AUTHOR=Miao Sui-Bing , Guo Hui , Kong De-Xian , Zhao Yuan-Yuan , Pan Shu-Hong , Jiang Yan , Gao Xing , Wu Xiao-Hua TITLE=Case report: Analysis of novel compound heterozygous TPP1 variants in a Chinese patient with neuronal ceroid lipofuscinosis type 2 JOURNAL=Frontiers in Genetics VOLUME=13 YEAR=2022 URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2022.937485 DOI=10.3389/fgene.2022.937485 ISSN=1664-8021 ABSTRACT=

Neuronal ceroid lipofuscinosis type 2 (CLN2) is an autosomal recessive neurodegenerative disease caused by variants in the TPP1 gene that lead to the deficiency of the lysosomal enzyme tripeptidyl peptidase I (TPP1) activity. Herein, we report a rare case of CLN2 caused by two novel variants of TPP1. The patient presented with seizures at onset, followed by progressive cognitive impairment, motor decline, and vision loss. Novel compound heterozygous variants, c.544_545del and c.230-3C>G, in TPP1 were identified by whole-exome sequencing. The variant assessment showed that the c.544_545del is a frameshift variant mediating mRNA decay and that c.230-3C>G is a splice variant generating aberrantly spliced TPP1 mRNA, as confirmed by a Splicing Reporter Minigene assay. In conclusion, clinical history, variant assessment, and molecular analyses demonstrate that the novel compound heterozygous variants are responsible for CLN2 disease in this patient. This study expands the mutation spectrum of TPP1.