Abstract: Objective To explore the clinical and genetic characteristics of children with neuronal ceroid lipofuscinosis (NCL). Methods Clinical data of three patients diagnosed with NCL was retrospectively analyzed. Genomic DNA from peripheral blood samples from 3 families of the neuronal ceroid lipofuscinosis were extracted, and whole exome sequencing (WES) was used to identify mutations. Results The affected members of the three families presented with cognitive and motor regression, seizures of various degrees and visual impairment. Compound heterozygous mutations of c. 124 + 1 G>A inherited from her father and c. 413 C>T inherited from her mother in PPT 1 gene were found by the WES in case one. In case two, a compound heterozygous mutation of c. 181 C>T and c. 536 + 1 G>A in PPT 1 gene were found in her and her brother, in which c.181C>T mutation was inherited from her father and c. 536 + 1 G>A mutation was inherited from her mother. Compound heterozygous mutations of c. 768 G>T inherited from her father and c. 209 G>T inherited from her mother in CLN8 gene were found in patient 3 . c.768 G>T and c.209 G>T mutation were new mutation site not reported before. Conclusion Patients with PPT 1 gene mutation may present with different clinical manifestation, even if in the individual with same mutation from the same family; the findings enriched the pathogenic mutation spectrum of CLN 8.

Key words: neuronal ceroid lipofuscinosis; PPT1 gene; CLN 8 gene; clinical manifestations; genetic analysis