Novel mutation in PARS2 revealed highly variable phenotype of developmental and epileptic encephalopathy-75

Background and aims: Biallelic variants in mitochondrial prolyl-tRNA synthetase 2 (PARS2) are associated with developmental and epileptic encephalopathy-75 (DEE75), which is characterized by global developmental delay, seizures and brain imaging anomalies. To date, fewer than 20 patients with PARS2 mutation have been reported in previous literature, and only ten of them had detailed phenotype information.

Materials and methods: In our study, we performed whole exome sequencing for three intellectual disability patients from one family.

Results: Two novel missense PARS2 variants, c.467C>G (p. Pro156Arg) and c.1183G>C (p. Asp395His), were identified. All of our patients displayed profound intellectual disability and absent speech, while other features, including seizures, cardiomyopathy, short stature and brain MRI, varied greatly in this family. This is also the first report of ovarian dysfunction in association with PARS2 mutations.

Conclusions: We reported three patients with the longest lifespan in reported cases so far, and our results provided an opportunity to study DEE75 prognosis and symptoms in adulthood. Our results further extended the clinical and genetic spectra of PARS2 gene mutation.