PARS2 was previously implicated in a mitochondrial phenotype featuring neurodegeneration and liver involvement (Alpers syndrome) based on compound heterozygous pathogenic variants.22–24 Interestingly, in one family we show that homozygosity for a variant in PARS2 (NM_152268.3:c.283G>A:p.[Val95Ile]), previously reported only in trans with another allele, fully segregated with global developmental delay, epilepsy, and brain atrophy but without lactic acidosis or renal or liver involvement (Fig. 2). Here, PARS2 is linked to Global developmental delay.