[Study of a case of Juvenile neuronal ceroid lipofuscinosis due to compound heterozygous variants of PPT1 gene].

Objective: To report and analyze a case of Juvenile neuronal ceroid lipofuscinosis (NCL) due to compound heterozygous variants of PPT1 gene.

Methods: A child who was admitted to the Department of Neurology of West China Hospital of Sichuan University in April 2021 due to "intellectual decline and behavioral abnormalities for more than 5 years and movement disorder for more than 1 year" was selected as the study subject. Clinical data of the child was collected. Trio-whole exome sequencing was carried out for the child and his parents, and clinical follow-up was conducted. This study has been approved by the Medical Ethics Committee of West China Hospital of Sichuan University (Ethic No. 2024-2286).

Results: The patient, a 13-year-old male, showed progressive mental decline, behavioral abnormalities, and movement disorders from the age of 8. Electroencephalogram showed abnormal background activities, and magnetic resonance imaging showed brain atrophy. Trio-whole exome sequencing revealed that he had harbored a paternally derived heterozygous c.272(exon3)A>C variant and a maternally derived heterozygous c.176(exon2)A>G variant of the PPT1 gene. His presentation was in keeping with previously reported juvenile NCL due to variants of the PPT1 gene.

Conclusion: The c.272(exon3)A>C and c.176(exon2)A>G compound heterozygous variants of the PPT1 gene probably underlay the Juvenile NCL in this child. Discovery of the c.176(exon2)A>G variant has expanded the mutational spectrum of this disease.