Variants in the SARS2 gene cause HUPRA syndrome with atypical features: two case reports and review of the literature

Abstract Hyperuricemia, pulmonary hypertension, renal failure in infancy, and alkalosis (HUPRA syndrome) is a rare autosomal recessive mitochondrial disease with a prevalence of <1:1 000 000, due to variations in the seryl-tRNA synthetase (SARS2) gene encoding SARS on chromosome 19 (19q13.2). This study investigated two Palestinian girls from the same village who presented with progressive renal failure during infancy, with atypical clinical manifestations of HUPRA syndrome including leukopenia, anemia, salt wasting, renal failure, marked hyperuricemia, hypercholesterolemia, hyperlactatemia, and hypertriglyceridemia but without pulmonary hypertension or alkalosis. Instead, they showed acidosis on routine follow-up, distinguishing them from previous cases. Using single whole exome sequencing, we identified two homozygous pathogenic variants in the SARS2 gene (c.1175A>G (p.D392G)) and (c.1169A>G (p.D390G)). These cases with their unique phenotypes, expand the SARS2 pathogenic variant spectrum and describe clinical differences between homozygous and compound heterozygous variants.