[Analysis of mitochondrial gene mutations in a child with Leigh syndrome].

OBJECTIVE

To explore the genetic basis for a child with Leigh syndrome.

METHODS

Clinical features and laboratory test of the patient were analyzed. Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) of the mitochondrial genome were carried out. Next generation sequencing (NGS) was used to capture and sequence nuclear genes related to mitochondrial structure and function.

RESULTS

The child presented with developmental delay, unsteady gait, falling episodes, bilateral upper extremity tremor, muscle hypertonia, convulsions, and mouth angle asymmetry. Serum lactic acid was significantly increased. Cranial MRI showed abnormal signal in bilateral cerebellar hemispheres, bilateral basal ganglia, left thalamus, and corona radiata. Her mother and brother did not show any anomalies. Sanger sequencing revealed the child, her mother and brother all carried the MT-ND3 m.10191 T>C mutation, with heterogeneous rates respectively being 74.34%, 9.73%, and 6.28%. MLPA revealed heterogeneity of (MT-ND6, MTCYB-390nt)] deletion in all three individuals. No significant mutation was found by NGS sequencing of the children, their parents and brother.

CONCLUSION

Leigh syndrome can be caused by the simultaneous existence of multiple mitochondrial genes, and multiple mutations may play a synergic role in the occurrence of the disease.