Abstract: Objective To explore the clinical characteristics of infantile neuroaxonal dystrophy (INAD) and the feature of PLA2 G 6 gene mutation. Method The clinical data of an child with INAD confirmed by gene detection were retrospectively analyzed. Results The patient was a 2 year old female with an onset age of 1 year and 7 months. The clinical manifestations were psychomotor regression, hypotonia and positive pathological signs. Head MRI showed bilateral cerebellar atrophy. Electromyography and 2 h video electroencephalogram showed no abnormality. Genetic testing showed two mutations of c. 150 _ 153 del and c. 799 T>C in PLA 2 G 6 gene, which were inherited from mother and father, respectively. These were complex heterozygous variants, none of which have been detected in the normal population. The mutation of c.150 _ 153 del resulted in a change in the synthesis of amino acids starting from threonine 51 and terminating at the 30 th amino acid after the change (P.P. 51 thrfs * 30 ), which is a frameshift mutation. The mutation of c.799 T>C resulted in the change of 267 th amino acid from cysteine to arginine (p.Cys 267 Arg), which was a missense mutation. Poly-Phen 2 predicted that the mutations mentioned above could affect the protein function. Conclusion The second generation sequencing technology can accurately detect the mutation of PLA 2 G 6 gene. This study expanded the gene mutation spectrum of INAD patients in China.

Key words: infantile neuroaxonal dystrophy; clinical characteristics; PLA 2 G 6 gene