified: c.550G>A, c.751C>T, c.809A>C, c.961C>G, c.826-2A>G, c.713T>C, c.916G>T, c.619T>C, c.980dupT, c.40A>G, c.142C>T, c.601A>G, c.871G>C, and c.721_c.722delGA. Among these, the c.826-2A>G variation was the most frequently detected, present in 4 children, followed by c.550G>A. No significant correlation was found between genotype and phenotype. All 13 children were treated with vitamin B complex and coenzyme Q10. Among them, 2 died, while the remaining children exhibited clinical improvement. MDS associated with SUCLG1 mutations presents with nonspecific clinical manifestations and can affect multiple organ systems. Genetic testing is necessary for diagnosis, and no definitive treatment is currently available.
Background
Mitochondrial DNA Depletion Syndrome (MDDS) is a group of disorders characterized by a reduction in mitochondrial DNA copy number, leading to various clinical manifestations. Previous studies have identified genetic variants associated with MDDS, but the specific characteristics of these variants and their implications in different populations remain underexplored. This study aims to elucidate the clinical and genetic features of SUCLG1 variants in a Chinese cohort, which may provide insights into the syndrome's pathophysiology.
Methods
This study employs a cohort design, focusing on patients diagnosed with MDDS due to SUCLG1 variants. The sample size, specific genetic testing methods, and duration of follow-up are not detailed in the abstract. Primary outcome measures include clinical characteristics and genetic findings, while secondary outcomes are not specified.
Results
Not reported in abstract.
Interpretation
The study's findings could potentially align with existing literature on MDDS, particularly regarding the role of SUCLG1 variants. However, without specific numeric results or effect sizes reported, it is challenging to assess the clinical significance of the findings. Limitations such as the absence of detailed results and potential confounding factors in the patient population may affect the conclusions drawn from this study.
Key findings
- Not reported in abstract.
Limitations
- Not reported in abstract.